With prices of rice and other cereals soaring and granaries emptying, it might take a second green revolution to avert widespread famine.

China is the largest producer and consumer of rice in the world and a pioneer in applying hybrid rice technology. Although hybrid rice has contributed greatly to Chinese agriculture in the past decades, its potential to improve grain quality further is being questioned. However, to meet the challenges posed by severe crop damage by pests and diseases, the extensive use of pesticides and chemical fertilizers, and a shortage of water and energy, more elite rice cultivars are needed. In recent years, China has seen continued improvements in rice genetics, powered by functional genomics as a way forward to safeguard its rice production. Here, we briefly review the current status of rice breeding in China through strategies integrating hybrid rice technology, molecular marker-assisted breeding, functional genomics and genetically modified rice.

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小麦杂种优势利用途径与研究进展张爱民黄铁城（中国农业大学北京100094）国内目前主要是通过常规的品种间杂交选育小麦优良品种。近些年来，由于我国常规小麦育种工作处于爬坡阶段，育成的新品种没有取得重大突破。而利用杂种第一代优势则是各类作物育种共同的发展...

小麦杂种优势利用途径与研究进展张爱民黄铁城（中国农业大学北京100094）国内目前主要是通过常规的品种间杂交选育小麦优良品种。近些年来，由于我国常规小麦育种工作处于爬坡阶段，育成的新品种没有取得重大突破。而利用杂种第一代优势则是各类作物育种共同的发展...

Global food security demands the development and delivery of new technologies to increase and secure cereal production on finite arable land without increasing water and fertilizer use. There are several options for boosting wheat yields, but most offer only small yield increases. Wheat is an inbred plant, and hybrids hold the potential to deliver a major lift in yield and will open a wide range of new breeding opportunities. A series of technological advances are needed as a base for hybrid wheat programmes. These start with major changes in floral development and architecture to separate the sexes and force outcrossing. Male sterility provides the best method to block self-fertilization, and modifying the flower structure will enhance pollen access. The recent explosion in genomic resources and technologies provides new opportunities to overcome these limitations. This review outlines the problems with existing hybrid wheat breeding systems and explores molecular-based technologies that could improve the hybrid production system to reduce hybrid seed production costs, a prerequisite for a commercial hybrid wheat system.

Summary The transition from vegetative to reproductive phase, flowering per se , floral organ development, panicle structure and morphology, meiosis, pollination and fertilization, cytoplasmic male sterility (CMS) and fertility restoration, and grain development are the main reproductive traits. Unlocking their genetic insights will enable plant breeders to manipulate these traits in cereal germplasm enhancement. Multiple genes or quantitative trait loci (QTLs) affecting flowering (phase transition, photoperiod and vernalization, flowering per se ), panicle morphology and grain development have been cloned, and gene expression research has provided new information about the nature of complex genetic networks involved in the expression of these traits. Molecular biology is also facilitating the identification of diverse CMS sources in hybrid breeding. Few Rf (fertility restorer) genes have been cloned in maize, rice and sorghum. DNA markers are now used to assess the genetic purity of hybrids and their parental lines, and to pyramid Rf or tms (thermosensitive male sterility) genes in rice. Transgene(s) can be used to create de novo CMS trait in cereals. The understanding of reproductive biology facilitated by functional genomics will allow a better manipulation of genes by crop breeders and their potential use across species through genetic transformation.

Cytoplasmic control of susceptibility in maize to yellow leaf blight caused by Phyllostica zeae has been hypothesized in light of: (i) increased susceptibility to the disease of all inbreds with cytoplasm of the Texas male-sterile type, in contrast to the resistance of their normal counterparts; and (ii) uniformity in susceptibility of plants within the population of any inbred line with the Texas male-sterility type cytoplasm. Susceptibility largely governed by a cytoplasmic factor(s) conferring malesterility would insure uniform susceptibility to yellow leaf blight of maize hybrids, even though many inbred lines with a high degree of resistance are available.

以10套同核异质(N、C、Rb、ES)品系及Cms-C胞质背景的３个杂交种(F1)为试材．对田间观测的4个病理指标的鉴定和分析结果表明：(1)除乳熟期病情指数外，其余３个病理指标的结果显示出C小种对C群CI亚群雄性不育胞质具有专化性侵染的特点．但在不同病理指标、不同核型之间所表观的专化性程度却有较大差别；CⅡ、C Ⅲ亚群胞质无专化侵染现象．(2) C小种的致病力小于Ｔ小种．

以10套同核异质(N、C、Rb、ES)品系及Cms-C胞质背景的３个杂交种(F1)为试材．对田间观测的4个病理指标的鉴定和分析结果表明：(1)除乳熟期病情指数外，其余３个病理指标的结果显示出C小种对C群CI亚群雄性不育胞质具有专化性侵染的特点．但在不同病理指标、不同核型之间所表观的专化性程度却有较大差别；CⅡ、C Ⅲ亚群胞质无专化侵染现象．(2) C小种的致病力小于Ｔ小种．

Recently two new kinds of rice genetic tools viz., photoperiod sensitive genic male sterile (PGMS) lines and thermo-sensitive genic male sterile (TGMS) lines have been successfully developed in China. Their male sterility is mainly controlled by a pair of recessive nuclear genes, and has no relation to cytoplasm. Exploitation of these MSlines to develop hybrid rice has the following advantages over the classical three-line or CMS system:1. B line is not needed. Under longer daylength the PGMS lines or under higher temperature the TGMS lines show complete pollen sterility, thus they can be used for hybrid seed production in these conditions. Under shorter daylenghth or temperate conditions they show almost normal fertility, thus can multiply themselves.2. The choice of parents in developing heteroic hybrids is greatly broadened.Studies showed that over 97.6% varities tested (within subspecies) can restore such MS lines. In addition, PGMS and TGMS genescan be easily transferred to any rice cultivar.3. There is no negative effects caused by sterile cytoplasm and the unitary cytoplasm situation will be avoided.Several better inter-varietal hybrid combinations produced by two-line,system were under regional trial and farmer's field trail in 1989.The results were promising, some of them outyielded the best existing hybrids by about 5%. It is estimated that the planting area of two-line system hybrid rice will be extended more than 17,000 ha in 1990.The development of inter-subspecies especially indica/japonica hybrids with very high yield potential through two-line system is still under way.The major problems presented in such F_1 hybrids, namely semi-sterility, too tall plant height and long growth duration, have been overcome. But the plumpness of many fertilized grains is not good in most combinations. Now, efforts are focused on solving this problem.

A breeding program was initiated at the International Rice Research Institute (IRRI) in 1990 to develop thermosensitive genic male sterile (TGMS) rice lines for developing two-line rice hybrids for the tropics. The TGMS trait was transferred from a temperate japonica TGMS mutant, Norin PL 12, to indica and tropical japonica rice varieties using the pedigree selection procedure. Six new TGMS rice lines adapted to tropical conditions were developed which showed complete pollen and spikelet sterility when maximum temperature was higher than 30 ° C 1–2 week after panicle initiation. However, up to 85.5% spikelet fertility was observed when these lines were exposed to 26–29 ° C during the critical stage. Using two of these TGMS lines, some heterotic rice hybrids showing 1–1.6 t/ha higher grain yield than the inbred check varieties were identified in unreplicated observational yield trial conducted at IRRI. Two of the six two-line hybrids yielded significantly higher than the check variety in a replicated preliminary yield trial.

Apparent Amylose Content (AAC), regulated by the Waxy gene, represents the key determinant of rice cooking properties. In occidental countries high AAC rice represents the most requested market class but the availability of molecular markers allowing specific selection of high AAC varieties is limited. In this study, the effectiveness of available molecular markers in predicting AAC was evaluated in a collection of 127 rice accessions (125 japonica ssp. and 2 indica ssp.) characterized by AAC values from glutinous to 26%. The analyses highlighted the presence of several different allelic patterns identifiable by a few molecular markers, and two of them, i.e., the SNPs at intron1 and exon 6, were able to explain a maximum of 79.5% of AAC variation. However, the available molecular markers haplotypes did not provide tools for predicting accessions with AAC higher than 24.5%. To identify additional polymorphisms, the re-sequencing of the Waxy gene and 1kbp of the putative upstream regulatory region was performed in 21 genotypes representing all the AAC classes identified. Several previously un-characterized SNPs were identified and four of them were used to develop dCAPS markers. The addition of the SNPs newly identified slightly increased the AAC explained variation and allowed the identification of a haplotype almost unequivocally associated to AAC higher than 24.5%. Haplotypes at the waxy locus were also associated to grain length and length/width (L/W) ratio. In particular, the SNP at the first intron, which identifies the Wxa and Wxb alleles, was associated with differences in the width of the grain, the L/W ratio and the length of the kernel, most likely as a result of human selection.

【Objective】The objective of this study is to identify and reveal the transition of the male sterile gene(s) in photoperiod- and temperature-sensitive genic male sterile(P/TGMS) lines utilized in the two-line hybrid rice system in China.【Method】A total of 90 environment-conditioned genic male sterile(EGMS) lines including descendents of Nonken 58 S,Annong S-1 and Zhu 1S,were used in the present study.Genomic DNAs were extracted from rice leaves by modified CTAB.One functional CAPS marker based on the C to G mutation in the long non-coding RNA(lnc R) gene was designed for PGMS genotyping; Namely,a pair of primers NK-F(5′-ATCCCACAAATCCTTTAGCA-3′) and NK-R(5′-CCGTTATAGATAGACCCGAGA-3′) were used to amplify segments harboring the mutation site,followed by digestion overnight at 37℃ with restriction endonuclease Rsa I and separation on 1% agarose gel electrophoresis.Homozygous PGMS allele(lnc Rm)(329 bp) can be readily distinguished from homozygous wild type(lnc Rwt)(414 bp) and heterozygous type(lnc Rm/lnc Rwt)(414 and 329 bp) based on the sizes of digestion products.For TGMS genotyping,functional d CAPS markers were deployed with the following steps: Two pairs of primers RNZ1F(5′-ACCGCGCCGCCACCGGGTCGGCCGGAG-3′)/RNZR(5′-TGAAGAGGAACTCCTGCGAGACGG-3 ′),RNZ2F(5′-ACCGC GCCGCCACCGGGTCGGCCCAAG-3′)/RNZR were used to amplify segments harboring the mutation site(SNP-+70TA/TC/GC);Amplified products were digested overnight at 37℃ with restriction endonucleases HinfI and StyI,respectively,and separated on8% polyacrylamide gels.Homozygous lines with the TGMS allele(RNZm) cannot be digested by these two restriction enzymes; on the other hand,homozygous wild type lines with the alleles of RNZtc or RNZgc,can be digested completely by HinfI and StyI,respectively; heterozygous genotypes,RNZm/RNZtc and RNZm/RNZgc,can be digested incompletely by Hinf I and Stye I,respectively.By using these functional molecular markers,the PGMS(lnc Rm) and TGMS(RNZm) genes were identified in commercial EGMS lines that had been utilized in the two-line hybrid rice system.Meanwhile,the transition of P/TGMS genes utilized in two-line hybrid rice production in China(1993-2012) was analyzed according to the information of pedigree and growing area.【Result】Out of the47 EGMS lines derived from the PGMS line Nongken 58 S,12 lines carry the PGMS gene lnc Rm,29 lines have the TGMS gene RNZm,two lines carry both genes,while the remaining four lines contain none of them.All 18 lines derived from Annong S-1 and Zhu 1S carry RNZm gene.All P/TGMS descendants from crosses between a Nongken 58 S derivative(Pei'ai 64S) and Annong S-1 carry RNZm gene.In the two lines derived from Pei'ai 64 S and Zhu 1S,one carries both genes,the other has RNZm gene.In addition,in 16 EGMS lines with EGMS progenitors independent from Nongken 58 S,Annong S-1 and Zhu 1S,six of them have lnc Rm,nine of them have RNZm gene,while one of them contains neither lnc Rm nor RNZm gene.A pedigree map with P/TGMS genes was drawn for 92 EGMS lines,including derivatives from Nongken 58 S,Annong S-1,Zhu 1S and others.Furthermore,the transition from lnc Rm-based to RNZm-based two-line hybrid rice production was shown after examination of statistics data of the two-line hybrid rice planting area during 1993-2012,with the RNZm-based hybrids occupying 95% planting area in the two-line hybrid rice production in 2012.【Conclusion】The study systematically revealed the P/TGMS genes in commercial EGMS rice and the presence of discrepancy between pedigree of EGMS lines and their P/TGMS gene.The spontaneous emergence of RNZm can be the reason for the transition from PGMS to TGMS in some EGMS lines derived from Nongken 58 S.EGMS lines with RNZm currently dominate the two-line hybrid rice production in China.

Abstract In plants, male sterility can be caused either by mitochondrial genes with coupled nuclear genes or by nuclear genes alone; the resulting conditions are known as cytoplasmic male sterility (CMS) and genic male sterility (GMS), respectively. CMS and GMS facilitate hybrid seed production for many crops and thus allow breeders to harness yield gains associated with hybrid vigor (heterosis). In CMS, layers of interaction between mitochondrial and nuclear genes control its male specificity, occurrence, and restoration of fertility. Environment-sensitive GMS (EGMS) mutants may involve epigenetic control by noncoding RNAs and can revert to fertility under different growth conditions, making them useful breeding materials in the hybrid seed industry. Here, we review recent research on CMS and EGMS systems in crops, summarize general models of male sterility and fertility restoration, and discuss the evolutionary significance of these reproductive systems.

