Study on Seed Vigor of Rice Photo-ThermoSensitive Genic Male Sterile(PTGMS) Line with Low Temperature Storage

To explore the change rule of seed vigor and seed application technology of rice PTGMS lines with low temperature storage,Zhun S,Y58S,Feng S and Guangzhan 63-4S stored in the seed bank with the temperature of 8-10 ℃ and with the relative humidity of 55% for different years were used as the materials to study the properties of seed vigor,growth and development in the field, etc. The re- sults showed that the germination potential, germination rate, germination index and vigor index of rice PTGMS lines seeds showed downward trends as the time of low temperature storage prolonged,and all of the germination rates of the seeds within five years were over 60%. The conductivity in the soaked solution of seeds was significantly increased with the prolonged low temperature storage time. Seedling rate,root length,white root number,base stem width and seedling dry weight of seeds showed downward trends as the time of low temperature storage prolonged. There was no significant difference between two integral seedling qualities of seeds within 4-6 years in low temperature storage. Compared with the germination rate of low temperature storage seeds soaking for 6,12 and 24 h,the appropriate soak time of long time low temperature storage or low vigor seeds was 12 h. A serious natural aging phenomenon occurred in low temperature storage seeds after out of the storage. The germination rate of seeds placed under natural condition for 50 d decreased obviously. The duration from seeding to heading of Zhun S,Y58S and Feng S shortened as the time of low temperature storage prolonged, while the vari- ation of panicle duration of all PTGMS lines was not obvious. In conclusion, rice PTGMS line seeds with low temperature storage in 5 years could still be used nor- mally. However.seeds after low temperature storage should be sowed as soon as possible, and the soaking time of low vigor seeds should be shortened,and the possibility that the decreased duration from seeding to heading should also be con- sidered.

Characterization of Reverse Thermo-sensitive Genic Male Sterile Lines in Cold Regions of China

Yannong S, a reverse thermo-sensitive genic male sterile （TGMS） line, is sterile at high temperature and fertile at low temperature. In the present study, the fertility of Yannong S and the japonica reverse TGMS lines derived from it was in- vestigated in Harbin, Heilongjiang from 2013 to 2015. The results showed that Yan- nong S was completely male sterile in July and August （the hottest months of the year in Harbin）, and the seed setting rate of bagged panicles was 0. We also in- ferred that the critical temperature for inducing the sterility of Yannong S was higher than 28 ℃. Most of the japonica reverse TGMS lines derived from Yannong S were completely aborted in July and August, with a seed setting rate of 0. It can be con- cluded that the reverse TGMS lines derived from Yannong S are genetically stable lines that have a long period of sterility in cold regions, so they may be the ideal genetic materials for the development and in-situ seed production of japonica hybrid rice.

Preliminary Study on Inheritance of Stigma Exertion in Wheat Thermo-photo Sensitive Genic Male Sterile Line

Stigma exertion is one of the key factors for improving the outcrossing ability of wheat thermo-photo sensitive genic male sterile（TPSGMS） line. A DH population derived from K239S/K92 S was constructed to investigate the inheritance of stigma exertion. K239 S and K92 S are TPSGMS lines with higher and lower stigma exertion rates（SER）, respectively. The SERs of parents, reciprocal crosses and the DH population were evaluated for two consecutive years. The results showed that no significant difference was observed in SER between F1 s of K239S/K92 S and K92S/K239 S,implying that stigma exertion was a trait controlled by nuclear gene（s）. In the DH population, the segregation of low and high SERs fitted to a ratio of 3 ∶1 by Chisquare test, suggesting that the stigma exertion of K239 S was controlled by one pair of recessive genes. In addition, the effects of temperature and humidity on the expression of stigma exertion were also discussed.

Improving Blast Resistance of a Thermo-Sensitive Genic Male Sterile Rice Line GD-8S by Molecular Marker-Assisted Selection

The broad-spectrum blast resistance gene Pi-1, from donor line BL122, was introduced into a thermo-sensitive genic male sterile rice line GD-8S, which possessed good grain quality but high susceptibility to rice blast, by using backcross breeding and molecular marker-assisted selection. Five elite improved male sterile lines, RGD8S-1, RGD8S-2, RGD8S-3, RGD8S-4 and RGD8S-5, were selected based on the results of molecular marker analysis, spikelet sterility, recovery rate of genetic background and agronomic traits. Thirty-three representative blast isolates collected from Guangdong Province, China were used to inoculate the improved lines and the original line GD-8S artificially. The resistance frequencies of the improved lines ranged from 76.47% to 100%, much higher than that of the original line GD-8S （9.09%）. On the agronomic characters, there were no significant differences between the improved lines and GD-8S except for flag leaf length and panicle number per plant. The improved lines could be used for breeding hybrid rice with high blast resistance.

