Characterization of Fertility Alteration in 8 Environment-sensitive Genic Male-sterile Lines of indica Rice

Eight indica ( Oryza sativa L.) environment-sensitive genic male-sterile (EGMS) lines, 2-2S, K1405S, F131S, 2136S, Pei-Ai 64S, 1290S, GD-IS and N17S, were sequentially seeded with 10-15 d interval at three sites, Wuhan in 1997, Guiyang in 1997 and Sanya in 1997 and 1998, China. The results of investigations on self-sterilities showed that all of eight EGMS lines had stable sterile periods of longer than 30 d at Wuhan. They can be used for seed production of two-line hybrid rice, but can not reproduce themselves. Their stable sterile periods were shorter than 30 d at Guiyang, they can reproduce themselves and can not be used for hybrid seed production. In Sanya, their stable sterile periods were longer than 150 d, all of eight lines can be used for seed production in summer and autumn and reproduce themselves in winter. The fertility of all eight lines were sensitive to temperature. The sensitive stages, sensitive duration and critical point of temperatures (CPT) of fertility alteration in various lines were different. The sensitive stages of 2-2S and K1405S were from 18 d to 9 d before heading, the sensitive durations were 7-10 d and the CPTs were 23.7-24.5 degreesC. The sensitive stage, sensitive duration and CPT of F131S were from 17 to 5 d before heading, 13 d and 24.3-24.7 degreesC, respectively. The sensitive stage, sensitive duration and CPT of 2136S were from 18 to 12 d before heading, 7 d and 24.6-25.1 degreesC:, respectively. The sensitive stages, sensitive durations of Pei-Ai 64S, 1290S, N17S and GD-1S were from 24 to 13 d before heading and 10-13 d. And their CPTs were 24.6-25.1 degreesC, 25.5-26.2 degreesC, 25.4-26.1 degreesC,, and 24.1-24.7 degreesC, respectively.

Development of Maweizhan cytoplasmic male-sterile line in rice(Oryza sativa L.)

A male sterile mutant plant was found from the rice field of the local rice variety which was cultivated for a long time in the west of Hubei Province. The plant has more vigorous tillering ability. Its plant height of 95 cm was a bit shorter than that of the normal ones. The plant type, the leaf shape and the color of leaf sheath and glume tip of this mutant were identieal to that of the normal plant whereas the color of arrowhead-shape anther was milky white. This mutant set no seed during self-pollination. When it was crossed with IR24. IR26, Minhui 63 or Xieqing-zaoxuian. the Ffertilities were normal. The fertility of this mutant could be restored by IR24, IR26 and Minhui 63 and maintained by Xieqing-zaoxian. Maxie A was developed in 1987 by the successive backcrossing of the mutant with Xieqing-zaoxian. The percentage of abortive pollen in Maxie A in uninucleate microspore to early binucleate microspore stage is

Effect of day length and temperature on the pollen fertility in photo(thermo)-sensitive genic male-sterile rice

The effect of day length and temperature on the pollen fertility of five photoperiod-sensitive genic male-sterile japonica rice lines (PGMSR) and three temperature-sensitive genic malesterile indica rice lines (TGMSR) were investigated in phytotron. The light source used for illumination was xenon lamp, and the light intensity which plant accepted on the leaf surface was 300—350μmol photons ms. The results indicated that pollens of PGMSR 7001S and E47S aborted completely whereas a little part of 31116S pollens appeared normal under long day photoperiod (LD,25℃,15h) (Table 1). High temperature (HT, 30℃, 12h) and lower temperature (LT,

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.

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.

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.

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.

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.

Studies on GA_3 Spraying Dosage for eui TGMS Rice Changxuan 3S in Its Hybrid Seed Production

[Objective] Changxuan 3S was thermo-sensitive genicmale sterile（TGMS）rice selected from irradiated seeds of Peiai 64S by 350 Gy^（60）Coγ-ray.The aim of the study was to confirm GA3 spraying dosage of Changxuan 3S with eui gene in its hybrid seed production.[Method] Changxuan 3S possessing eui gene and its parent Peiai 64S were chosen as materials.Comparison studies on sensitivity to GA3 in their hybrid seed production were carried out.[Result] The suitable stage for spraying GA3 in the hybrid seed production of Changxuan 3S was at 10% of panicles headed;The optimal dosage was 90 g/hm2 with 2 split sprayings,the first spraying of 45 g/hm2 at heading of 10% panicles and the second one of 45 g/hm2 on the following day.Under the condition of spraying GA3 at the rate of 90 g/hm2,the panicle neck exsertions of Changxuan 3S was ＋1.78 cm,and exserted stigma rate and seed setting rate of Changxuan 3S were 96.87% and 36.44%,being 21.46% and 16.33% more than those of Peiai 64S,respectively.The theoretical yield of ＂Changxuan 3S/9311＂ reached 2 931.90 kg/hm2,which was increased by 1 259.40 kg/hm2 comparing with ＂Peiai 64S/9311＂.[Conclusion] Compared with Peiai 64S,Changxuan 3S is more sensitive to GA3,which results in no or little using GA3 in seed production of Changxuan 3S.Moreover,Changxuan 3S showed higher yield potential than Peiai 64S.

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。

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.

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。

籼型水稻温敏核不育系虬S的选育

虬S是福建省农业科学院水稻研究所以P88S为母本与常规稻广东三抗为父本杂交,通过福建沙县与海南三亚两地穿梭,经6 a 12代的定向培育成的籼型水稻温敏核不育系,具有米质优、外露率高、抗稻瘟、繁制种产量高等特点,2020年通过福建省农作物品种审定委员会审定。

优质光温敏两系不育系邦S的选育与应用

[目的]开展异交特性好、综合性状优良的光温敏两系不育系选育,以培育高产优质两系杂交稻。[方法]采用光温敏两系不育种质华6S为母本和三系保持系种质9946B杂交,经4年7代的系谱法选育,育成了植株矮壮、株型紧凑、株叶形态好、熟期适中、米质优、抗性好的感温型两系不育系邦S,并分析了主要特征特性及其配合力。[结果]光温敏两系不育系邦S不育性稳定,临界温度<23℃;籽粒细长,谷粒长11.2 mm,长宽比达4.0;异交特性好,总外露率平均62.8%,其中双边外露率48.7%。邦S配合力好,先后配组出邦两优908、邦两优香占等7个高产、优质的两系杂交稻组合,并通过国家级或省级审定。[结论]光温敏两系不育系邦S不育性稳定,农艺性状优良,稻米品质优,繁殖系数高,杂种一代优势强,应用前景广泛。