近年来, 我国两系杂交水稻快速发展, 截止2010年底, 共有427个两系组合通过审定。两系杂交水稻已经奠定了在我国水稻生产中的重要地位, 而光温敏核不育系是两系杂交水稻的基础。本文从实用性角度研究了1994年以来通过审定和获得新品种保护权的两系组合所涉及的130个光温敏核不育系, 分析了光温敏核不育系的基本来源和其中126个不育系的系谱。以原始光温敏核不育系为起点演绎了不育系之间的衍生关系, 介绍了大面积应用及获得新品种保护权的73个不育系的系谱, 归纳了新光温敏核不育系的育成途径。讨论了不育系育性转换的光温反应类型与其核不育基因来源的关系。提出利用光温敏核不育系开展分子生物学研究过程中, 有必要通过系谱分析不育系之间的衍生关系, 对不育系材料进行有针对性的选择。强调了促进光温敏核不育资源的开放与共享, 对加快实用性光温敏核不育系的选育, 积极应对两系杂交稻制种环境的变化具有重要的意义。

近年来, 我国两系杂交水稻快速发展, 截止2010年底, 共有427个两系组合通过审定。两系杂交水稻已经奠定了在我国水稻生产中的重要地位, 而光温敏核不育系是两系杂交水稻的基础。本文从实用性角度研究了1994年以来通过审定和获得新品种保护权的两系组合所涉及的130个光温敏核不育系, 分析了光温敏核不育系的基本来源和其中126个不育系的系谱。以原始光温敏核不育系为起点演绎了不育系之间的衍生关系, 介绍了大面积应用及获得新品种保护权的73个不育系的系谱, 归纳了新光温敏核不育系的育成途径。讨论了不育系育性转换的光温反应类型与其核不育基因来源的关系。提出利用光温敏核不育系开展分子生物学研究过程中, 有必要通过系谱分析不育系之间的衍生关系, 对不育系材料进行有针对性的选择。强调了促进光温敏核不育资源的开放与共享, 对加快实用性光温敏核不育系的选育, 积极应对两系杂交稻制种环境的变化具有重要的意义。

Abstract In flowering plants, sink tissues rely on transport of carbohydrates from photosynthetic tissues (sources) for nutrition and energy. However, how sugar partitioning in plants is regulated at the molecular level during development remains unknown. We have isolated and characterized a rice (Oryza sativa) mutant, carbon starved anther (csa), that showed increased sugar contents in leaves and stems and reduced levels of sugars and starch in floral organs. In particular, the csa mutant had reduced levels of carbohydrates in later anthers and was male sterile. The csa mutant had reduced accumulation of (14)C-labeled sugars in anther sink tissue. CSA was isolated by map-based cloning and was shown to encode an R2R3 MYB transcription factor that was expressed preferentially in the anther tapetal cells and in the sugar-transporting vascular tissues. In addition, the expression of MST8, encoding a monosaccharide transporter, was greatly reduced in csa anthers. Furthermore, CSA was found to be associated in vivo and in vitro with the promoter of MST8. Our findings suggest that CSA is a key transcriptional regulator for sugar partitioning in rice during male reproductive development. This study also establishes a molecular model system for further elucidation of the genetic control of carbon partitioning in plants.

Rice is a major staple food worldwide. Making hybrid rice has proved to be an effective strategy to significantly increase grain yield. Current hybrid rice technologies rely on male sterile lines and have been used predominantly in indica cultivars. However, intrinsic problems exist in the implementation of these technologies, such as limited germplasms and unpredictable conversions from sterility to fertility in the field. Here, we describe a photoperiod-controlled male sterile line, carbon starved anther (csa), which contains a mutation in an R2R3 MYB transcription regulator of pollen development. This mutation was introduced into indica and japonica rice, and it rendered male sterility under short-day conditions and male fertility under long-day conditions in both lines. Furthermore, F(1) plants of csa and a restorer line JP69 exhibited heterosis (hybrid vigor), suggesting the feasibility of using this mutation to create hybrid rice. The csa-based photoperiod-sensitive male sterile line allows the establishment of a stable two-line hybrid system, which promises to have a significant impact on agriculture.

TGMS (thermo-sensitive genic male-sterile) rice is widely used in hybrid rice production. Because of a specific temperature requirement, it can be used only in a narrow rice-growing zone in Asia. A newly discovered reverse thermo-sensitive genic male-sterile line, J207S, has an opposite phynotype compared to the normal TGMS lines. J207S is completely sterile when the temperature is lower than 31 C. Thus, it can be widely used in a larger area. Genetic analysis indicated that the sterility of J207S was controlled by a single recessive gene which was first named as rtms1 . An F 2 population from the cross between J207S and E921 was developed and used for molecular mapping of the rtms1 gene. The AFLP (amplified fragment length polymorphism) technique, combined with BSA (bulked segregant analysis), was used to screen markers linked to the target gene, and eight polymorphic AFLP loci were identified. Co-segregating analysis using the F 2 population showed that two of them, Rev1 and Rev7, were closely linked to the target gene with a recombinant rate of 3.8% and 7.7%, respectively. Both Rev1 and Rev7 were found to be single-copy sequences through Southern analysis. Rev1 was subsequently mapped on chromosome 10 with a doubled-haploid mapping populations derived from the cross CT9993 -IR62266 available at Texas Tech University. RM222 and RG257 were linked to Rev1 at a distance of 11.8 cM and 4.6 cM, respectively. Additional SSR markers from the rice map of Cornell University, RFLP markers from the map of RGP in Japan and the map of Texas Tech University were selected from the region surrounding Rev1 on chromosome 10 to conduct the fine-mapping of the rtms1 gene. Presently, rtms1 was mapped between RM239 and RG257 with genetic distance of 3.6 cM and 4.0 cM, respectively. The most-closely linked AFLP marker, Rev1, 4.2 cM from the rtms1 gene, was sequenced and converted into a SCAR (sequence characterized amplified region) marker which could facilitate marker-assisted selection of the rtms1 gene.

本研究通过形态学、生态学、遗传学及基因定位研究表明,玉米温敏 不育系琼6Qms和琼68S是两种完全不同的玉米温敏不育系,琼6Qms的育性主要表现为颖壳不开裂,育性转换主要受温度影响,该性状由两对隐性重叠不育 基因控制,分别位于第3和第5染色体上.琼68S为花药败育型,其育性转换受温度控制,不育性由一对隐性基因控制,该基因位于第2染色体上.

本研究通过形态学、生态学、遗传学及基因定位研究表明,玉米温敏 不育系琼6Qms和琼68S是两种完全不同的玉米温敏不育系,琼6Qms的育性主要表现为颖壳不开裂,育性转换主要受温度影响,该性状由两对隐性重叠不育 基因控制,分别位于第3和第5染色体上.琼68S为花药败育型,其育性转换受温度控制,不育性由一对隐性基因控制,该基因位于第2染色体上.

以玉米温敏型核雄性不育近等位基因系琼42Qms(不育)和琼42(可育)为材料,通过跟踪解剖、显微观察确定了雄穗处于小花分化期为分离纯化mRNA的最佳时期,以琼42Qms的mRNA作检测样本(Tester)、琼42的mRNA作参照样本(Driver)进行抑制消减杂交,构建差异表达消减cDNA文库.从文库中选取10个cDNA片段作探针,与琼42Qms和琼42的小花分化期雄穗总RNA进行Northern杂交,获得一个仅在琼42Qms中特异表达的差异cDNA片段.以该片段作探针与琼42Qms小花分化期、抽穗成熟期的叶片和雄穗的总RNA进行Northern杂交,结果表明,该片段只在琼42Qms小花分化期的雄穗总RNA中有杂交信号,说明该片段是与核雄性不育相关的.

以玉米温敏型核雄性不育近等位基因系琼42Qms(不育)和琼42(可育)为材料,通过跟踪解剖、显微观察确定了雄穗处于小花分化期为分离纯化mRNA的最佳时期,以琼42Qms的mRNA作检测样本(Tester)、琼42的mRNA作参照样本(Driver)进行抑制消减杂交,构建差异表达消减cDNA文库.从文库中选取10个cDNA片段作探针,与琼42Qms和琼42的小花分化期雄穗总RNA进行Northern杂交,获得一个仅在琼42Qms中特异表达的差异cDNA片段.以该片段作探针与琼42Qms小花分化期、抽穗成熟期的叶片和雄穗的总RNA进行Northern杂交,结果表明,该片段只在琼42Qms小花分化期的雄穗总RNA中有杂交信号,说明该片段是与核雄性不育相关的.

通过不同生态点的育性试验,观察了光敏小麦雄性不育系A31的育性变异,并结合各试验点的光温条件,分析了A31在7个不同生态点的自交结实率.结果表明,A31雄性育性随日长增加有明显的下降趋势,日长是影响其育性的主导因素,在相近日长条件下,温度对A31育性也有一定的影响;A31育性转换的临界日长约为14.5 h.对光敏雄性不育系A31与恢复系1376杂交F2分离群体育性的研究表明,582株F2分离群体的平均结实率为42.16%,变异范围为0～86.67%,由于受异源胞质的影响,F2群体中可育株的平均自交结实率低于恢复系1376的平均结实率.卡方测验表明,F2群体的育性分离符合1对基因的分离比例,所以A31光敏育性可能是由1对基因所控制.

通过不同生态点的育性试验,观察了光敏小麦雄性不育系A31的育性变异,并结合各试验点的光温条件,分析了A31在7个不同生态点的自交结实率.结果表明,A31雄性育性随日长增加有明显的下降趋势,日长是影响其育性的主导因素,在相近日长条件下,温度对A31育性也有一定的影响;A31育性转换的临界日长约为14.5 h.对光敏雄性不育系A31与恢复系1376杂交F2分离群体育性的研究表明,582株F2分离群体的平均结实率为42.16%,变异范围为0～86.67%,由于受异源胞质的影响,F2群体中可育株的平均自交结实率低于恢复系1376的平均结实率.卡方测验表明,F2群体的育性分离符合1对基因的分离比例,所以A31光敏育性可能是由1对基因所控制.

以选育的小麦(Triticum aestivum L.)温光敏核不育系C412S为试材,以C412S回交转育时的受体亲本C412为常规品系对照,通过分期播种试验研究了其育性转换特性.用涂抹压片法观察减数分裂和小孢子发育进程,用半定量RT-PCR技术分析不育与可育条件下不同发育时期的幼穗中腺嘌呤磷酸核糖基转移酶基因(APRT)的表达水平.结果表明,通过调整播种期改变雄性发育的温光条件,C412S表现出完全不育一高不育-半不育一正常可育的育性转换特性.C412S花粉败育的高峰在单核小孢子晚期,主要表现圆败型不育.C412S的育性敏感期是从花粉母细胞形成期到成熟花粉期.其中最敏感的时段是花粉母细胞形成期到减数分裂期.与对照相比,C412S的APRT1基因序列有个别碱基变异,但编码氨基酸序列没有变化.在花粉母细胞形成期至单核期,与晚播可育条件相比,早播不育的C412S幼穗中APRT基因转录水平下调,因此认为,其育性转换与幼穗中APRT基因转录水平有一定关系.

以选育的小麦(Triticum aestivum L.)温光敏核不育系C412S为试材,以C412S回交转育时的受体亲本C412为常规品系对照,通过分期播种试验研究了其育性转换特性.用涂抹压片法观察减数分裂和小孢子发育进程,用半定量RT-PCR技术分析不育与可育条件下不同发育时期的幼穗中腺嘌呤磷酸核糖基转移酶基因(APRT)的表达水平.结果表明,通过调整播种期改变雄性发育的温光条件,C412S表现出完全不育一高不育-半不育一正常可育的育性转换特性.C412S花粉败育的高峰在单核小孢子晚期,主要表现圆败型不育.C412S的育性敏感期是从花粉母细胞形成期到成熟花粉期.其中最敏感的时段是花粉母细胞形成期到减数分裂期.与对照相比,C412S的APRT1基因序列有个别碱基变异,但编码氨基酸序列没有变化.在花粉母细胞形成期至单核期,与晚播可育条件相比,早播不育的C412S幼穗中APRT基因转录水平下调,因此认为,其育性转换与幼穗中APRT基因转录水平有一定关系.

为了研究温敏不育系在可育和不育温度条件下的花粉发育情况，通过人工控温的方法对YS型小麦温敏不育系A3017-310和A3017-312减数分裂期分别处在不育和可育温度条件下的花粉育性进行了分析．结果表明，不育温度条件（12～16℃）下，花粉粒多数败育，I2-KI染色不着色，染色不均匀，约1／3花粉粒发育至单核中后期或双核早期发生败育，大部分花粉粒发育到二核后期或三核期发生败育（染败），两个系的花粉粒碘染败育率分别为98．7％和99．0％，花粉萌发势分别为0．7％和0．5％，花药不开裂、不散粉，自交结实率均为0；可育温度条件下（正常分蘖穗为18～22℃，再生分蘖穗为20～25℃），花粉粒多数正常，花药能正常开裂、散粉，花粉粒在这两种可育温度条件下碘染的败育率无差异，均约为20％．花粉萌发势随温度升高而增加，A3017—310由60．7％增为71.5％。A3017-312由27．4％提高为63．1％;自交结实率（国际法）为34．6％～113．7％。A3017—310和A3017—312株系来源于同一组合的F6代，它们在不同的可育条件下，育性恢复程度有所不同，表明YS型温敏不育系在育性转换为可育后控制自交结实的遗传机制较为复杂。

为了研究温敏不育系在可育和不育温度条件下的花粉发育情况，通过人工控温的方法对YS型小麦温敏不育系A3017-310和A3017-312减数分裂期分别处在不育和可育温度条件下的花粉育性进行了分析．结果表明，不育温度条件（12～16℃）下，花粉粒多数败育，I2-KI染色不着色，染色不均匀，约1／3花粉粒发育至单核中后期或双核早期发生败育，大部分花粉粒发育到二核后期或三核期发生败育（染败），两个系的花粉粒碘染败育率分别为98．7％和99．0％，花粉萌发势分别为0．7％和0．5％，花药不开裂、不散粉，自交结实率均为0；可育温度条件下（正常分蘖穗为18～22℃，再生分蘖穗为20～25℃），花粉粒多数正常，花药能正常开裂、散粉，花粉粒在这两种可育温度条件下碘染的败育率无差异，均约为20％．花粉萌发势随温度升高而增加，A3017—310由60．7％增为71.5％。A3017-312由27．4％提高为63．1％;自交结实率（国际法）为34．6％～113．7％。A3017—310和A3017—312株系来源于同一组合的F6代，它们在不同的可育条件下，育性恢复程度有所不同，表明YS型温敏不育系在育性转换为可育后控制自交结实的遗传机制较为复杂。

为了建立技术简便、成本低廉的二系杂交小麦种子生产体系 ,选育适应范围广泛的温敏不育系 ,采用多点分期播种和分期剪穗再生分蘖等方法 ,调查分析了小麦温度敏感不育系 A3314的育性转换条件 ,结果表明:A3314在中国黄淮冬麦区、云贵冬麦区、西北春麦区、东北春麦区各点 ,按当地小麦生产正季播种均表现稳定雄性不育 ,雄性不育的安全播种期达60d左右;而在黄淮和云贵冬麦区春播、夏播则自交结实 ,适宜条件下自交结实率可达60%以上。杨陵 10期分期播种和 8期分期剪穗再生分蘖的育性与各期孕穗至开花期间的日平均气温、空气相对湿度、日长的关系分析表明 :A3314的育性具有温度敏感特性 ;孕穗期前后 8d,即减数分裂至单核期 ,是其育性转换的敏感时期 ,此期处于 >18.3℃温度条件下 ,A3314则由雄性不育转换为可育 ;育性转换与日长无显著相关 ;在敏感期>18℃的可育环境下 ,自交结实率与 40%～80%范围内的空气相对湿度呈显著正相关。根据 A 3314的温敏特性 ,推测它在中国大部分小麦产区均可安全用于杂交小麦制种。

