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.

Research on Theories and Techniques of Irrigation for Safeguarding Seed Production of Two-Line Hybrid Rice

By inducing frequency, intensity and duration of lower temperature in the middle and last ten-day periods in August in the rice-growing areas of southern China, increasing temperature for safe seed production was defined as 2℃. During the sensitive period of fertility, characters of panicle height and canopy structure of TGMS rice, Pei＇ai64S, were measured. Results showed that temperature changes caused by irrigation in fields were below 40 cm of rice plant, and heating effect was significant at 20 cm when the temperature was increased by 3.1 ℃. For the present study, the following irrigation techniques were put forth： the water depth of 15-20 cm, current water used, irrigating after 17：00 and bailing at 10：00 in sunny or cloudy weather, irrigating on whole day, in shady or rainy weather, increasing inflows and outflows in large fields. In the present experiment, pollen fertility and self-fertilized seed setting rate accepted that the techniques were feasible and effective for against lower temperature and safeguarding seed production of two-line hybrid rice.

Causes of Poor Grain Plumpness of Two-Line Hybrids and Their Relationships to the Contents of Hormones in the Rice Grain

This study was designed to elucidate the grain filling characteristics and the causes of poor grain plumpness of some two-line hybrid rice combinations and their hormonal mechanism. Six varieties, including three two-line hybrid rice combinations, that show differences in seed-setting and grain filling, were used. And the contents of starch, sucrose, zeatin （Z） ＋ zeatin riboside （ZR）, indole-3-acetic acid （IAA）, and abscisic acid （ABA）, the ethylene evolution rate, activities of sucrose synthase （SuSase） and starch synthase （StSase） in grains, the seed-setting and grain filling rate were investigated. The correlations amongst these were analyzed. The results showed that the poor grain filling of two-line hybrids was mainly attributed to the higher unfilled grain rate and the lower filling degree of inferior grains. During the early and mid grain filling periods, the sucrose content in inferior grains was greater than that in superior grains for the combinations with poor grain filling, indicating that the substrate concentration was not the principal factor for their slow grain filling and poor grain plumpness of the inferior grains of two-line hybrids. Z ＋ ZR, IAA, and ABA in superior grains were obviously greater than those in inferior grains at early grain filling stage. The maximum and mean contents of Z ＋ ZR, IAA, and ABA were positively very significantly correlated with the maximum and mean grain-filling rate, filling degree, and grain weight. The evolution rate of ethylene was greater in inferior grains than in superior grains and greater for the combinations with poor grain plumpness than those with good grain plumpness at the early or mid filling stages. The evolution rate of ethylene was negatively and significantly correlated with the grain filling rate, the grain filling degree, and the grain weight. Spraying ethephon （ethylene-releasing agent） at the early grain filling stage increased the evolution rate of ethylene, reduced the ABA content and activities of SuSase and StSase, and decreased the grain filling degree and the grain weight. The results were reversed when cobatous nitrate （an inhibitor of ethylene synthesis） was applied. The results suggested that the hormones and their balance play a role in the regulation of grain filling and enzymatic activities, and the poor grain filling is attributed to the low contents of Z ＋ ZR, IAA, and ABA, and the high evolution rate of ethylene in the inferior grains of some two-line hybrid rice combinations. The results suggested that hormones play important roles in the grain filling of some two-line hybrid rice combinations, and their filling degree can be improved by regulating the hormonal contents.

Breeding and Application Techniques of a New Rice Variety Liliang-you 3822 with High Yield and Disease Resistance

Liliangyou 3822 is a novel indica hybrid rice variety that exhibits disease resistance,high yield,lodging resistance,and late maturity.It employs a self-selected two-line sterile line,Li 38S,and a self-selected restorer line,R22.This variety was subjected to a regional test of indica late-maturing groups in the middle and lower reaches of the Yangtze River in 2020.The results demonstrated that the average yield of the variety was 9.95 t/hm 2,which was 10.67%higher than that of the control Fengliangyou 4,indicating a highly significant yield increase.In the continuous test in 2021,the average yield was 9.74 t/hm 2,representing a 6.52%increase over the control,which also exhibited a significant increase.Finally,the average yield of the two years regional test was 9.84 t/hm 2,which was 8.58%higher than that of the control.In the 2021 production test,the average yield of the variety was 9.32 t/hm 2,which was 12.19%higher than that of the control,indicating a remarkably significant yield increase.In 2022,the variety was validated by the National Crop Variety Approval Committee(GSD 20220143).

Breeding of a Water-saving Drought-resistant Two-line Hybrid Rice Variety Wanliangyou 1008

Drought is one of the important factors limiting rice production,and the application of new water-saving rice varieties is urgently needed in rice production.Wanliangyou 1008 bred by Institute of Rice Research,Anhui Academy of Agricultural Sciences is a new two line hybrid rice variety with some good traits,including high drought resistance,high yield and good disease resistance.Wanlingyou 1008 was obtained by crossing drought-resistant high-quality restorer line DJ1008 and disease-resistant two-line sterile line Wan 25S.In this paper,the breeding process,characteristics and seed production technology of the variety were described in detail.