New Temperature Sensitive Genic Male Sterile Lines with Better Outcrossing Ability for Production of Two-Line Hybrid Rice

An investigation was carried out with three newly developed temperature sensitive genic male sterile （TGMS） lines for their floral traits, seed production potential and outcrossing ability in ten cross combinations. In the TGMS lines, fertile pollens had an average diameter of 0.89 mm while the sterile pollens was with 0.02 mm diameter.TS-29-150GY produced the biggest fertile pollens with 0.92 mm and other two lines produced relatively smaller pollens with 0.91 and 0.85 ram. Pollen fertility during the fertility reversion period was an average of 60.7%. TS-29-150GY had the maximum of 66.9% spikelet fertility whereas other two lines （TNAU18S and TNAU60S） had relatively lower spikelet fertility of 27.8% and 26.7%, respectively. Average of 17.00 g of seed yield was obtained in the TGMS lines during the fertility reversion period. TS-29- 150GY had the highest value of 21.20 g of seed yield while TNAU18S and TNAU60S produced 16.6 g and 13.2 g of seed yield, respectively. The low seed production ability of these three TGMS lines was attributed only to the environmental conditions prevailing during the period. All three TGMS lines had considerable outcrossing potential of 41.2%, 24.6% and 25.0%, respectively. The cross combinations viz. TNAU18S/IET21508 （36 g/plant）, TNAU18S/IET21044 （13 g/plant）, TNAU18S/IET21009 （26.5 g/plant）, TNAU60S/CB-09-106 （26.2 g/plant）, TNAU60S/IET21009 （14 g/plant） and TS29-150-GY/DRR 3306 （39.2 g/plant） showed perfect synchronization with acceptable hybrid seed yield, indicating suitability of TGMS system under Indian condition. Based on the outcrossing related traits viz. panicle exertion, angle of glume opening, stigma length and pollen size, TNAU18S was identified as the best, followed by TS-29-150GY.

Inducing fertility restoration in the genic male sterile line of rice with chemical regulators

For the first time, the fertility of rice genic male sterile line was partially restored with the application of chemical regulators at Hainan Rice Breeding Nursery on Mar 1993. A single panicle of the rice plant could bear as many as 27 grains. The chemical agent that could modulate the growth of the rice plants of genic male sterile line was developed by Prof ZHOU Guangqia and his colleagues at the Biology Institute, Hunan Teachers University, China.

Molecular Markers and Agronomic Traits of a New Kind of Genic Male Sterile Material Mian 7AB-4-2 in Brassica napus L.

[ Objective] The study was to investigate the agronomic traits and breeding characteristics of genic male sterile material Mian 7AB-4- 2 in Brassica napus. [ Method] The differences in agronomic traits and polymorphisms in SSR markers, between the genic male sterile material Mian 7AB-4-2 in Brassica napus and its sisterly line Mian 7AB-4-1 were investigated by hybridization and molecular identification; and the percentage of sterile individuals of Mian 7AB-4-2 and of the hybrids with its sisterly line Mian 7AB-4-1 from test cross and back cross were also studled. [ Result] Mian 7AB-4-2 was not significantly different in agronomic traits from its sisterly line Mian 7AB-4-1 at 0.05 probability level. The per- centages of sterile individuals in the pollinated fertile Mian 7AB-4-2 plants were over 60%, and that in its sisterly line Mian 7AB-4-1 was about 25%. In test crosses with other nine sterile lines, Mian 7AB-4-1 kept the percentage of sterile individuals of sterile lines over 90%, and the percentage of sterile individuals from back cross over 80%. With regard to molecular markers, Mian 7AB-4-2 and its sisterly line Mian 7AB-4-1 were different in the band number from SSR primers a2 and E10. [ Conclusion] The results indicate that Mian 7AB-4-2 is helpful for rapeseed breeding, quickening the application of new materials in field breeding.