为了建立技术简便、成本低廉的二系杂交小麦种子生产体系 ,选育适应范围广泛的温敏不育系 ,采用多点分期播种和分期剪穗再生分蘖等方法 ,调查分析了小麦温度敏感不育系 A3314的育性转换条件 ,结果表明:A3314在中国黄淮冬麦区、云贵冬麦区、西北春麦区、东北春麦区各点 ,按当地小麦生产正季播种均表现稳定雄性不育 ,雄性不育的安全播种期达60d左右;而在黄淮和云贵冬麦区春播、夏播则自交结实 ,适宜条件下自交结实率可达60%以上。杨陵 10期分期播种和 8期分期剪穗再生分蘖的育性与各期孕穗至开花期间的日平均气温、空气相对湿度、日长的关系分析表明 :A3314的育性具有温度敏感特性 ;孕穗期前后 8d,即减数分裂至单核期 ,是其育性转换的敏感时期 ,此期处于 >18.3℃温度条件下 ,A3314则由雄性不育转换为可育 ;育性转换与日长无显著相关 ;在敏感期>18℃的可育环境下 ,自交结实率与 40%～80%范围内的空气相对湿度呈显著正相关。根据 A 3314的温敏特性 ,推测它在中国大部分小麦产区均可安全用于杂交小麦制种。

The cytoplasmic male sterile (CMS) wheat ( Triticum aestivum L.) line KTP116A developed at Northwest A&F University, Yangling, China, was sterile at temperatures below 18°C and fertile at temperatures above 20°C during Zadok’s growth stages 45–52. The possibility of a two-line system has a promising future for hybrid wheat production. The present study describes morphological differences in pollen abortion behavior at different temperatures, and the genetics of the thermo-sensitive restorer gene(s) in line KTP116A. Cytological observations showed that abnormalities in development of male sterile anthers first appeared at the bi-nucleate stage. Only a few pollen grains go through the second mitosis to produce two sperm cells; most of those became abnormal pollen grains and shell structures without protoplast, confirming that the conversion from sterility to fertility in the CMS line was accompanied by changes in morphology and cytology. A BC 1 population of 198 plants from a cross of male-sterile KTP116A and male fertile F 1 TP116B/WM5-5 was developed to study the genetic control of thermo-sensitive sterility. Chi squared tests on data from back-crossed populations revealed that two recessive genes, designated rfv 1 sp and rfv 2, were responsible for sterility of line KTP116A. Sixteen of 712 SSR markers were polymorphic between the parents and bulks. Four SSR markers, viz. Xgwm11 , Xgwm18 , Xgwm413 and Xbarc137 , were linked to thermo-sensitive gene rfv 1 sp on chromosome 1BS of T. spelta, and another four markers were linked to rfv 2 located on chromosome 2A. This thermo-sensitive male sterile line can be used for production of experimental hybrids in order to test levels of heterosis.

小麦杂种优势利用研究，在半个世纪的工作基础上，近年来发展迅速并取得了突破性进展。为此，1997年8月“国际玉米小麦改良中心”（CIMMYT，墨西哥）将小麦杂种优势利用列入今后大幅度提高小麦产量的二个主要途径之一，正加速研究。1998年12月在北京召开...

小麦杂种优势利用研究，在半个世纪的工作基础上，近年来发展迅速并取得了突破性进展。为此，1997年8月“国际玉米小麦改良中心”（CIMMYT，墨西哥）将小麦杂种优势利用列入今后大幅度提高小麦产量的二个主要途径之一，正加速研究。1998年12月在北京召开...

The photo-thermo-sensitive male sterile (PTMS) wheat line BS20 showed male sterility under short-day photoperiod and low temperature conditions. Photo-thermo-controlled growth chambers were used to study the fertility alteration characteristics of PTMS wheat line BS20. The period of photo-sensitivity and thermo-sensitivity was coincident with the pollen development stages from pollen mother cell (PMC) formation to mono-nucleate. Fertility alteration of BS20 was induced mainly by temperature, and the critical point of temperature was 10–12 66 C. Below the critical temperature, BS20 remained sterile and was not affected by photoperiod. However, above the critical temperature, the fertility of BS20 improved as the temperature rose. In the temperature range of 12–14 66 C the fertility of BS20 improved significantly as the photoperiod extended.

BS20-T is a thermo-sensitive genic male sterile (TGMS) wheat line ( Triticum aestivum L.) used in hybrid wheat breeding in northern China. BS20-T was crossed with common wheat variety ZN7. F 1 plants were highly fertile. The segregation ratio of male fertile and male sterile individuals in F 2 and BC 1 F 1 plants were close to 3:1 and 1:1, respectively. Other crosses of BS20-T also segregated for a single gene. Bulked sergeant analysis with SSR markers indicated the sterility gene was located on chromosome 2BL. It was named tmsBS20T. Screening of 162 extremely sterile and 30 extremely fertile F 2 plants with linked markers indicated flanking by gwm403 and gwm374 with genetic distances of 2.2 and 4.5cM, respectively. tmsBS20T was transferred into several common wheat varieties by using traditional hybridization combined with marker assisted selection with these two markers. Further identification of derived TGMS lines is ongoing.

In this study, we reported the repaid construction of a molecular marker linkage map of rice ( Oryza sativa L.). An F 2 population from the cross between Annong S_1 and Nanjing 11 was used to construct a genetic linkage map of rice. Total of 142 newly screened AFLP markers and 30 anchor markers (25 SSR markers and 5 RFLP markers) were mapped on the 12 chromosomes covering 1 537.4 cM of rice genome. The average interval between these markers was 9.0 cM. The total work which usually was finished in more than one year was finished within only 3 months by one person. This is the first plant AFLP map developed in China. A new thermosensitive genic male sterile gene in rice, tms5, was tigged and mapped onto chromosome 2 during the development of the linkage map.

Thermosensitive genic male-sterile (TGMS) lines, which are male-sterile at restrictive (high) temperatures but male-fertile at permissive (low) temperatures, have been widely used in breeding two-line hybrid rice (Oryza sativa L.). Here we find that mutation of thermosensitive genic male sterile 5 (tms5) in rice causes the TGMS trait through a loss of RNase Z(S1) function. We show that RNase Z(S1) processes the mRNAs of three ubiquitin fusion ribosomal protein L40 (UbL40) genes into multiple fragments in vitro and in vivo. In tms5 mutants, high temperature results in increased levels of UbL40 mRNAs. Overaccumulation of UbL40 mRNAs causes defective pollen production and male sterility. Our results uncover a novel mechanism of RNase Z(S1)-mediated UbL40 mRNA regulation and shows that loss of this regulation produces TGMS in rice, a finding with potential applications in hybrid crop breeding.

Photoperiod-thermo-sensitive genic male sterile (PTGMS) rice exhibits a number of desirable traits for hybrid rice production. The cloning genes responsible for PTGMS and those elucidating male sterility mechanisms and reversibility to fertility would be of great significance to provide a foundation to develop new male sterile lines. Guangzhan63S, a PTGMS line, is one of the most widely used indica two-line hybrid rice breeding systems in China. In this study, genetic analysis based on F(2) and BC(1)F(2) populations derived from a cross between Guangzhan63S and 1587, determined a single recessive gene controls male sterility in Guangzhan63S. Molecular marker techniques combined with bulked-segregant analysis (BSA) were used and located the target gene (named ptgms2-1) between two SSR markers RM12521 and RM12823. Fine mapping of the ptgms2-1 locus was conducted with 45 new Insertion-Deletion (InDel) markers developed between the RM12521 and RM12823 region, using 634 sterile individuals from F(2) and BC(1)F(2) populations. Ptgms2-1 was further mapped to a 50.4 kb DNA fragment between two InDel markers, S2-40 and S2-44, with genetic distances of 0.08 and 0.16 cM, respectively, which cosegregated with S2-43 located on the AP004039 BAC clone. Ten genes were identified in this region based on annotation results from the RiceGAAS system. A nuclear ribonuclease Z gene was identified as the candidate for the ptgms2-1 gene. This result will facilitate cloning the ptgms2-1 gene. The tightly linked markers for the ptgms2-1 gene locus will further provide a useful tool for marker-assisted selection of this gene in rice breeding programs.

【Objective】The objective of this study is to identify and reveal the transition of the male sterile gene(s) in photoperiod- and temperature-sensitive genic male sterile (P/TGMS) lines utilized in the two-line hybrid rice system in China.【Method】A total of 90 environment-conditioned genic male sterile (EGMS) lines including descendents of Nonken 58S, Annong S-1 and Zhu 1S, were used in the present study. Genomic DNAs were extracted from rice leaves by modified CTAB. One functional CAPS marker based on the C to G mutation in the long non-coding RNA (lncR) gene was designed for PGMS genotyping; Namely, a pair of primers NK-F (5'-ATCCCACAAATCCTTTAGCA-3') and NK-R (5'-CCGTTATAGATAGACCCGAGA-3') were used to amplify segments harboring the mutation site, followed by digestion overnight at 37℃ with restriction endonuclease RsaⅠ and separation on 1% agarose gel electrophoresis. Homozygous PGMS allele (lncR^m) (329 bp) can be readily distinguished from homozygous wild type (lncR^wt) (414 bp) and heterozygous type (lncR^m/lncR^wt) (414 and 329 bp) based on the sizes of digestion products. For TGMS genotyping, functional dCAPS markers were deployed with the following steps: Two pairs of primers RNZ1F (5'-ACCGCGCCGCCACCGGGTCGGCCGGAG-3')/RNZR (5'-TGAAGAGGAACTCCTGCGAGACGG-3'), RNZ2F (5'-ACCGC GCCGCCACCGGGTCGGCCCAAG-3')/RNZR were used to amplify segments harboring the mutation site (SNP-^+70TA/TC/GC); Amplified products were digested overnight at 37℃ with restriction endonucleases HinfⅠand StyⅠ, respectively, and separated on 8% polyacrylamide gels. Homozygous lines with the TGMS allele (RNZ^m) cannot be digested by these two restriction enzymes; on the other hand, homozygous wild type lines with the alleles of RNZ^tc or RNZ^gc, can be digested completely by HinfⅠ and StyⅠ, respectively; heterozygous genotypes, RNZ^m/RNZ^tc and RNZ^m/RNZ^gc, can be digested incompletely by HinfⅠand StyⅠ, respectively. By using these functional molecular markers, the PGMS (lncR^m) and TGMS (RNZ^m) genes were identified in commercial EGMS lines that had been utilized in the two-line hybrid rice system. Meanwhile, the transition of P/TGMS genes utilized in two-line hybrid rice production in China (1993-2012) was analyzed according to the information of pedigree and growing area. 【Result】Out of the 47 EGMS lines derived from the PGMS line Nongken 58S, 12 lines carry the PGMS gene lncR^m, 29 lines have the TGMS gene RNZ^m, two lines carry both genes, while the remaining four lines contain none of them. All 18 lines derived from Annong S-1 and Zhu 1S carry RNZ^m gene. All P/TGMS descendants from crosses between a Nongken 58S derivative (Pei"ai 64S) and Annong S-1 carry RNZ^m gene. In the two lines derived from Pei"ai 64S and Zhu 1S, one carries both genes, the other has RNZ^m gene. In addition, in 16 EGMS lines with EGMS progenitors independent from Nongken 58S, Annong S-1 and Zhu 1S, six of them have lncR^m, nine of them have RNZ^m gene, while one of them contains neither lncR^m nor RNZ^m gene. A pedigree map with P/TGMS genes was drawn for 92 EGMS lines, including derivatives from Nongken 58S, Annong S-1, Zhu 1S and others. Furthermore, the transition from lncR^m-based to RNZ^m-based two-line hybrid rice production was shown after examination of statistics data of the two-line hybrid rice planting area during 1993-2012, with the RNZ^m-based hybrids occupying ＞95% planting area in the two-line hybrid rice production in 2012. 【Conclusion】The study systematically revealed the P/TGMS genes in commercial EGMS rice and the presence of discrepancy between pedigree of EGMS lines and their P/TGMS gene. The spontaneous emergence of RNZ^m can be the reason for the transition from PGMS to TGMS in some EGMS lines derived from Nongken 58S. EGMS lines with RNZ^m currently dominate the two-line hybrid rice production in China.

【Objective】The objective of this study is to identify and reveal the transition of the male sterile gene(s) in photoperiod- and temperature-sensitive genic male sterile (P/TGMS) lines utilized in the two-line hybrid rice system in China.【Method】A total of 90 environment-conditioned genic male sterile (EGMS) lines including descendents of Nonken 58S, Annong S-1 and Zhu 1S, were used in the present study. Genomic DNAs were extracted from rice leaves by modified CTAB. One functional CAPS marker based on the C to G mutation in the long non-coding RNA (lncR) gene was designed for PGMS genotyping; Namely, a pair of primers NK-F (5'-ATCCCACAAATCCTTTAGCA-3') and NK-R (5'-CCGTTATAGATAGACCCGAGA-3') were used to amplify segments harboring the mutation site, followed by digestion overnight at 37℃ with restriction endonuclease RsaⅠ and separation on 1% agarose gel electrophoresis. Homozygous PGMS allele (lncR^m) (329 bp) can be readily distinguished from homozygous wild type (lncR^wt) (414 bp) and heterozygous type (lncR^m/lncR^wt) (414 and 329 bp) based on the sizes of digestion products. For TGMS genotyping, functional dCAPS markers were deployed with the following steps: Two pairs of primers RNZ1F (5'-ACCGCGCCGCCACCGGGTCGGCCGGAG-3')/RNZR (5'-TGAAGAGGAACTCCTGCGAGACGG-3'), RNZ2F (5'-ACCGC GCCGCCACCGGGTCGGCCCAAG-3')/RNZR were used to amplify segments harboring the mutation site (SNP-^+70TA/TC/GC); Amplified products were digested overnight at 37℃ with restriction endonucleases HinfⅠand StyⅠ, respectively, and separated on 8% polyacrylamide gels. Homozygous lines with the TGMS allele (RNZ^m) cannot be digested by these two restriction enzymes; on the other hand, homozygous wild type lines with the alleles of RNZ^tc or RNZ^gc, can be digested completely by HinfⅠ and StyⅠ, respectively; heterozygous genotypes, RNZ^m/RNZ^tc and RNZ^m/RNZ^gc, can be digested incompletely by HinfⅠand StyⅠ, respectively. By using these functional molecular markers, the PGMS (lncR^m) and TGMS (RNZ^m) genes were identified in commercial EGMS lines that had been utilized in the two-line hybrid rice system. Meanwhile, the transition of P/TGMS genes utilized in two-line hybrid rice production in China (1993-2012) was analyzed according to the information of pedigree and growing area. 【Result】Out of the 47 EGMS lines derived from the PGMS line Nongken 58S, 12 lines carry the PGMS gene lncR^m, 29 lines have the TGMS gene RNZ^m, two lines carry both genes, while the remaining four lines contain none of them. All 18 lines derived from Annong S-1 and Zhu 1S carry RNZ^m gene. All P/TGMS descendants from crosses between a Nongken 58S derivative (Pei"ai 64S) and Annong S-1 carry RNZ^m gene. In the two lines derived from Pei"ai 64S and Zhu 1S, one carries both genes, the other has RNZ^m gene. In addition, in 16 EGMS lines with EGMS progenitors independent from Nongken 58S, Annong S-1 and Zhu 1S, six of them have lncR^m, nine of them have RNZ^m gene, while one of them contains neither lncR^m nor RNZ^m gene. A pedigree map with P/TGMS genes was drawn for 92 EGMS lines, including derivatives from Nongken 58S, Annong S-1, Zhu 1S and others. Furthermore, the transition from lncR^m-based to RNZ^m-based two-line hybrid rice production was shown after examination of statistics data of the two-line hybrid rice planting area during 1993-2012, with the RNZ^m-based hybrids occupying ＞95% planting area in the two-line hybrid rice production in 2012. 【Conclusion】The study systematically revealed the P/TGMS genes in commercial EGMS rice and the presence of discrepancy between pedigree of EGMS lines and their P/TGMS gene. The spontaneous emergence of RNZ^m can be the reason for the transition from PGMS to TGMS in some EGMS lines derived from Nongken 58S. EGMS lines with RNZ^m currently dominate the two-line hybrid rice production in China.