水稻OsCYP22互作蛋白的筛选及验证

为了探究水稻亲环素家族基因OsCYP22的功能,构建OsCYP22酵母双杂交诱饵载体,并利用水稻酵母双杂交cDNA文库筛选与OsCYP22相互作用蛋白。自激活试验结果表明,OsCYP22诱饵载体无自激活活性,也对酵母细胞无毒性。通过对酵母双杂交文库的筛选,共得到38个阳性菌落,结合测序结果和生物信息学的方法筛选到20个可能与OsCYP22相互作用的蛋白。进一步对OsCYP22分别与调控植物根系生长相关基因OsCSN5和OsRUB1的全长互作验证,结果显示OsCSN5与OsCYP22在酵母中相互作用。这为深入研究OsCYP22的生物学功能提供了理论依据。

Practice and Thought on Developing Hybrid Rice for Super High Yield by Exploiting Inter-subspecific Heterosis

Since the breakthrough of grain yield owing to the development of dwarf rice and three-line system hybrid rice, rice breeding for high yield hardly had showed significant progress in the next successive two decades. It was considered that utilizing heterosis between subspecific varieties (Oryza sativa L.) would be an effective approach to increase yield further. During 1987-1993, an indica-japonica hybrid Yayou 2 yielded as high as 10.5 t/ha; however, it failed to be commercialized because of seed purity problem due to non-uniform emasculation by chemical agent in seed production, and sensitivity of seed setting in Ft plants to environmental conditions. In the past decade, two inter-subspeific hybrids, Liangyoupeijiu (Peiai 64S/9311, javanica/indica) and Liangyou E32 (Peiai 64S/E32, javanica/ laponica); both of them exhibited grain yield higher than 10.5 t/ha, and were widely judged as the pioneers of super hybrid rice. Liangyoupeijiu has been successfully popularized over 4 million hectare in wide climatic areas, while Liangyou E32 made a yield record and offered a model of plant ideotype for super hybrid rice. It was considered that in combination with plant ideotype, active physiological functions, and wide-range adaptability to ecological conditions, exploitation of indica-japonica heterosis would be the key approach for super hybrid rice breeding.

Improving the resistance of the rice PTGMS line Feng39S by pyramiding blast,bacterial blight,and brown planthopper resistance genes

Knowledge of rice(Oryza sativa L.)genes and various DNA markers can be used in genomic breeding programs aimed at developing improved elite rice cultivars.We used an efficient genomic breeding approach to pyramid four resistance genes(Pi2,Xa23,Bph14,and Bph15)in the popular photoperiod-and thermosensitive genic male sterile(PTGMS)rice line Feng39S.We performed foreground selection for the target genes,followed by recombinant selection and background selection.This process reduced the sizes of the genomic segments harboring the target genes(566.8 kb for Pi2,1143.9 kb for Xa23,774.7 kb for Bph14,and 1574.9 kb for Bph15)and accelerated the recovery of the recurrent parent genome to proportions ranging from 98.77%to 99.16%,thus resulting in four near-isogenic lines.To assemble the four resistance genes in Feng39S,we performed a double-way cross combined with foreground and background selection to generate two improved lines of Feng39S(Pi2+Xa23+Bph14+Bph15)with a recurrent parent genome recovery of 98.98%.The two lines showed agronomic performance,grain quality,and fertility–sterility transition characteristics similar to those of the original Feng39S line.The newly developed PTGMS lines and corresponding hybrid combinations were resistant to various field blast isolates and seven representative isolates of bacterial blight.At the seedling stage,the lines also showed resistance against brown planthopper.This study provides an efficient and accurate genomic breeding approach for introducing desirable traits into PTGMS lines.

Status and Prospects of Hybrid Rice Breeding in Jiangsu, China

Research on hybrid rice in Jiangsu Province, China began in 1970. Great progress has been made since then, which can be divided into three stages according to the development of hybrid rice breeding and production in Jiangsu Province. The first stage was beginning stage from 1970 to 1980, when progress was mainly made in cytoplasmic male sterile line breeding. The second stage could be described as developing stage, from 1980 to 1995, when indica hybrid rice was rapidly popularized, and japonica hybrid rice became popular later. From 1996, hybrid rice breeding in Jiangsu Province entered the third stage, when both indica and japonica hybrid rice breeding in the three-line system or intersubspecific hybrid rice breeding in the two-line system made a great breakthrough with the successful breeding of the hybrids Feyou 559, 9 You 138 and Liangyoupeijiu. The developing trend of hybrid rice breeding in Jiangsu Province is also discussed.