小麦光温敏核雄性不育系BS366和BS1086杂种一代结实率研究

为了解小麦光温敏核雄性不育系BS366和BS1086的育性恢复状况,评估恢复系人工定向改良对其恢复能力的效果,在不育生态区对以55份定向改良的恢复系和33份非改良恢复系(常规小麦)为父本配制的杂种一代的结实率进行了分析。结果表明,BS366和BS1086杂种一代结实率变化范围为15.42%~140.34%和20.28%~119.07%(国际法),平均结实率分别为73.02%和72.21%,二者差异不显著,说明2份母本的育性恢复能力差异不显著。BS366和BS1086杂种一代结实率主要分布于40%~110%和60%~100%间,BS1086杂种一代结实率分布更为集中。BS366和BS1086与改良父本的杂种一代平均结实率分别为84.45%和78.97%,与非改良父本的杂种一代平均结实率分别为53.97%和60.95%,改良父本的平均恢复力高于非改良父本,表明定向改良有利于提高恢复系的恢复力。BS366和BS1086与相同父本的杂种一代结实率差异在-41.66%~61.93%之间,表明相同父本对不同母本的育性恢复力存在差异。BS366和BS1086与相同改良父本的杂种一代中有61.82%的结实率差异分布于-10%~20%之间,与相同非改良父本的杂种一代中有51.52%的结实率差异在-30%~0%之间,表明同一改良父本对不同母本的育性恢复力差异小于非改良父本。BS366与14份父本、BS1086与7份父本的杂种一代结实率高于对照,其中父本14YH261、14YH551、SD036与2份母本杂种一代的结实率均高于对照,说明具有可用恢复力的父本不仅数量极少,而且对不同母本的恢复力存在较大差异。杂种一代主茎穗的平均结实率极显著大于分蘖穗。因此,建议对不同母本分别开展强恢复力的恢复系筛选,并以中选强恢复系为亲本进行定向改良,有效增加杂种一代结实率达对照水平的组合数量,为获得更多强优势杂交组合奠定基础。

香型温敏核不育系皖香22S的选育研究

皖香22S是安徽省农业科学院水稻研究所以1892S为母本、湖南湘穗种业有限责任公司引进的香型籼稻亲本常香39S为父本进行杂交选育的香型温敏核不育系,2023年8月通过安徽省技术鉴定。皖香22S株高85.0 cm,平均每穗总颖花数193.5粒,千粒重24.0 g,株型紧凑,分蘖力较强,叶片直立内卷,有香味,冷水池育性鉴定在14.5 h、23.5℃、6 d条件下,花粉不育度99.95%,套袋自交结实率0.25%。皖香22S在合肥5月20日播种,播始历期为84 d,比近似品种常香39S短5 d左右,主茎叶龄13.2叶。柱头外露率和异交结实率较高。稻瘟病、稻曲病和白叶枯病抗性较好;米质较优;所配组合杂种优势强,其中皖香22S/银月丝苗在2023年的小区优势鉴定中,较丰两优4号增产9.35%,差异达极显著水平。

Solutions to Insecurity Problems in Seed Production of Two-line Hybrid Rice

The insecure problems of seed production have seriously hampered the healthy and sustainable development of two-line hybrid rice.The safety issues on seed production of two-line hybrid rice and current research situation were pointed out in this paper.The three main reasons for unsafety in seed production of twoline hybrid rice were unsuitable site selection,high critical sterility-inducing temperature and the drift of critical temperature.In this paper,strategies and measures were put forward based on many years of practice.It could minimize the risk in seed production of two-line hybrid rice by selecting dual-purpose genic male sterile line with lower critical sterility-inducing temperature and long lower temperature resistant time.Based on the climate data and climatic demands of the ＂three safe-periods＂ in seed production,a new idea for determining appropriate bases and periods for seed production was proposed by using computer technology,which solved the aimless selection of sites and periods for the seed production of two-line hybrid rice.Besides,we established a system of single plant selection and identification method and original seed propagation with cyclic cold water,which could reduce the generation number of original seed propagation in seed production and avoid the drift of critical sterility-inducing temperature.This paper improved the seed production safety in the three aspects of seed nature,seed source and seed production site.