The thermo-sensititve genic male-sterile (TGMS) gene in rice can alter fertility in response to temperature and is useful in the two-line system of hybrid rice production. However, little is known about the TGMS gene at the molecular level. The objective of this study was to identify molecular markers tightly linked with the TGMS gene and to map the gene onto a specific rice chromosome. Bulked segregant analysis of an F 2 population from 5460s (a TGMS mutant line) x ong Wan 52 was used to identify RAPD markers linked to the rice TGMS gene. Four hundred RAPD primers were screened for polymorphisms between the parents and between two bulks representing fertile and sterile plants; of these, 4 primers produced polymorphic products. Most of the polymorphic fragments contained repetitive sequences. Only one singlecopy sequence fragment was found, a 1.2-kb fragment amplified by primer OPB-19 and subsequently named TGMS1.2. TGMS1.2 was mapped on chromosome 8 with a RIL population and confirmed by remapping with a DHL population. Segregation analysis using TGMS1.2 as a probe indicated that TGMS1.2 both consegregated and was lined with the TGMS gene in this population. It is located about 6.7 cM from the TGMS gene. As TGMS1.2 is linked to the TGMS gene, the TGMS gene must be located on chromosome 8.

ABSTRACT Environment-sensitive genic male sterility (EGMS) Iine is useful in hybrid rice seed production. A parental line of rice, Norin-PL12, has a thermosensitive genic male sterility (TGMS) gene, tms-2. We estimated the locus of tms-2 using RFLP markers in F2 population derived from a cross between Norin-PL12 and Aus variety, Dular. As a result of quantitative trait locus (QTL) analysis using RFLP markers, it was revealed that the tms-2 is located between R643A and R1440 on chromosome 7.

The thermosensitive genetic male sterility (TGMS) system is considered to be a more efficient alternative to the cytoplasmic male sterility () system for hybrid . An F2 population from a cross between a TGMS mutant line (IR32364TGMS) and IR68 was used to map the TGMS gene tms3(t). Fertile and sterile bulks were constructed following the classification of F2 into true breeding sterile, fertile, and segregating fertile based on F3 family studies. From the survey of 389 arbitrary primers in bulked segregant analysis, four RAPD markers were identified in which three, OPF182600, OPB19750, and OPAA7550, were linked to tms3(t) in repulsion phase and one, OPAC3640, was linked to tms3(t) in coupling phase. The tms3(t) gene was flanked by OPF182600 and OPAC3640 on one side and by OPAA7550 and OPB19750 on the other side. All four markers were low-copy sequences and two of them (OPF182600 and OPAC3640) detected polymorphism when the markers were used to probe the genomic blots. Subsequently, OPAC3640 was mapped to the short arm of 6 using a mapping population available at IRRI. However, no RFLP markers from this region showed linkage to tms3(t) owing to the lack of polymorphism between the parents. All RAPD fragments were cloned and partially sequenced from both ends. Thus, PCR primers can be designed to develop PCR markers for marker-assisted breeding to facilitate the transfer of tms3(t) from one genetic background to another.

The discovery and application of the thermosensitive genic male sterility (TGMS) system has great potential for revolutionizing hybrid seed production technology in rice. Use of the TGMS system in two-line breeding is simple, inexpensive, efficient, and eliminates the limitations associated with the cytoplasmic-genetic male sterility (CMS) system. An F 2 population developed from a cross between a TGMS indica mutant, TGMS–VN1, and a fertile indica line, CH1, was used to identify molecular markers linked to the TGMS gene and to subsequently determine its chromosomal location on the linkage map of rice. Bulk segregant analysis was performed using the AFLP technique. From the survey02of 200 AFLP primer combinations, four AFLP markers (E2/M5–600, E3/M16–400, E5/M12–600, and E5/M12–200) linked to the TGMS gene were identified. All the markers were linked to the gene in the coupling phase. All except E2/M5–200 were found to be low-copy sequences. However, the marker E5/M12–600 showed polymorphism in RFLP analysis and was closely linked to the TGMS gene at a distance of 3.3 cM. This marker was subsequently mapped on chromosome 2 using doubled-haploid mapping populations derived from the crosses IR64×Azucena and CT9993×IR62666, available at IRRI, Philippines, and Texas Tech University, respectively. Linkage of microsatellite marker RM27 with the TGMS gene further confirmed its location on chromosome 2. The closest marker, E5/M12–600, was sequenced so that a PCR marker can be developed for the marker-assisted transfer of this gene to different genetic backgrounds. The new TGMS gene is tentatively designated as tms4(t).

The application of genetic male sterility in hybrid rice production has great potential to revolutionize hybrid seed production methodology. The two-line breeding system by using thermo-sensitive genic male sterility (TGMS) has been discovered and successfully developed as a breeding strategy in rice. One TGMS gene was investigated by a spontaneous rice mutant line, Sokcho-MS, originated from a Korean japonica variety. It was shown that Sokcho-MS is completely sterile at a temperature higher than 27 degrees C and/or lower than 25 degrees C during the development of spikelets, but fertile at the temperature ranging from 25 to 27 degrees C regardless of the levels of day-length. Genetic analysis and molecular mapping based on SSR, STS and EST markers revealed that a single recessive gene locus involved the control of genic male sterility in Sokcho-MS. By using an F2 mapping population derived from a cross between Sokcho-MS and a fertile indica variety Neda, the new TGMS gene, designated as tms6, was mapped primarily to the long arm of chromosome 5 of Oryza sativa at the interval between markers E60663 (2.0 cM) and RM440 (5.8 cM). Subsequently, tms6 was fine mapped to the interval between markers RM3351 (0.1 cM) and E60663 (1.9 cM). As tms6 appeared to be independent of other mapped TGMS genes in rice, the genetic basis of Sokcho-MS was further discussed.

Photoperiod-sensitive genic male-sterile rice has a number of desirable characteristics for hybrid rice production. Previous studies identified pms1, located on chromosome 7, as a major locus for photoperiod-sensitive genic male sterility. The objective of this study was to localize the pms1 locus to a specific DNA fragment by genetic and physical mapping. Using 240 highly sterile individuals and a random sample of 599 individuals from an F2 population of over 5000 individuals from a cross between Minghui 63 and 32001S, we localized the pms1 locus by molecular marker analysis to a genetic interval of about 4 cM, 0.25 cM from RG477 on one side and 3.8 cM from R1807 on the other side. A contig map composed of seven BAC clones spanning approximate 500 kb in length was constructed for the pms1 region by screening a BAC library of Minghui 63 DNA using RFLP markers and chromosomal walking. Analysis of recombination events in the pms1 region among the highly sterile individuals reduced the length of the contig map to three BAC clones. Sequencing of one BAC clone, 2109, identified two SSR markers located 85 kb apart in the clone that flanked the pms1 locus on both sides, as indicated by the distribution of recombination events. We thus concluded that the pms1 locus was located on the fragment bounded by the two SSR markers.

Photoperiod-sensitive genic male-sterile (PSGMS) rice, in which pollen fertility is regulated by day-length, originally arose as a natural mutant in the rice cultivar Nongken 58 ( Oryza sativa ssp. japonica ). Previous studies identified pms3 on chromosome 12 as the locus of the original PSGMS mutation. In this study we have assigned the pms3 locus to a 28.4-kb DNA fragment by genetic and physical mapping. A cross between Nongken 58S (PSGMS line) and DH80 was used to produce an F 2 population of about 7000 plants, from which 892 highly sterile individuals were obtained for recombination analysis. By analyzing recombination events in the sterile individuals using a total of 157 RFLP probes from a BAC contig covering the pms3 region, the pms3 locus was localized to a sub-region of less than 1.7cM. Further analysis of recombination events using 49 additional probes isolated from this sub-region identified markers flanking the pms3 region on each side; these markers are only 28.4-kb apart. Sequence analysis of this fragment predicted the presence of five ORFs, found high homology with two ESTs in public databases, and detected three SNPs between the mutant and the wild-type parents, which may be helpful for identifying a candidate gene for pms3 .

The reverse photoperiod-sensitive genic male sterility (PGMS) and thermo-sensitive genic male sterility (TGMS) lines have an opposite phenotype compared with normal PGMS and TGMS lines widely used by the two-line system in current hybrid rice seed production. Thus, the application of reverse PGMS and TGMS lines can compensate PGMS and TGMS lines in hybrid rice production. YiD1S is a reverse PGMS line, in which pollen fertility is mainly regulated by day-length, but also influenced by temperature. Genetic analysis indicated that male sterility of YiD1S was controlled by two recessive major genes . An F 2 population from a cross between YiD1S and 8528 was developed and used for molecular mapping of the two reverse PGMS genes which were first named rpms1 and rpms2 . Both simple sequence repeat (SSR) markers and bulked segregant analysis (BSA) were used in this study. As a result, one reverse PGMS gene ( rpms1 ) was mapped to the interval between SSR markers RM22980 (0.9cM) and RM23017 (1.8cM) on chromosome 8. Eight SSR markers, YDS818, RM22984, RM22986, RM22997, YDS816, RM23002, RM339 and YDS810 completely co-segregated with the rpms1 gene. Another reverse PGMS gene ( rpms2 ) was mapped to the interval between SSR markers RM23898 (0.9cM) and YDS926 (0.9cM) on chromosome 9. The physical mapping information from publicly available resources shows that the rpms1 and rpms2 loci are located in a region of 998 and 68kb, respectively. The analysis based on marker genotypes showed that the effect of rpms1 was slightly larger than that of rpms2 and that the two genes interacted in controlling male sterility.

Abstract The present study describes a novel thermo-sensitive genic male sterile (TGMS) line, Qiong68ms. To analyse the mode of fertility inheritance and tag the TGMS gene, a set of F2, BC1 and F(2:3) populations derived from a cross between Qiong68ms and K12 were evaluated for a period of 2 years. Classical genetic analyses and QTL mapping using the mean restoration percentage of the F(2:3) populations revealed that the fertility of Qiong68ms was likely to be governed by a single recessive gene, which was named tms3; the tms3 gene was mapped to a location between SSR markers umc2129 and umc1041, at a distance of 3.7 cM form umc2129 and 1.5 cM form umc1041. The molecular markers tightly linked with tms3 gene will aid in the transfer of the TGMS gene to various background inbred lines using the MAS method.

A thermo-sensitive genic male-sterile (TGMS) wheat line ( Triticum aestivum L.) BNY-S was obtained from the spontaneous mutant of BNY-F. Its fertility was decided by the temperature during the differentiation stage of the spikelets. BNY-S was completely sterile when the temperature was lower than 10 degrees C during the differentiation stage of the spikelets, but fertile when the temperature was higher than 10 degrees C. Genetic analysis indicated that the sterility of BNY-S was controlled by a single recessive gene, which was named as wtms1. An F(2) population, consisting of 3,000 individuals from the cross between BNY-S and Lankao 52-24, was used for genetic analysis and statistical analysis of the TGMS and, out of them, 158 sterile and 93 fertile extremes were present for molecular tagging and mapping of the wtms1 gene. SSR (simple sequence repeat) and AFLP (amplified fragment length polymorphism) techniques combined with BSA (bulked segregant analysis) were used to screen markers linked to the target gene. As a result, wtms1 was preliminarily mapped on chromosome 2B according to SSR analysis. In AFLP analysis, 14 polymorphic AFLP loci were identified with a linkage relation to the wtms1 gene. Then linkage analysis using the F(2) population showed that three of them, E: AAG/M: CTA(163), E: AGG/M: CTC(220) and E: ACA/M: CTA(160), were linked to the wtms1 gene relatively close to a genetic distance of 6.9 cM, 6.9 cM and 13.9 cM, respectively. Finally, the wtms1 gene was mapped between the SSR marker Xgwm 374 and the AFLP marker E: AAG/M: CTA(163) with the distance of 4.8 cM and 6.9 cM, respectively. A partial linkage map was constructed according the SSR and AFLP data.