浏阳市优质杂交水稻新品种比较试验

为筛选出高产、优质、适合浏阳稻作区种植的水稻新品种,加快地域性优质稻的推广步伐。对2022年引进的5个水稻新组合进行品种比较试验,鉴定各品种的丰产性、抗逆性及适应条件。结果表明,参试品种中野香优莉丝、悦两优2646全生育期为133 d,乾两优馥香占全生育期为132 d,冠两优华占全生育期为131 d,云两优2118全生育期为129 d;所有参试品种叶姿直立或挺直,没有发生稻叶瘟病、稻穗瘟病和水稻纹枯病等病害;冠两优华占产量居首位,产量达597.83 kg·(666.67 m^(2))^(-1),其次是云两优2118,产量达582.33 kg·(666.67 m ^(2))^(-1)。悦两优2646、乾两优馥香占的产量分别达578.67和576.67 kg·(666.67 m^(2))^(-1),均显著高于对照。野香优莉丝的实际产量为542.83 kg·(666.67 m^(2))^(-1),与对照差异不显著。综上所述,这5个参试品种产量除野香优莉丝外,其余品种较为理想,可在浏阳市沿溪镇推广种植。

两系杂交中稻培两优537制种技术初探

根据两系杂交中稻培两优537双亲的特征特性,结合湖北的气候特点,研究并提出了选好制种基地、确定双亲的最佳抽穗扬花期和播差期、培育多蘖壮秧、设置合理的行比、插足基本苗、加强肥水管理、建立高产群体、搞好花期预测和调控、巧施“920”、提高授粉质量、严把种子质量关等制种技术措施。

再生稻种植产量差形成的研究

为明确安徽省沿江地区再生稻种植产量差形成的原因,筛选出该地区适宜的再生稻种植品种,以9个杂交水稻品种为试材,比较分析了其头季和再生季生育期、再生力、产量及其构成因素等性状。结果表明,在产量构成因素中,造成不同品种头季稻产量差异的主要因素是单位面积上的有效穗数;导致再生季产量差异的主要因素是单位面积上有效穗数和每穗着粒数。准两优608再生季单产5.27 t/hm^2,2季综合产量高达13.59 t/hm^2,可作为该地区再生稻种植的优选品种;皖稻119和新两优6号头季产量高,再生力较强,再生季产量潜力大,可以作为该地区再生稻种植的候选品种。研究表明,生产中可通过增加单位面积上有效穗数,主攻大穗,并在维持较高结实率的基础上提高千粒质量以实现再生季产量增加和获得2季综合高产。

Cd胁迫下杂交水稻对Cd的吸收及其动态变化

镉（Cd）是非必需的有毒元素，是农业环境和农产品的重要污染物，易被水稻吸收并在籽粒中积累。不同水稻品种拥有不同的独特基因，导致水稻籽粒吸收积累Cd的能力存在一定的差异。因此，开展不同水稻品种耐Cd特性及其不同生育期的吸收转运效率研究具有重要意义。本文采用水培试验，研究了两个水稻（Oryza sativa L.）品种：D83A/R527（低吸收累积Cd）和辐优838（高吸收累积Cd）在不同质量浓度Cd胁迫下籽粒Cd质量分数及不同生育时期水稻根、茎、叶内Cd的吸收积累量及其动态变化特点。结果表明，两种水稻品种在Cd胁迫下籽粒Cd积累量差异显著，辐优838在1.0 mg·L^-1 Cd质量浓度胁迫下籽粒Cd质量分数就已超过国家食品卫生标准；在1.0~3.0 mg·L^-1 Cd质量浓度胁迫下，D83A/R527籽粒内Cd质量分数仅为辐优838的50~60%。随着Cd处理浓度增加和生育时期推进，两种水稻各部位Cd吸收量均表现为逐渐增加，其增加幅度总体表现为：辐优838〉D83A/R527；不同部位中，根的积累效应最强，叶片吸收积累能力最低，辐优838茎、叶吸收积累效率分别是D83A/R527的1.5~2.0倍左右。在1.0~3.0mg·L^-1 Cd胁迫下，水稻Cd积累差异较为显著的时期为灌浆期，辐优838的根系向茎、叶的转移效率大于D83A/R527，且D83A/R527主要表现为由根系向茎Cd转移效率较高，叶片Cd积累相对较少。灌浆期是水稻籽粒干物质积累的重要时期，也是吸收累积Cd的重要时期，这为筛选低吸收积累水稻品种和调控Cd在水稻籽粒中的吸收累积奠定了重要理论基础。

杂交晚稻金优12高产优质制种技术

阐述了三系杂交晚稻金优12在湖北黄冈制种的适宜播期、播差期、插植方式和采用高产优质低耗技术管理肥水、科学喷施"920"、人工辅助授粉、及时防治病虫害、严格去杂保纯、适时收割措施对提高制种产量和质量的作用。