光/温敏核不育系的不育机理及两系杂交稻的发展与展望

本文回顾了中国两系杂交水稻的发展历史;介绍了两系法中光/温敏型核不育系遗传资源的发现和选育;总结了植物中光温敏型雄性不育的遗传学和细胞学机制;并对水稻两系法中光/温敏型雄性不育系的遗传资源优化及育种策略提出了建议。

优质籼型光温敏核不育系荃时S的选育与应用

介绍了荃时S的选育过程、特征特性、配组应用及繁殖技术要点。荃时S是以银312S为母本,与配合力好的优良恢复系YR0822杂交,采用系谱法选育而成的籼型光温敏核不育系,具有育性转换起点温度较低、不育性稳定、异交率高、抗倒伏、米质优等特点,2021年通过安徽省农作物品种审定委员会组织的专家技术鉴定。该不育系与恢复系银泰香占配制的籼型两系杂交水稻品种时两优泰香具有中抗稻瘟病、米质达部标优1级、丰产等特点,并获得2022年(第四届)安徽省优质稻品种食味品质籼稻金奖,2022年通过国家农作物品种审定委员会审定。

籼型特色水稻两系不育系红17S的选育

红17S是福建省南平市农业科学研究所以广占63S为母本与南平当地优质特色红米美人红杂交,后又与籼型两系不育系K12S复交,经福建建阳及海南三亚等地充分利用自然生态条件,4 a 8代培育成的特色红米温敏核不育系,2022年通过福建省农作物品种审定。总结了红17S的选育过程、配组应用及配套繁殖、制种技术。

Thoughts and Practice on Some Problems about Research and Application of Two-Line Hybrid Rice

The main problems about research and application of two-line hybrid rice were reviewed, including the confusing nomenclature and male sterile lines classification, the unclear characteristics of photoperiod and temperature responses and the unsuitable site selection for male sterile line and hybrid dce seed production. In order to efficiently and accurately use dual-purpose genic male sterile lines, four types, including PTGMS （photo-thermo-sensitive genic male sterile rice）, TGMS （thermo-sensitive genic male sterile rice）, reverse PTGMS and reverse TGMS, were proposed. A new idea for explaining the mechanism of sterility in dual-purpose hybrid rice was proposed. The transition from sterile to fertile was involved in the cooperative regulation of major-effect sterile genes and photoperiod and/or temperature sensitive ones. The minor-effect genes with accumulative effect on sterility were important factors that affected the critical temperature of sterility transfer. In order to make better use of dual-purpose lines, the characterization of responses to photoperiod and temperature of PTGMS should be made and the identification method for the characterization of photoperiod and temperature responses of PTGMS should also be put forward. The optimal ecological site for seed production could be determined according to the historical climate data and the requirements for the meteorological conditions during the different periods of seed production.

Selection of Submergence Tolerant Homozygous Line by STS Marker and Twice Submergence Stress

One sequence tagged site marker Subl-1 and twice submergence stress method were used in selection of submergence tolerant homozygous line from Sub-lBS, a submergence tolerant, bentazon sensitive and photoperiod-sensitive and/or thermo-sensitive genic male sterile line that developed by our laboratory. The results revealed that the original Sub-lBS was heterozygous in SublA-1 locus even though it was identical in almost all of agronomical traits and the segregation of SublA-1 was in accordance with Mendelian law based on chi-square test. And then the original Sub-IBS was divided into two groups： one was ofSublA-1 introgression and the other was not; and the two groups were tested by twice submergence stress method. After the first submergence stress that lasted for 12 d, the average plant heights were significant difference at the 1% level between the two groups. After recovery for 10 d, the second submergence stress sustained for 18 d was carried on; and the group with SublA-1 gene was found apparently tolerant than the other group in submergence tolerance.