YM型小麦温敏雄性不育系的不育基因被定位在1Bs染色体片段上, 但已发现的相邻分子标记与该基因的遗传距离较大, 达10 cM以上。为寻找与该基因连锁更紧密的分子标记, 以YM型温敏雄性不育系ATM3314与恢复系中国春杂交的F₂代200株为作图群体, 从1Bs的22个SSR引物中筛选出5个在亲本和F₂代中分离的SSR引物, 构建了1个包含5个标记的1Bs局部遗传连锁图谱。结合F₂代个体的育性调查, 采用复合区间作图法在YM型温敏雄性不育系的1Bs染色体上检测到不育基因的1个主效QTL<em>rfv1-1</em>和1个微效QTL<em>rfv1-2</em>。<em>rfv1-1</em>位于SSR标记Xgwm18和Xwmc406之间, 与两标记的遗传距离分别为6.0 cM和4.6 cM, LOD值为8.80, 加性效应23.87, 显性效应10.44, 可解释表型变异的23.91%; <em>rfv1-2</em>位于Xwmc406和Xbarc8之间, 与两标记的遗传距离分别为4.0 cM和3.4 cM, LOD值为3.10, 加性效应17.59, 显性效应5.99, 可解释表型变异的7.78%。本研究初步定位了YM型小麦温敏雄性不育系1Bs染色体片段上不育基因的QTL, 为进一步准确定位该基因奠定了基础。

YM型小麦温敏雄性不育系的不育基因被定位在1Bs染色体片段上, 但已发现的相邻分子标记与该基因的遗传距离较大, 达10 cM以上。为寻找与该基因连锁更紧密的分子标记, 以YM型温敏雄性不育系ATM3314与恢复系中国春杂交的F₂代200株为作图群体, 从1Bs的22个SSR引物中筛选出5个在亲本和F₂代中分离的SSR引物, 构建了1个包含5个标记的1Bs局部遗传连锁图谱。结合F₂代个体的育性调查, 采用复合区间作图法在YM型温敏雄性不育系的1Bs染色体上检测到不育基因的1个主效QTL<em>rfv1-1</em>和1个微效QTL<em>rfv1-2</em>。<em>rfv1-1</em>位于SSR标记Xgwm18和Xwmc406之间, 与两标记的遗传距离分别为6.0 cM和4.6 cM, LOD值为8.80, 加性效应23.87, 显性效应10.44, 可解释表型变异的23.91%; <em>rfv1-2</em>位于Xwmc406和Xbarc8之间, 与两标记的遗传距离分别为4.0 cM和3.4 cM, LOD值为3.10, 加性效应17.59, 显性效应5.99, 可解释表型变异的7.78%。本研究初步定位了YM型小麦温敏雄性不育系1Bs染色体片段上不育基因的QTL, 为进一步准确定位该基因奠定了基础。

农大3338是通过多年鉴定发现的一个优良的光温敏核雄性不 育小麦品系，运用SSR和ISSR两种分子标记对其光温敏核雄性不育基因进行了定位，检测到 了两个光温敏核雄性不育基因座位，并分别命名为 ptms1和ptms2，其中ptms 1的基因效应是ptms2 的2～3倍。

农大3338是通过多年鉴定发现的一个优良的光温敏核雄性不 育小麦品系，运用SSR和ISSR两种分子标记对其光温敏核雄性不育基因进行了定位，检测到 了两个光温敏核雄性不育基因座位，并分别命名为 ptms1和ptms2，其中ptms 1的基因效应是ptms2 的2～3倍。

Male sterility of wheat-breeding line 337S (Triticum aestivum L.) is sensitive to both short day-length/low temperature and long day-length/high temperature. 337S was crossed with the common wheat variety, Huamai No. 8 and the F1 was highly fertile. The F2 population segregated in a 15:1 ratio for fertility/sterility in 243 individuals under long day-length/high-temperature. The two thermophotoperiod-responsive male sterile genes were mapped to chromosomes 5B and 2B using Simple Sequence Repeat (SSR) markers and bulked segregant analysis. Partial linkage maps around the sterility loci of chromosomes 2B and 5B were constructed using the 243 individuals in the F2 population. One gene (wptms1) for male sterility was flanked by the SSR markers Xgwm335 and Xgwm371 at a genetic distance in chromosome 5B of 4.1 and 24.4 cM, respectively. The second gene (wptms2) was mapped between markers Xgwm374 and Xgwm120 at a genetic distance of 6.6 and 20.9 cM, respectively. The closest linked markers Xgwm335 (wptms1) and Xgwm374 (wptms2) explained 53 and 38% of phenotypic variation for the fertility. The SSR markers provide a useful tool to transfer the male sterile genes into elite wheat germplasm.

Utilization of a two-line breeding system via photoperiod-thermo sensitive male sterility has a great potential for hybrid production in wheat (Triticum aestivum L.).337S is a novel wheat male sterile line sensitive to both short daylength/low temperature and long daylength/high temperature.Five F2 populations derived from the crosses between 337S and five common wheat varieties were developed for genetic analysis.All F1's were highly fertile while segregation occurred in the F2 populations with a ratio of 3 fertile:1 sterile under short daylength/low temperature.It is shown that male sterility in 337S was controlled by a single recessive gene,temporarily designated as wptms3.Bulked segregant analysis (BSA) coupled with simple sequence repeat (SSR) markers was applied to map the sterile gene using one mapping population.The wptms3 gene was mapped to chromosome arm 1BS and flanked by Xgwm413 and Xgwm182 at a genetic distance of 3.2 and 23.5 cM,respectively.The accuracy and efficiency of marker-assisted selection were evaluated and proved essential for identifying homozygous recessive male sterile genotypes of the wptms3 gene in F2 generation.

为明确小麦红叶耳基因的染色体位置,以小麦BS210(红叶耳)/O;201(绿叶耳)的DH群体为材料,于2005～2006和2006～2007年度分别将120个DH株系及亲本在北京种植,并对该群体进行叶耳颜色的鉴定.遗传和方差分析表明,红叶耳由一对主效基因控制,同时受环境影响,并存在基因与环境互作效应;根据DH群体叶耳颜色分别构建红叶耳池和绿叶耳池,利用BSA法和SSR引物筛选与红叶耳基因连锁的标记,将红叶耳相关基因定位于38染色体长臂上,QTL分析表明,红叶耳主效QTL位于WMC182和WMC54之间,贡献率为24.1%,与最近标记WMC182的距离为7.1 cM,红叶耳基因来自母本BS210.本研究结果还表明,BSA与QTL方法相结合,有利于提高简单性状基因定位的效率和精确度.

为明确小麦红叶耳基因的染色体位置,以小麦BS210(红叶耳)/O;201(绿叶耳)的DH群体为材料,于2005～2006和2006～2007年度分别将120个DH株系及亲本在北京种植,并对该群体进行叶耳颜色的鉴定.遗传和方差分析表明,红叶耳由一对主效基因控制,同时受环境影响,并存在基因与环境互作效应;根据DH群体叶耳颜色分别构建红叶耳池和绿叶耳池,利用BSA法和SSR引物筛选与红叶耳基因连锁的标记,将红叶耳相关基因定位于38染色体长臂上,QTL分析表明,红叶耳主效QTL位于WMC182和WMC54之间,贡献率为24.1%,与最近标记WMC182的距离为7.1 cM,红叶耳基因来自母本BS210.本研究结果还表明,BSA与QTL方法相结合,有利于提高简单性状基因定位的效率和精确度.

雄性不育系40A是由核基因和环境条件互作而致的光温敏雄性不育 新品系.对其在不同播期下的育性表现及F1杂种优势的研究结果表明:该不育系早播表现为雄性可育(武汉地区在10月20日以前播种),晚播表现为雄性不育 (武汉地区在12月上、中旬播种).与多个测交恢复系配制的F1杂种育性完全正常,具有较强的杂种优势.

雄性不育系40A是由核基因和环境条件互作而致的光温敏雄性不育 新品系.对其在不同播期下的育性表现及F1杂种优势的研究结果表明:该不育系早播表现为雄性可育(武汉地区在10月20日以前播种),晚播表现为雄性不育 (武汉地区在12月上、中旬播种).与多个测交恢复系配制的F1杂种育性完全正常,具有较强的杂种优势.

利用谷子光敏不育源292为父本，与不同生态类型的优良品种进行有性杂交，经多代选择，从杂交组合坝谷239×292中，选育出光（温）敏不育系821。研究表明：（1）长日照诱导不育，短日照诱导可育，幼穗生长锥伸长至雌雄蕊分化期为光诱导育性转换敏感期。（2）温度对育性的有效作用时期在四分体时期，短日照下温度作用显著，长日照下温度作用不显著。（3）不育性由一对隐性核基因控制。（4）在张家口为代表的春谷区，长日照15h条件下分期播种821，没有可育期；在河北省南部自然光温环境下，早播为不育期，晚播为可育期。

利用谷子光敏不育源292为父本，与不同生态类型的优良品种进行有性杂交，经多代选择，从杂交组合坝谷239×292中，选育出光（温）敏不育系821。研究表明：（1）长日照诱导不育，短日照诱导可育，幼穗生长锥伸长至雌雄蕊分化期为光诱导育性转换敏感期。（2）温度对育性的有效作用时期在四分体时期，短日照下温度作用显著，长日照下温度作用不显著。（3）不育性由一对隐性核基因控制。（4）在张家口为代表的春谷区，长日照15h条件下分期播种821，没有可育期；在河北省南部自然光温环境下，早播为不育期，晚播为可育期。

光温敏雄性不育现象是作物杂种优势利用的新途径之一,谷子光温敏两系杂交种的应用使得谷子产量大幅度提高。目前,主要杂交谷子品种的母本是谷子光温敏雄性不育系A2。采用四因素（播期、密度、底肥、追肥）正交试验设计,在海南省三亚市对其南繁高产技术进行了研究。结果表明：除播期对不育系A2产量有极显著影响外,其他因素对产量影响均不显著。正交试验产量结果显示,12月5日播种、种植密度60万株/hm-2、底肥施用量150.0 kg/hm-2、追肥施用量150.0 kg/hm-2条件下,谷子光温敏雄性不育系A2繁种产量最高,达到了438.30 kg/hm-2。本研究结果可为不育系A2南繁高产技术的制订提供基础数据。

光温敏雄性不育现象是作物杂种优势利用的新途径之一,谷子光温敏两系杂交种的应用使得谷子产量大幅度提高。目前,主要杂交谷子品种的母本是谷子光温敏雄性不育系A2。采用四因素（播期、密度、底肥、追肥）正交试验设计,在海南省三亚市对其南繁高产技术进行了研究。结果表明：除播期对不育系A2产量有极显著影响外,其他因素对产量影响均不显著。正交试验产量结果显示,12月5日播种、种植密度60万株/hm-2、底肥施用量150.0 kg/hm-2、追肥施用量150.0 kg/hm-2条件下,谷子光温敏雄性不育系A2繁种产量最高,达到了438.30 kg/hm-2。本研究结果可为不育系A2南繁高产技术的制订提供基础数据。

1987年我们在(材5&times;测35-1)杂交后代中发现一雄性不育材料"292",它具有随光周期变化而育性发生转换的特点.在长日照(14.5小时)条件下,植株表现雄性不育,其不育度为99.4%,不育株率为100%;而在短日照(11.2小时)条件下,表现雄性可育.经测配我们认为属于谷子隐性核不育材料,是国内首次发现,为谷子杂种优势利用开辟了一条新途径,在作物育种理论上也具有重要价值.

1987年我们在(材5&times;测35-1)杂交后代中发现一雄性不育材料"292",它具有随光周期变化而育性发生转换的特点.在长日照(14.5小时)条件下,植株表现雄性不育,其不育度为99.4%,不育株率为100%;而在短日照(11.2小时)条件下,表现雄性可育.经测配我们认为属于谷子隐性核不育材料,是国内首次发现,为谷子杂种优势利用开辟了一条新途径,在作物育种理论上也具有重要价值.

1987年在显性核不育材料&ldquo;宁黄A&rdquo;中获得一雄性不育材料,表现在长日照(14.5小时/日)条件下雄性不育,在短日照(11.2小时/日)条件下雄性可育.关于谷子光敏型显性核不育材料,国内外尚未见报道,它的发现为谷子显性核不育材料的利用开辟了新途径,在理论研究及杂种优势利用方面都颇有价值.

1987年在显性核不育材料&ldquo;宁黄A&rdquo;中获得一雄性不育材料,表现在长日照(14.5小时/日)条件下雄性不育,在短日照(11.2小时/日)条件下雄性可育.关于谷子光敏型显性核不育材料,国内外尚未见报道,它的发现为谷子显性核不育材料的利用开辟了新途径,在理论研究及杂种优势利用方面都颇有价值.

以谷子光敏雄性不育材料“6 83”为不育源 ,选育出 4个新光敏不育系SMPA1～SMPA4 ,与“6 83”相比 ,其农艺性状有明显改善 ,且SMPA2、SMPA3的抽穗期接近本生态区品种类型 ,便于利用 ;光敏不育特性的遗传特点待进一步研究。通过测配 ,筛选出铁谷 1号、98 391等一批光敏不育恢复系 ,以及以SMPA1～SMPA4为不育系初步选出了SMPA1× 98 391等 3个强优组合。

以谷子光敏雄性不育材料“6 83”为不育源 ,选育出 4个新光敏不育系SMPA1～SMPA4 ,与“6 83”相比 ,其农艺性状有明显改善 ,且SMPA2、SMPA3的抽穗期接近本生态区品种类型 ,便于利用 ;光敏不育特性的遗传特点待进一步研究。通过测配 ,筛选出铁谷 1号、98 391等一批光敏不育恢复系 ,以及以SMPA1～SMPA4为不育系初步选出了SMPA1× 98 391等 3个强优组合。

<P>谷子不育系异交结实率低严重制约着杂交种大面积应用于生产。本研究证明柱头外露程度与异交结实率呈显著正相关（r<SUB>0.001</SUB>=0.9597**）。山西省农业科学院经济作物研究所成功选育出谷子光敏雄性不育突变系“81-16”，其不育度为100%，异交结实率达61%。用植物形态解剖学方法证明，“81-16”雌蕊生活力强，柱头完全外露，接受花粉的有效面积大，是其异交结实率高的主要原因。本文还提出应重视母本柱头性状选育，并加强谷子杂交种制种技术研究。</P>

<P>谷子不育系异交结实率低严重制约着杂交种大面积应用于生产。本研究证明柱头外露程度与异交结实率呈显著正相关（r<SUB>0.001</SUB>=0.9597**）。山西省农业科学院经济作物研究所成功选育出谷子光敏雄性不育突变系“81-16”，其不育度为100%，异交结实率达61%。用植物形态解剖学方法证明，“81-16”雌蕊生活力强，柱头完全外露，接受花粉的有效面积大，是其异交结实率高的主要原因。本文还提出应重视母本柱头性状选育，并加强谷子杂交种制种技术研究。</P>

经过多年的研究，我所选育出了 世界上第一个以温敏为主的秋不育型“湘糯粱Ｓ－１”糯高粱两用不育系，所配制的杂交组合已在生产上应用。1991年试种25亩，1992年试种200余 亩，1993年试种示范2500亩。全国十余省试种示范结果，亩产一般400公斤在右，最高亩产可达650公斤以上，表现出较广的适应性和较强的杂种优 势。本文重点对该两用不育系稳定不育的光温条件、育性转换敏感期、温度临界值及分子机理进行探讨和分析。我们在研究中发现，该不育系无论在细胞核、叶绿体 及线粒体蛋白中均比可育材料多一个9zKD的多肽；不育材料叶、穗的过氧化物酶活性高；在叶绿体全蛋白的电泳图谱上，该不育系与可育材料位于55KD的条 带（1,5－二磷酸核酮糖羧化酶大亚基）的浓度存在差异。