应用低能离子束将抗菌肽ShivaA基因导入恢复系明恢63的研究(简报)

利用低能离子束介导转基因法于 1993年首次获得成功 ,本研究通过这一技术将抗菌肽ShivaA基因导入水稻恢复系明恢6 3成熟胚中 ,经过诱导愈伤和绿苗分化 ,并再生植株 ,经PCR检测分析证明外源基因已整合到再生植株基因组中。

优质两系杂交中稻培两优537的选育与应用

培两优537是湖北省农业科学院粮食作物研究所用籼型光(温)敏核不育系培矮64S与自育优质中籼稻鄂中5号配组育成的两系杂交中籼稻新组合。2005～2006年参加湖北省中稻区试,表现米质优、高产稳产性好、适应性较广,具有较好的应用前景,2007年3月通过了湖北省品种审定委员会的审定。介绍了其选育经过、特征特性及栽培制种技术。

FACE对三系杂交籼稻汕优63磷素吸收利用的影响

在水稻品种中,杂交籼稻因其杂种优势强、抗逆性好、穗型大、产量潜力高,在稻作中占有重要的、不可替代的作用。2005、2006年利用我国惟一的农田开放式空气CO2浓度增高(FACE)研究平台,设计施N量为125kg·hm-(2LN)、250kg·hm-2(NN)处理,研究大气CO2浓度比对照高200μmol·mol-1的FACE处理对三系杂交籼稻汕优63不同生育时期磷素含量、磷素吸收、磷素分配和磷素效率的影响。结果表明:(1)FACE处理使汕优63各生育时期稻株含P率极显著提高,使各生育时期P素吸收量极显著增加,生育中期的增幅略小于生育前、后期;(2)FACE处理使汕优63抽穗后P素在茎鞘中的分配比例显著增加,穗中的分配比例显著下降,对抽穗前P素在叶片、茎鞘中的分配比例均无显著影响;(3)FACE处理使汕优63不同生育期P素干物质生产效率极显著下降,使P素子粒生产效率和P素收获指数亦均极显著下降;(4)增施N肥,使汕优63大多数生育时期的植株P素含量和吸P量得到显著或极显著的增加,使大多数生育时期P素干物质生产效率下降,使P素子粒生产效率和收获指数显著下降;(5)CO2×N、CO2×Y对植株含P率、吸P量的影响有互作效应,FACE处理使汕优63稻株含P率、P素吸收量显著提高;使P素干物质生产效率、P素子粒效率显著下降。

不同水稻药剂浸种对杂交水稻种子萌发及幼苗生长的影响

为了研究不同水稻药剂对水稻种子萌发情况及幼苗生长情况中形态指标和生理生化指标的影响。以金优974水稻品种为实验材料,在以清水作为对照组的条件下,配置相同体积的咪酰胺、石灰水、浸种灵和100g·mL-1的赤霉素等溶液下浸泡水稻种子48h,从而测定包括种子发芽势、发芽率和发芽指数,秧苗根长、苗长和鲜重及苗中抗氧化物酶活性和叶绿素质量分数等指标。可以发现赤霉素和咪酰胺都不会影响水稻的发芽势,而浸种灵、石灰水则降低了水稻发芽势;同时,赤霉素可以提高水稻的发芽率和发芽指数,而浸种灵、石灰水、咪酰胺都会降低水稻的发芽率和发芽指数。对苗的根长和苗长有显著促进作用的是赤霉素,咪酰胺对幼苗根长和苗长有抑制作用以及降低了幼苗的鲜重,其它无显著差异。4种浸种剂使水稻幼苗内SOD活性、CAT活性和叶绿素质量分数的含量相比于清水都有所增加,其中以咪酰胺尤为突出。本实验为水稻种子浸种剂的选取提供了一定的理论依据。

杂交早稻新品种夷优186的选育与应用

夷优186系南平市农科所用夷A与南恢186配组育成的三系杂交早稻新品种,具有生育期适中、高产稳产、适应性广、制种产量高等特性,于2013年通过福建省农作物品种审定。介绍了夷优186的选育经过、产量表现、特征特性、主要栽培技术及制种技术要点。

秋水仙素对杂交水稻发芽率及主要农艺性状的影响

用4种不同浓度的秋水仙素及3种不同处理时间处理田两优4号种子进行多倍体诱导。结果表明:秋水仙素对杂交水稻种子的发芽率及胚芽的生长有抑制作用,但有助于稻穗的伸长;植株高度升高;每穗实粒数与总粒数减少;千粒重增加,结实率下降。胚芽的长度随处理时间增加而变短;穗长与处理时间的关系呈现先降低后升高的趋势;穗长随着处理浓度的增加而增大。