Fertility Expression of TGMS-Genes in the Backgrounds of indica CMS-lines,B-lines and R-lines of Hybrid Rice

The generation fertility of 51 F1, 19 F2 and 6 BC1 between 3 thermo-sensitive genic male sterile lines （TGMS-lines） Pei＇ai 64S, 6311S and 360S, and the three lines of hybrid rice including 7 indica cytoplasmic male sterile lines （CMS-lines） and their corresponding maintainer lines （B-lines） and 3 indica restorer lines （R-lines） were investigated to study the expression of TGMS-genes in the backgrounds of the three lines of hybrid rice. Pei＇ai 64S has stronger fertility restoring （Rf） genes for CMS-lines and its TGMS trait is governed by 2 pairs of independent recessive genes; The TGMS trait of 6311S is governed by a single recessive gene with weaker Rf-gene in 6311S and the TGMS trait of 360S is governed by a single recessive gene with no Rf-gene in 360S. The investigation on the fertility of F1 plants between 5 CMS-lines and 4 TGMS generations selected from F2 plants of 4 CMS-lines x 6311S confirmed that the expression of TGMS-gene was controlled by Rf-gene in the genetic background of cytoplasm of CMS-lines, but not affected by Rf-gene in the genetic background of normal fertile cytoplasm. The potential breeding strategies of TGMS-lines with cytoplasm of CMS-lines and CMS-lines with the nucleus of TGMS-genes were discussed.

水稻籼型光温敏核不育系福7112S的选育及应用

籼型光温敏核不育系福7112S是以1892S为母本与优质自育材料R0564杂交,采用系谱法选育而成的。该不育系育性稳定、败育彻底、株型紧凑、抗性较好、米质较优,2019年通过安徽省农作物品种审定委员会组织的技术鉴定。本文介绍了福7112S的选育过程,阐述了其主要的特征特性和育性表现,分析了其配组应用,总结了繁殖制种技术,以期为福7112S的推广与应用提供参考。

节水抗旱稻光温敏雄性核不育系沪旱82S的选育与利用

沪旱82S是上海市农业生物基因中心利用沪旱3S(沪旱1S∕青四矮)和沪旱5S(沪旱1S∕黄华占)杂交,经上海和海南等多年异地交叉筛选,育成的光温敏雄性核不育系。其具有不育性稳定、不育起点温度较低、抗病性好、抗旱性强、稻米品质优(达部标3级)等特性,2018年10月通过了上海市品种审定委员会的田间鉴定。利用该不育系选配的两系节水抗旱稻品种‘旱两优8200’通过2021年国家审定;配组的‘旱两优8208’分别通过广西壮族自治区和江西省审定,2023年通过国家审定。

优质籼型水稻光温敏核不育系‘7-163S’特征特性及其基因型解析

为了制定合理的育种计划,对籼型水稻光温敏核不育系‘7-163S’特征特性及基因型进行解析。以‘7-163S’及其配制组合或品种为试验材料,对主要农艺性状进行分析,使用基因组测序和RiceNavi数据库解析‘7-163S’的基因型。结果表明,‘7-163S’农艺性状优异,可繁性好,育性起点温度低、中抗稻瘟病、抗白叶枯病。已育成4个品种或组合,均表现出生育期适中、优质、丰产性好等特点。基因型分析表明‘7-163S’含有稻瘟病、白叶枯病、褐飞虱等抗性等位基因,以及低垩白、高氮肥利用效率、耐冷等优异等位基因。然而,其缺乏广谱抗稻瘟病基因Pi2、Pi9和Pigm、广谱抗白叶枯病基因Xa23、香味基因fgr及镉低积累基因OsCd1和OsNRAMP5等。将基因型与表型结合,可为基因聚合增强‘7-163S’抗性和新品种选育提供理论支撑。

黄绿叶水稻光温敏核不育系gy157S的开花习性

【目的】探明水稻黄绿叶光温敏核不育系gy157S的开花习性,为特色水稻不育系在新品种选育中的应用提供理论依据。【方法】以目前应用比较广泛的实用性水稻光温敏两系不育系C815S为对照,对比研究水稻黄绿叶光敏温不育系gy157S的花粉败育程度、开花习性、柱头外露率等开花习性。【结果】gy157S单株和单穗的开花持续期分别为15.9 d和10.2 d,在11:00—13:00有明显的开花高峰期,午前花率达60.86%,开颖角度为34.0°,自然条件下柱头外露率为65.0%,与C815S相似。gy157S的花粉不育度为99.97%~100.00%,优于C815S的99.73%~99.98%。【结论】gy157S开花习性良好,在11:00—13:00期间进行赶粉制种效率较高,在水稻两系杂交种生产中具有较大的应用价值。