经过多年的研究，我所选育出了 世界上第一个以温敏为主的秋不育型“湘糯粱Ｓ－１”糯高粱两用不育系，所配制的杂交组合已在生产上应用。1991年试种25亩，1992年试种200余 亩，1993年试种示范2500亩。全国十余省试种示范结果，亩产一般400公斤在右，最高亩产可达650公斤以上，表现出较广的适应性和较强的杂种优 势。本文重点对该两用不育系稳定不育的光温条件、育性转换敏感期、温度临界值及分子机理进行探讨和分析。我们在研究中发现，该不育系无论在细胞核、叶绿体 及线粒体蛋白中均比可育材料多一个9zKD的多肽；不育材料叶、穗的过氧化物酶活性高；在叶绿体全蛋白的电泳图谱上，该不育系与可育材料位于55KD的条 带（1,5－二磷酸核酮糖羧化酶大亚基）的浓度存在差异。

本研究主要针对两系高粱在生产应用过程中受严格的温光条件制约，种子生产需要在特定生态点、特定时期进行，且可能出现育性的不稳定性等问题，采用人工气候室处理、大田试验、同工酶和蛋白质分析等方法，研究了两系高粱不育系的纯化稳定特性；两系高粱不育系育性转换的温光敏感时期；温度对两系高粱不育系育性转换的影响；光周期对两系不育系育性转换的影响以及育性转换的分子机理。主要结果如下： 1．两系高粱不育系“湘糯粱2S”在孕穗至抽穗期控温25℃情况下表现出稳定不育，不育株率和不育度均达100％，利用控温26℃处理后仍表现出不育的植株，砍秆再生，再生植株在28℃以上高温条件下抽穗转为可育，自交繁殖出了纯化稳定的不育系种子，对照“湘糯粱S-1”在控温25℃时即表现为可育。 2．“湘糯粱2S”育性转换的温光敏感时期为花粉母细胞形成至减数分裂期，其外形判断为旗叶叶环高出倒2叶叶环0-8厘米，即抽穗前4-10天(秋季)或3-7天(夏季)。 3．“湘糯粱2S”是一个低温不育、高温可育的温敏型不育系，其育性转换的临界温度为25℃。 4．光周期对“湘糯粱2S”育性转换有一定的促进作用，即在一定温度范围内表现出短日促进不育，长日促进可育，但不存在明显的临界光周期。 5.“湘糯粱2S”在海南三亚生态点进行冬季制种，播种期可安 排在9月卜句至11月下旬，控制抽穗期在11月下旬至1月卜句，此 时段育性表现稳定，不育株率达100%，不育度达99.8%以上。在湖南 凤凰高海拔生态点进行夏季制种，播种期适宜安排在6月_上旬，于8 月中下旬抽穗，此时育性表现稳定，不育株率达98.6%，不育度达 98.2%。在湖南长沙生态点进行繁殖，播种期适宜安排在4月下旬至 5月底，7月中旬至8月中旬抽穗，此时段日平均温度达28℃以上， 育性表现为可育或半育。 6.经同工酶和蛋白质电泳分析，“湘糯粱2S”不育材料过氧化物 酶活性比可育材料高，不育材料比可育材料多一个92KD的多肤。表 明这种不育性可能是一种受光温调节的雄性可育基因表达受到阻碍 而使花粉走向败育。

本研究主要针对两系高粱在生产应用过程中受严格的温光条件制约，种子生产需要在特定生态点、特定时期进行，且可能出现育性的不稳定性等问题，采用人工气候室处理、大田试验、同工酶和蛋白质分析等方法，研究了两系高粱不育系的纯化稳定特性；两系高粱不育系育性转换的温光敏感时期；温度对两系高粱不育系育性转换的影响；光周期对两系不育系育性转换的影响以及育性转换的分子机理。主要结果如下： 1．两系高粱不育系“湘糯粱2S”在孕穗至抽穗期控温25℃情况下表现出稳定不育，不育株率和不育度均达100％，利用控温26℃处理后仍表现出不育的植株，砍秆再生，再生植株在28℃以上高温条件下抽穗转为可育，自交繁殖出了纯化稳定的不育系种子，对照“湘糯粱S-1”在控温25℃时即表现为可育。 2．“湘糯粱2S”育性转换的温光敏感时期为花粉母细胞形成至减数分裂期，其外形判断为旗叶叶环高出倒2叶叶环0-8厘米，即抽穗前4-10天(秋季)或3-7天(夏季)。 3．“湘糯粱2S”是一个低温不育、高温可育的温敏型不育系，其育性转换的临界温度为25℃。 4．光周期对“湘糯粱2S”育性转换有一定的促进作用，即在一定温度范围内表现出短日促进不育，长日促进可育，但不存在明显的临界光周期。 5.“湘糯粱2S”在海南三亚生态点进行冬季制种，播种期可安 排在9月卜句至11月下旬，控制抽穗期在11月下旬至1月卜句，此 时段育性表现稳定，不育株率达100%，不育度达99.8%以上。在湖南 凤凰高海拔生态点进行夏季制种，播种期适宜安排在6月_上旬，于8 月中下旬抽穗，此时育性表现稳定，不育株率达98.6%，不育度达 98.2%。在湖南长沙生态点进行繁殖，播种期适宜安排在4月下旬至 5月底，7月中旬至8月中旬抽穗，此时段日平均温度达28℃以上， 育性表现为可育或半育。 6.经同工酶和蛋白质电泳分析，“湘糯粱2S”不育材料过氧化物 酶活性比可育材料高，不育材料比可育材料多一个92KD的多肤。表 明这种不育性可能是一种受光温调节的雄性可育基因表达受到阻碍 而使花粉走向败育。

以回18A为母本、抗蚜保持系130B为父本,回交8个世代育成 夏播高粱不育系冀130A.在选育过程中发现,冀130A的不育度受温度影响.为进一步了解温度对该不育系育性的影响,明确影响育性的临界温度,为杂交制 种提供依据,对其进行了播期试验、异地种植和关键时期不同温度处理试验,结果表明:旗叶伸展至抽穗期间平均气温低于23℃,不育度为100％,株间无差 异；平均气温高于23℃,部分花粉可育,随着温度升高,可育花粉增多,平均气温超过26℃可明显观察到可育花粉,自交结实率可达30％,株间有差异.通过 石蜡制片及显微摄影观察,对不同温度处理条件下花药和花粉特征进行了研究.结果显示:低温导致绒毡层细胞出现明显异常,主要表现为液泡化、径向肥大和延迟 退化；低温条件下早期败育的花药,造孢细胞或花粉母细胞较早出现解体,无单核花粉粒产生.旗叶伸展至抽穗期间温度高于26℃时,花粉母细胞减数分裂形成单 核花粉粒,之后部分花粉粒出现畸形,但仍有约40％的正常花粉粒可以存活到花药开裂并散粉.低温导致绒毡层细胞出现异常,是花粉败育的主要原因.冀 130A的育成,扩大了高粱不育系的差异,有利于商业化的高粱杂交种选育,同时为深入研究高粱不育系的败育机理提供了新种质资源.对冀130A育性转换特 性研究为利用该不育系进行杂交种制种选择制种区域和播期奠定了基础.

以回18A为母本、抗蚜保持系130B为父本,回交8个世代育成 夏播高粱不育系冀130A.在选育过程中发现,冀130A的不育度受温度影响.为进一步了解温度对该不育系育性的影响,明确影响育性的临界温度,为杂交制 种提供依据,对其进行了播期试验、异地种植和关键时期不同温度处理试验,结果表明:旗叶伸展至抽穗期间平均气温低于23℃,不育度为100％,株间无差 异；平均气温高于23℃,部分花粉可育,随着温度升高,可育花粉增多,平均气温超过26℃可明显观察到可育花粉,自交结实率可达30％,株间有差异.通过 石蜡制片及显微摄影观察,对不同温度处理条件下花药和花粉特征进行了研究.结果显示:低温导致绒毡层细胞出现明显异常,主要表现为液泡化、径向肥大和延迟 退化；低温条件下早期败育的花药,造孢细胞或花粉母细胞较早出现解体,无单核花粉粒产生.旗叶伸展至抽穗期间温度高于26℃时,花粉母细胞减数分裂形成单 核花粉粒,之后部分花粉粒出现畸形,但仍有约40％的正常花粉粒可以存活到花药开裂并散粉.低温导致绒毡层细胞出现异常,是花粉败育的主要原因.冀 130A的育成,扩大了高粱不育系的差异,有利于商业化的高粱杂交种选育,同时为深入研究高粱不育系的败育机理提供了新种质资源.对冀130A育性转换特 性研究为利用该不育系进行杂交种制种选择制种区域和播期奠定了基础.

对棉花光温敏雄性不育系湘QB研究初步表明，在湖南省常德地区7-8月，该材料在日光照时数13.5 h以上和日平均温度24.1℃以上的气候条件下表现为不育.有较广的棉花雄性不育性温度空间，适合棉花不去雄人工授粉杂交制种，杂种优势得到充分利用.

对棉花光温敏雄性不育系湘QB研究初步表明，在湖南省常德地区7-8月，该材料在日光照时数13.5 h以上和日平均温度24.1℃以上的气候条件下表现为不育.有较广的棉花雄性不育性温度空间，适合棉花不去雄人工授粉杂交制种，杂种优势得到充分利用.

以新育种材料特棉S-1为供试材料,研究了特棉S-1在自然生态条件下的生长发育规律、日平均气温对特棉S-1育性转换影响、不同气温条件下特棉S-1育性转换规律、光照长短对特棉S-1育性转换影响、不同授粉时间对特棉S-1成铃率影响等方面的内容。主要结果如下: 1 根据所记载的株式图,在自然生态条件下对特棉S-1生长发育规律的研究结果为:各处理从播种到出苗所需的时间一致,一般为4～5天,从出苗到现蕾一般为30～50天。同一处理不同植株间的出苗、现蕾日期相近,从出苗到现蕾所需的时间播期早的处理要比播期迟的处理所需时间长。每一处理内各植株之间的开花时期没有明显差异,一般表现为7月15日从第一、二果枝的第二果节开始出现不育,不育期一直维持到8月23～25日,不育有效期为42天左右。 2 日平均气温是对特棉S-1育性转换影响的主要因素。从所记载的株式图可知,特棉S-1表现出雄性完全不育的起始时间一般出现在连续8天日平均气温达27.8℃之后。根据棉花花芽分化阶段规律分析,实际上在棉花花粉出现不育的前八日高温期间,已经影响了棉花的育性,同时将其与当地的气象资料结合分析可得:在2002～2004年的6月下旬至8月下旬之间,27～28℃出现的频率最大,且≥27℃的频率在三年总频率中占82.4%。 在特棉S-1出现不育之前连续五日、七日、十日滑动日平均气温分别为:27.4℃、27.4℃、27.5℃,通过对上述滑动平均气温分析得出的结果为:它们对特棉S-1育性转换的影响与日平均气温对特棉S-1育性转换的影响相似。 通过对大田相对湿度的调查、分析得出相对湿度不是特棉S-1育性转换主要影响因素。 3 特棉S-1不育期的长短随着外界气候条件的变化而变化。通过近3年来的大田试验观察,初步掌握了特棉S-1在长沙地区育性转换时间变化规律:该不育系不育的始期一般在7月上、中旬,终止期在8月下旬。不同的年份始止期不一致,但不育性状持续时间变化较小,其持续时间一般为42天,在此期间为特棉S-1最安全的杂交制种时间。 4 在大田中,对还未出现不育的棉株进行连续14天的遮光处理。分别测出外界下午8种光照强度出现的时间,并与对照植株进行比较。根据所观测到的数据资料进行统计、分析,同时结合所处理植株开花、育性状况的变化情况可得:

以新育种材料特棉S-1为供试材料,研究了特棉S-1在自然生态条件下的生长发育规律、日平均气温对特棉S-1育性转换影响、不同气温条件下特棉S-1育性转换规律、光照长短对特棉S-1育性转换影响、不同授粉时间对特棉S-1成铃率影响等方面的内容。主要结果如下: 1 根据所记载的株式图,在自然生态条件下对特棉S-1生长发育规律的研究结果为:各处理从播种到出苗所需的时间一致,一般为4～5天,从出苗到现蕾一般为30～50天。同一处理不同植株间的出苗、现蕾日期相近,从出苗到现蕾所需的时间播期早的处理要比播期迟的处理所需时间长。每一处理内各植株之间的开花时期没有明显差异,一般表现为7月15日从第一、二果枝的第二果节开始出现不育,不育期一直维持到8月23～25日,不育有效期为42天左右。 2 日平均气温是对特棉S-1育性转换影响的主要因素。从所记载的株式图可知,特棉S-1表现出雄性完全不育的起始时间一般出现在连续8天日平均气温达27.8℃之后。根据棉花花芽分化阶段规律分析,实际上在棉花花粉出现不育的前八日高温期间,已经影响了棉花的育性,同时将其与当地的气象资料结合分析可得:在2002～2004年的6月下旬至8月下旬之间,27～28℃出现的频率最大,且≥27℃的频率在三年总频率中占82.4%。 在特棉S-1出现不育之前连续五日、七日、十日滑动日平均气温分别为:27.4℃、27.4℃、27.5℃,通过对上述滑动平均气温分析得出的结果为:它们对特棉S-1育性转换的影响与日平均气温对特棉S-1育性转换的影响相似。 通过对大田相对湿度的调查、分析得出相对湿度不是特棉S-1育性转换主要影响因素。 3 特棉S-1不育期的长短随着外界气候条件的变化而变化。通过近3年来的大田试验观察,初步掌握了特棉S-1在长沙地区育性转换时间变化规律:该不育系不育的始期一般在7月上、中旬,终止期在8月下旬。不同的年份始止期不一致,但不育性状持续时间变化较小,其持续时间一般为42天,在此期间为特棉S-1最安全的杂交制种时间。 4 在大田中,对还未出现不育的棉株进行连续14天的遮光处理。分别测出外界下午8种光照强度出现的时间,并与对照植株进行比较。根据所观测到的数据资料进行统计、分析,同时结合所处理植株开花、育性状况的变化情况可得:

为了在生产上更好地利用棉花温敏不育系,采用在自然条件下分期播种和人工定温试验相结合的方 法,研究了棉花温敏不育系TMS-2在湛江制种的可行性.结果表明,TMS-2的雄性育性随着温度的升高而降低,随温度的降低而升高;其育性转换临界温度 为27～28 ℃;其敏感时期是开花前5～15 d;利用TMS-2在湛江6月下旬至7月中旬制种,成功率可达93.1%.

为了在生产上更好地利用棉花温敏不育系,采用在自然条件下分期播种和人工定温试验相结合的方 法,研究了棉花温敏不育系TMS-2在湛江制种的可行性.结果表明,TMS-2的雄性育性随着温度的升高而降低,随温度的降低而升高;其育性转换临界温度 为27～28 ℃;其敏感时期是开花前5～15 d;利用TMS-2在湛江6月下旬至7月中旬制种,成功率可达93.1%.

[Objective] The aim of this study was to finely map and clone the photoperiod-sensitive male sterility gene in upland cotton. [Method] Eleven male parents were crossed with CCRI 9106 (i.e., a novel Gossypium hirsutum L. photoperiod-sensitive male sterile mutant derived from CCRI 040029 using space mutation breeding technology) to evaluate heterosis. The F1 and F2 populations generated from the cross between CCRI 9106 and G. hirsutum L. cv. Letu 603 were used for genetic analyses. A bulked segregant analysis combined with simple sequence repeat (SSR)-based techniques were used to detect markers linked with the male sterility gene. An F2 population (186 plants) from the CCRI 9106 × Letu 603 cross was used for gene mapping analyses. [Results] All F1 plants were fertile, and the segregation ratio of fertility phenotypes in the F2 population was consistent with the 3:1 ratio of Mendelian inheritance. This indicated that male sterility was controlled by a recessive gene. Out of 16 544 SSRs, 18 were linked with the gene. The genetic linkage map suggested that the gene was located on chromosome D12 of the upland cotton genome within markers NAU3442 and CGR6339 , with a 0.2-cM genetic distance to them. This photoperiod-sensitive male sterility gene was named ys-1. [Conclusion] The mapping results for ys-1 may be applicable for the fine-mapping and positional cloning of the photoperiod-sensitive male sterility gene.

[Objective] The aim of this study was to finely map and clone the photoperiod-sensitive male sterility gene in upland cotton. [Method] Eleven male parents were crossed with CCRI 9106 (i.e., a novel Gossypium hirsutum L. photoperiod-sensitive male sterile mutant derived from CCRI 040029 using space mutation breeding technology) to evaluate heterosis. The F1 and F2 populations generated from the cross between CCRI 9106 and G. hirsutum L. cv. Letu 603 were used for genetic analyses. A bulked segregant analysis combined with simple sequence repeat (SSR)-based techniques were used to detect markers linked with the male sterility gene. An F2 population (186 plants) from the CCRI 9106 × Letu 603 cross was used for gene mapping analyses. [Results] All F1 plants were fertile, and the segregation ratio of fertility phenotypes in the F2 population was consistent with the 3:1 ratio of Mendelian inheritance. This indicated that male sterility was controlled by a recessive gene. Out of 16 544 SSRs, 18 were linked with the gene. The genetic linkage map suggested that the gene was located on chromosome D12 of the upland cotton genome within markers NAU3442 and CGR6339 , with a 0.2-cM genetic distance to them. This photoperiod-sensitive male sterility gene was named ys-1. [Conclusion] The mapping results for ys-1 may be applicable for the fine-mapping and positional cloning of the photoperiod-sensitive male sterility gene.

1利用杂种优势育种和制种的现状及问题 1．1人工或化学去雄授粉杂交制种此法技术简单，任何两个品种都可以互为父母本，花期去雄并人工授粉杂交即可．也有利用化学杀雄杂交制种。优点是易充分利用现有品种资源。杂交种选配随意性强，配制组合自由。并且部分组合可以利用F2。缺点是劳动强度大，用工多，成本高，F2的杂交优势较F1多有衰退。

1利用杂种优势育种和制种的现状及问题 1．1人工或化学去雄授粉杂交制种此法技术简单，任何两个品种都可以互为父母本，花期去雄并人工授粉杂交即可．也有利用化学杀雄杂交制种。优点是易充分利用现有品种资源。杂交种选配随意性强，配制组合自由。并且部分组合可以利用F2。缺点是劳动强度大，用工多，成本高，F2的杂交优势较F1多有衰退。

Photoperiod-sensitive genic male sterility (PSGMS) rice has a number of desirable characteristics for hybrid rice production. In this study, we conducted a molecular marker-based mapping and genetic analysis of PSGMS genes using two crosses involving the original mutant Nongken 58S as the PSGMS parent. The genomic locations of the PSGMS loci were determined following the bulked extreme and recessive class approach, in which the regions containing the PSGMS loci were identified by assaying the bulks of extreme phenotypes and the distances between the PSGMS loci and molecular markers were calculated from the highly sterile plants of the F

Phased small-interfering RNAs (phasiRNAs) are a special class of small RNAs, which are generated in 21- or 24-nt intervals from transcripts of precursor RNAs. Although phasiRNAs have been found in a range of organisms, their biological functions in plants have yet to be uncovered. Here we show that phasiRNAs generated by the photopheriod-sensetive genic male sterility 1 (Pms1) locus were associated with photoperiod-sensitive male sterility (PSMS) in rice, a germplasm that started the two-line hybrid rice breeding. The Pms1 locus encodes a long-noncoding RNA PMS1T that was preferentially expressed in young panicles. PMS1T was targeted by miR2118 to produce 21-nt phasiRNAs that preferentially accumulated in the PSMS line under long-day conditions. A single nucleotide polymorphism in PMS1T nearby the miR2118 recognition site was critical for fertility change, likely leading to differential accumulation of the phasiRNAs. This result suggested possible roles of phasiRNAs in reproductive development of rice, demonstrating the potential importance of this RNA class as regulators in biological processes.

Photoperiod-sensitive male sterility (PSMS) is a valuable germplasm for hybrid rice breeding. Recently, we cloned pms3, a locus controlling PSMS, which encodes a long non-coding RNA called LDMAR required for normal male fertility of the rice plant under long-day conditions. Increased methylation in the promoter of LDMAR in the PSMS rice (Nongken 58S) relative to the wild-type (Nongken 58) reduced expression of LDMAR leading to male sterility under long-day conditions. In this study, we identified a siRNA named Psi–LDMAR in the LDMAR promoter region that was more abundant in Nongken 58S than in Nongken 58. We showed that Psi–LDMAR was likely derived from AK111270, a transcript obtained from the sense strand of the LDMAR promoter with its 3’-end having a 110-base overlap with the 5’-end of LDMAR. Overexpressing AK111270 in Nongken 58S greatly enriched Psi–LDMAR, which induced RNA-directed DNA methylation in the LDMAR promoter and repressed the expression of LDMAR. Reduction of LDMAR in Nongken 58S changed the critical day length for fertility recovery and delayed the fertility recovery under short-day conditions. This result added to our understanding of the molecular mechanism for PSMS.

近年来, 我国两系杂交水稻快速发展, 截止2010年底, 共有427个两系组合通过审定。两系杂交水稻已经奠定了在我国水稻生产中的重要地位, 而光温敏核不育系是两系杂交水稻的基础。本文从实用性角度研究了1994年以来通过审定和获得新品种保护权的两系组合所涉及的130个光温敏核不育系, 分析了光温敏核不育系的基本来源和其中126个不育系的系谱。以原始光温敏核不育系为起点演绎了不育系之间的衍生关系, 介绍了大面积应用及获得新品种保护权的73个不育系的系谱, 归纳了新光温敏核不育系的育成途径。讨论了不育系育性转换的光温反应类型与其核不育基因来源的关系。提出利用光温敏核不育系开展分子生物学研究过程中, 有必要通过系谱分析不育系之间的衍生关系, 对不育系材料进行有针对性的选择。强调了促进光温敏核不育资源的开放与共享, 对加快实用性光温敏核不育系的选育, 积极应对两系杂交稻制种环境的变化具有重要的意义。

近年来, 我国两系杂交水稻快速发展, 截止2010年底, 共有427个两系组合通过审定。两系杂交水稻已经奠定了在我国水稻生产中的重要地位, 而光温敏核不育系是两系杂交水稻的基础。本文从实用性角度研究了1994年以来通过审定和获得新品种保护权的两系组合所涉及的130个光温敏核不育系, 分析了光温敏核不育系的基本来源和其中126个不育系的系谱。以原始光温敏核不育系为起点演绎了不育系之间的衍生关系, 介绍了大面积应用及获得新品种保护权的73个不育系的系谱, 归纳了新光温敏核不育系的育成途径。讨论了不育系育性转换的光温反应类型与其核不育基因来源的关系。提出利用光温敏核不育系开展分子生物学研究过程中, 有必要通过系谱分析不育系之间的衍生关系, 对不育系材料进行有针对性的选择。强调了促进光温敏核不育资源的开放与共享, 对加快实用性光温敏核不育系的选育, 积极应对两系杂交稻制种环境的变化具有重要的意义。

AnnongS-1, a thermo-sensitive genic male-sterile (TGMS) rice line, has a new TGMS gene. Genetic analysis indicated that the sterility of AnnongS-1 was controlled by a single resessive gene named tms5. In our previous studies based on an F(2) population from the cross between AnnongS-1 and Nanjing11, tms5 was mapped on chromosome 2. Recently, a RIL (recombinant inbred line) population from the same cross was developed and used for the fine mapping of the tms5 gene. Molecular marker techniques combined with BSA (bulked segregant analysis) were used. As a result, two AFLP markers (AF10, AF8), one RAPD marker (RA4), one STS marker (C365-1), one CAPs marker (G227-1) and four SSR markers (RM279, RM492, RM327, RM324) were found to be closely linked to tms5 gene. The DNA sequences of the RFLP marker of C365 and G227 were found in GenBank, and on the basis of these sequences, many primers were designed to amplify the two parents and their RIL population plants. Finally, the tms5 gene was mapped between STS marker C365-1 and CAPs marker G227-1 at a distance of 1.04 cM from C365-1 and 2.08 cM from G227-1.

本研究利用小麦BS20/Fu3的DH群体的289个系,分别于2005-2006和2006-2007两个年度将该群体种植于北京和安徽阜阳,田间调查挑旗期、抽穗期和结实率情况,采用复合区间作图法,对小麦挑旗期、抽穗期和光温敏核雄性不育性进行QTL分析,研究结果表明: (1)挑旗期共有3个主效QTL,分别位于1BL、1DL和6BL,贡献率为3.34%-15.73%;抽穗期共有4个主效QTL,分别位于1BL、1DL、4AL和6BL染色体上,贡献率为4.93%-19.98%。挑旗期与抽穗期共同的QTL位于1BL、1DL和6BL,分别与cfa2129、cfd65和Xgwm58紧密连锁,与cfa2129的遗传距离为3.05-13.05cM,与cfd65的遗传距离为0.05-2.05cM,与Xgwm58的遗传距离为0.06cM。抽穗期位于4AL上的QTL,只在阜阳两年种植的材料中检测到,与最近标记Barc170的遗传距离为1.7cM-6.1cM,可能由于不同生态环境诱导不同基因的表达。挑旗期和抽穗期的QTL基本一致,推测由于基因的多效性或控制不同性状的基因紧密连锁所致,同时从分子水平验证了两个性状的高度相关性。 (2)利用WinQTLCart和QTLNetwork两个软件分析三种算法的结果,把育性的主效QTL定位在染色体2A、2B、5D、6B、7B和7D上,分别位于2A的Xgwm1053标记附近、2B的Xgwm148-Xgwm374区间、5D上gdm138标记附近和Cfd266-Xgwm583区间及Cfd3-Xgwm292区间、6BS上Wmc494标记附近、7BS Xgwm111-Xgwm537区间,7DS的Xgwm44-Cfd14区间,贡献率分别为8.80%-18.38%、8.56%-13.71%、7.24%-12.12%、18.63%-31.63%、11.65%-15.49%、12.70%-20.22%、4.59-5.34%。并且QTL间存在广泛的互作效应,而7D上的QTL与其他QTL的互作最为突出。

本研究利用小麦BS20/Fu3的DH群体的289个系,分别于2005-2006和2006-2007两个年度将该群体种植于北京和安徽阜阳,田间调查挑旗期、抽穗期和结实率情况,采用复合区间作图法,对小麦挑旗期、抽穗期和光温敏核雄性不育性进行QTL分析,研究结果表明: (1)挑旗期共有3个主效QTL,分别位于1BL、1DL和6BL,贡献率为3.34%-15.73%;抽穗期共有4个主效QTL,分别位于1BL、1DL、4AL和6BL染色体上,贡献率为4.93%-19.98%。挑旗期与抽穗期共同的QTL位于1BL、1DL和6BL,分别与cfa2129、cfd65和Xgwm58紧密连锁,与cfa2129的遗传距离为3.05-13.05cM,与cfd65的遗传距离为0.05-2.05cM,与Xgwm58的遗传距离为0.06cM。抽穗期位于4AL上的QTL,只在阜阳两年种植的材料中检测到,与最近标记Barc170的遗传距离为1.7cM-6.1cM,可能由于不同生态环境诱导不同基因的表达。挑旗期和抽穗期的QTL基本一致,推测由于基因的多效性或控制不同性状的基因紧密连锁所致,同时从分子水平验证了两个性状的高度相关性。 (2)利用WinQTLCart和QTLNetwork两个软件分析三种算法的结果,把育性的主效QTL定位在染色体2A、2B、5D、6B、7B和7D上,分别位于2A的Xgwm1053标记附近、2B的Xgwm148-Xgwm374区间、5D上gdm138标记附近和Cfd266-Xgwm583区间及Cfd3-Xgwm292区间、6BS上Wmc494标记附近、7BS Xgwm111-Xgwm537区间,7DS的Xgwm44-Cfd14区间,贡献率分别为8.80%-18.38%、8.56%-13.71%、7.24%-12.12%、18.63%-31.63%、11.65%-15.49%、12.70%-20.22%、4.59-5.34%。并且QTL间存在广泛的互作效应,而7D上的QTL与其他QTL的互作最为突出。

根据抑制消减杂交(SSH)片 段设计了两个特异性引物(GSP1和GSP2),并利用UniversalGenomeWalker技术,获得510bp的基因序列。blast比对结果 表明该基因序列与玉米T胞质雄性不育恢复因子基因、反转录转座子反转录酶基因高度同源,可能为温敏核雄性不育相关基因。

根据抑制消减杂交(SSH)片 段设计了两个特异性引物(GSP1和GSP2),并利用UniversalGenomeWalker技术,获得510bp的基因序列。blast比对结果 表明该基因序列与玉米T胞质雄性不育恢复因子基因、反转录转座子反转录酶基因高度同源,可能为温敏核雄性不育相关基因。

S-type cytoplasmic male sterility (CMS-S) in maize is associated with high levels of a 1.6-kb RNA in mitochondria. This RNA contains two chimeric open reading frames (ORFs), orf355 and orf77. The previously described nuclear restorer-of-fertility allele Rf3 causes the processing of all transcripts that contain these chimeric ORFs. The Lancaster Surecrop-derived inbred line A619 carries a restor...

为加快谷子杂种优势利用的研究进展、寻找谷子光敏雄性不育基因,利用SSR方法对谷子光敏雄性不育基因进行了分子标记。首先用166对引物在谷子光敏不育系GM与恢复系恢东1号两亲本间进行了筛选,其中有61对引物在亲本间存在差异;经F2群体153株单株验证后,仅有一对引物b159和目标基因连锁;通过Kosambi函数计算,其连锁距离为13.5 cM,位于第6条染色体。

为加快谷子杂种优势利用的研究进展、寻找谷子光敏雄性不育基因,利用SSR方法对谷子光敏雄性不育基因进行了分子标记。首先用166对引物在谷子光敏不育系GM与恢复系恢东1号两亲本间进行了筛选,其中有61对引物在亲本间存在差异;经F2群体153株单株验证后,仅有一对引物b159和目标基因连锁;通过Kosambi函数计算,其连锁距离为13.5 cM,位于第6条染色体。

温敏雄性不育系具有育种程序简单、组配自由、育种周期短等优点,已成为杂种优势利用的重要材料。本研究以芥菜型(Brassica juncea L.)油菜温敏雄性不育系K121S与核不育系1161A获得的BCF1为作图群体,利用混合分组分析法(bulked-segregant analysis BSA)对温敏雄性不育系K121S的育性转换基因(Fc)进行定位。结果表明获得2个基于RAPD的SCAR标记与育性转换基因(Fc)连锁,即是SS503-250和SBA485-482,与育性转换基因的遗传距离分别为3.94 c M和7.09 c M。本研究结果为今后育性转换基因的克隆、测序及生物信息学研究并解析K121S育性转换的分子机制机制提供了条件。

温敏雄性不育系具有育种程序简单、组配自由、育种周期短等优点,已成为杂种优势利用的重要材料。本研究以芥菜型(Brassica juncea L.)油菜温敏雄性不育系K121S与核不育系1161A获得的BCF1为作图群体,利用混合分组分析法(bulked-segregant analysis BSA)对温敏雄性不育系K121S的育性转换基因(Fc)进行定位。结果表明获得2个基于RAPD的SCAR标记与育性转换基因(Fc)连锁,即是SS503-250和SBA485-482,与育性转换基因的遗传距离分别为3.94 c M和7.09 c M。本研究结果为今后育性转换基因的克隆、测序及生物信息学研究并解析K121S育性转换的分子机制机制提供了条件。

通过对新选育的甘蓝型油菜高温敏感生态型不育系417S与30份中外品种（系）进行测交、杂交和回交,研究其温敏不育性的遗传特点.结果表明：（1）30份品种（系）可不同程度的恢复417S的育性,其中24个品种（系）可完全恢复417S育性,占所配组合的80.0%;5个品种（系）可高度恢复417S的不育性,占所配组合的17.2%.（2）自然条件下同一组合正反交F2群体育性分离结果不同,人工控温条件下不同组合F2分离群体中可育与不育呈现15∶1分离,回交群体中出现3∶1分离,表明417S温敏不育性受细胞质和2对隐性重叠核基因共同控制.（3）以417S与1521C构成的回交一代群体为试材,采用分离群体分组分析法（BSA法）对回交一代群体构成的不育集团和可育集团筛选育性基因的RAPD标记,从247个供试引物中筛选出2个引物BA392（5′-AGTCACTCCC-3′）、S113（5′-GACGCCACAC-3′）在不育群体和可育群体间扩增出多态性产物.经进一步对F2分离群体的单株检测,引物BA392扩增出了得到重复验证和可靠的多态性扩增产物,其产生的特异条带BA392-400bp与417S温敏雄性不育的恢复基因连锁,遗传图距为6.0cM,可作为417S温敏不育恢复基因的连锁标记.

通过对新选育的甘蓝型油菜高温敏感生态型不育系417S与30份中外品种（系）进行测交、杂交和回交,研究其温敏不育性的遗传特点.结果表明：（1）30份品种（系）可不同程度的恢复417S的育性,其中24个品种（系）可完全恢复417S育性,占所配组合的80.0%;5个品种（系）可高度恢复417S的不育性,占所配组合的17.2%.（2）自然条件下同一组合正反交F2群体育性分离结果不同,人工控温条件下不同组合F2分离群体中可育与不育呈现15∶1分离,回交群体中出现3∶1分离,表明417S温敏不育性受细胞质和2对隐性重叠核基因共同控制.（3）以417S与1521C构成的回交一代群体为试材,采用分离群体分组分析法（BSA法）对回交一代群体构成的不育集团和可育集团筛选育性基因的RAPD标记,从247个供试引物中筛选出2个引物BA392（5′-AGTCACTCCC-3′）、S113（5′-GACGCCACAC-3′）在不育群体和可育群体间扩增出多态性产物.经进一步对F2分离群体的单株检测,引物BA392扩增出了得到重复验证和可靠的多态性扩增产物,其产生的特异条带BA392-400bp与417S温敏雄性不育的恢复基因连锁,遗传图距为6.0cM,可作为417S温敏不育恢复基因的连锁标记.

Diploid cotton, due to its inherent problem of stamen brittleness, its found unsuitable for traditional method of hybrid seed production which involves hand emasculation followed by pollination. Due to shortfall in other methods viz., Genetic Male Sterility (GMS), as well as, Cytoplasmic Genetic Male Sterility (CGMS), hybrid seed production in diploid cotton becomes costly and thereby, covers less area among the total cotton grown area. Thermo-sensitive genetic male sterility, which overcomes the drawbacks of both GMS and CGMS can be an effective tool in coming years for hybrid cotton research. Understanding fertility and sterility variations, their relation with biochemical changes in plant is important before its application in plant breeding. Hence, the available TGMS line, Ga TGMS-3 obtained at Cotton Research Centre, UAS, Dharwad was studied for callase activity and markers associated with TGMS. The line Ga TGMS-3 had fertile anthers and showed less callase enzyme activity at pre-meiosis stage, high enzyme activity at tetrad releasing microspore stage and no callase activity during other stages. The counterpart TGMS sterile anthers displayed little higher callase activity at pre-meiosis stage, high activity at tetrad stage, but poor activity at tetrad releasing microspore stage. During tetrad stage, TGMS sterile anthers showed high callase enzyme activity giving every chance for early release of poorly developed microspores as compared to fertile anthers. At tetrad releasing microspores stage during which fertile anthers had strong callase enzyme activity led to microspores being released normally and developed normal pollen grains as compared to sterile anthers. The present investigation revealed that NAU2176, NAU2096 and BNL1227 primers can be used as tightly linked markers for TGMS trait, as evident from their differential expression in fertile and sterile anthers.

The two line method of temperature sensitive genetic male sterility (TGMS) is a useful method for production of hybrid seed in crop plants. TGMS 1-1 line has been identified, characterized and stabilized in desi cotton (Gossypium arboreum L.). It was completely male sterile under high minimum temperature of summer months and exhibited complete pollen fertility under low temperature condition. The Critical Sterility Point was determined as 24°C minimum temperature and 40°C maximum temperature with continuous sunshine and Critical Fertility Point was determined as 18°C minimum and 33°C maximum temperature. The inheritance studies revealed that the trait is governed by single recessive gene. The TGMS 1-1 line developed and characterized was found useful for hybrid seed production in May (100% male sterile) when the minimum temperature was above 24°C and for maintenance when sown in the normal kharif by selfing.

The two-line hybrid system in rice is becoming more important and employs environment-conditioned genic male sterile (EGMS) lines sensitive to photoperiod (photoperiod-sensitive genic male sterile), temperature [temperature genic male sterile (TGMS)], or a combination of the two (photoperiod temperature genic male sterile). At least 18 EGMS genes have been mapped, and two cloned, but controversies exist. For example, three different genes were reported to underlie the TGMS trait in three independently identified progenitors, Annong S-1, Zhu 1S, and Guangzhan 63S, while another study demonstrated that the TGMS genes in Annong S-1 and Zhu 1S are allelic. In the present study, we confirmed the allelism of the three TGMS genes, which means there is a common TGMS gene(s) in these lines. Knowing there is an association between the mutant allele ( RNZ m ) of a ribonuclease gene ( RNZ ) with the TGMS trait in Guangzhuan 63S, we then sequenced RNZ for 14 commercial EGMS and 21 non-EGMS lines, and we developed two derived cleaved amplified polymorphic sequence (dCAPS) markers to detect RNZ m alleles in 32 EGMS and 310 non-EGMS lines. The analyses showed that the RNZ m allele existed exclusively in EGMS lines; all non-EGMS lines contained the functional RNZ gc or RNZ tc allele. Furthermore, two segregating populations that included 2,429 individuals were developed by crossing Zhu 1S ( RNZ m ) to two non-EGMS lines (both with RNZ tc ); examination of the segregation of male sterile and fertile plants indicated that the TGMS trait was under the control of a single gene; analysis of the markers revealed the RNZ m allele exclusively in TGMS plants and the RNZ tc allele only in non-TGMS plants in both populations. The dCAPS markers could therefore help select TGMS progeny in breeding programs, which will save time and labor, and improve breeding efficiency and accuracy.

Genic male sterility conditioned by either photoperiod (PGMS) or temperature (TGMS) is the key trait that has enabled the establishment of the two-line hybrid rice ( Oryza sativ a L.) system. The PGMS trait is known to result from a C→G mutation in a long noncoding RNA gene ( lncR ) and the TGMS from a premature stop codon mutation (TC/GC→TA) in an RNase Z gene ( RNZ ). To develop an efficient genotyping method capable of distinguishing all potential genotypes for the loci of lncR and RNZ , the present study explored the capacity of four approaches in high-resolution melting (HRM) curve analysis, viz. amplicon scanning, amplicon scanning with pre-PCR addition of mutant DNA template or inclusion of an unlabeled oligonucleotide probe, and melting analysis by competitive amplification of differentially melting amplicons (CADMA). The former three approaches were demonstrated to be able to differentiate only a few genotypes; in contrast, CADMA was shown to be able to discriminate all possible genotypes of both genes. For the lncR locus, HRM curves of three possible genotypes (PGMS, wild-type line and their hybrid) had peak fluorescence differences (Δ F s) of ~0.075 to ~0.20, significantly greater than the threshold (>0.05) for differentiation. For the RNZ locus, the five genotypes that would be of interest to breeders and seed technologists were separated according their HRM curves with Δ F s02>02~0.1 between any two genotypes. The usefulness of the CADMA-based approach was further validated by analyzing a number of uncharacterized genotypes including P/TGMS lines, F1 hybrid seeds and F2 plants derived from crosses of P/TGMS lines with wild-type lines. Taken together, the present study proved the usefulness of CADMA in plant genotyping and established a CADMA-based HRM analysis method for high-throughput P/TGMS genotyping, which can be applied not only to marker-assisted selection of PGMS and TGMS rice but also to seed purity testing in the two-line hybrid rice system.

By recombining the photo-sensitive Genic Male Sterile (PGMS) gene from Nongken 58S and the thermo -sensitive Genic Male Sterile (TGMS) genes from AnnongS, it was found that the frequency of PGMS plants was greatly increased, and abundant PGMS plants with various characteristics were obtained in the filial generations, and the male sterility of the rPGMS (recombinogenic PGMS and TGMS genes) plants was complete and stable. The recombination of PGMS and TGMS genes can not only solve the problems of incomplete sterility of PGMS lines, but also provide a very effective way to develop various types of elite rPGMS lines. Bycrossing an rPGMS line with another rPGMS line, more than 70% of F2 plants were found to be photo-sensitive male sterile. Based on the method, several rPGMS lines with low critical sterility-inducing temperature were developed in our study. When an sTGMS line (TGMS line with lowest critical sterility-inducing temperature) was crossed with its near iso-genic line, an rPGMS line, an rPTGMS line (TGMS line with PGMS and TGMS genes) or a TGMS line with high critical sterility-inducing temperature, the F1s saw a lowest critical sterility-inducing temperature and can be used to replace sTGMS lines in hybrid seed production. sTGMS lines were also multiplied by planting in a green house with supplementary pollination.

Rice is one of the most important crops as it supports over 25％ of total caloric intake for humans (Kusano et al.,2015).The world population reached 7.3 billion in 2015 and is projected to reach 8.5 billion in 2030 (Word Population Prospects:2015 Revision).To meet the food demands for the ever-increasing population with limited arable land,scarce natural resources and threat of climate change,the rice yield must be increased by 40％ before 2030 (Khush,2005).Therefore,it's imperative to improve crop yield by utilizing hybrid breeding technologies and new methods,such as molecular marker-assisted breeding and transgenic approaches,as well as rational designs based on the recent knowledge of wide-cross compatibility,inter-subspecific heterosis and identification of genes for major yield and quality traits (Qian et al.,2016).

Abstract Hybrid rice breeding offers an important strategy to improve rice production, in which the cultivation of a male sterile line is the key to the success of cross-breeding. CRISPR/Cas9 systems have been widely used in target-site genome editing, whereas their application for crop genetic improvement has been rarely reported. Here, using the CRISPR/Cas9 system, we induced specific mutations in TMS5, which is the most widely applied thermo-sensitive genic male sterility (TGMS) gene in China, and developed new "transgene clean" TGMS lines. We designed 10 target sites in the coding region of TMS5 for targeted mutagenesis using the CRISPR/Cas9 system and assessed the potential rates of on- and off-target effects. Finally, we established the most efficient construct, the TMS5ab construct, for breeding potentially applicable "transgene clean" TGMS lines. We also discussed factors that affect the editing efficiency according to the characteristics of different target sequences. Notably, using the TMS5ab construct, we developed 11 new "transgene clean" TGMS lines with potential applications in hybrid breeding within only one year in both rice subspecies. The application of our system not only significantly accelerates the breeding of sterile lines but also facilitates the exploitation of heterosis.

Abstract Targeted mutagenesis, editing of endogenous maize (Zea mays) genes, and site-specific insertion of a trait gene using clustered regularly interspaced short palindromic repeats (CRISPR)-associated (Cas)-guide RNA technology are reported in maize. DNA vectors expressing maize codon-optimized Streptococcus pyogenes Cas9 endonuclease and single guide RNAs were cointroduced with or without DNA repair templates into maize immature embryos by biolistic transformation targeting five different genomic regions: upstream of the liguleless1 (LIG1) gene, male fertility genes (Ms26 and Ms45), and acetolactate synthase (ALS) genes (ALS1 and ALS2). Mutations were subsequently identified at all sites targeted, and plants containing biallelic multiplex mutations at LIG1, Ms26, and Ms45 were recovered. Biolistic delivery of guide RNAs (as RNA molecules) directly into immature embryo cells containing preintegrated Cas9 also resulted in targeted mutations. Editing the ALS2 gene using either single-stranded oligonucleotides or double-stranded DNA vectors as repair templates yielded chlorsulfuron-resistant plants. Double-strand breaks generated by RNA-guided Cas9 endonuclease also stimulated insertion of a trait gene at a site near LIG1 by homology-directed repair. Progeny showed expected Mendelian segregation of mutations, edits, and targeted gene insertions. The examples reported in this study demonstrate the utility of Cas9-guide RNA technology as a plant genome editing tool to enhance plant breeding and crop research needed to meet growing agriculture demands of the future.