籼型巨胚稻的发现及其遗传育种研究

以若干籼稻品种为材料 ,通过核辐射诱变于M3代获得巨胚品系。对巨胚性状作了遗传育种分析。结果表明 ,巨胚属隐性单基因遗传 ,种胚的大小直接由合子基因型决定 ,而与为胚发育提供营养的母株基因型、胚乳基因型及细胞质均无关系。因此 ,可在诱变的M2 世代或杂交F2 世代的种子上直接进行巨胚性状选择。巨胚稻糙米胚重比原来品种大 1倍左右 ,但千粒重与单株产量略有下降。本文还就巨胚稻的育种技术作了讨论。

籼型三系杂交水稻不育系主要农艺性状配合力及遗传力分析

8个不育系和4个恢复系,采用不完全双列杂交试验设计(NCII设计),对8个农艺性状进行配合力、遗传力分析。结果表明,不同性状在两生态区的表现基本一致,大多数性状的一般配合力和特殊配合力方差均达显著或极显著水平,在株高、播始历期、收获指数、千粒重、结实率和穗实粒数上,加性效应起到主要作用,而单穗重和小区产量在两生态区的表现不一致,单穗重在南充点以加性效应为主,在温江点为加性效应和非加性效应共同作用,小区产量在南充点以非加性效应为主,在温江点却以加性效应为主。除单穗重外,其余性状在两生态区均以母本的贡献较大;南充点单穗重以父本的作用较大,温江点父母本的作用基本相当。各性状在两试验点的广义遗传力均较高,在南充点狭义遗传力除小区产量较低外,其余均较高,在温江点,狭义遗传力以结实率、千粒重、收获指数、播始历期和株高较高,而小区产量、穗实粒数和单穗重中等。

贵州省籼型杂稻区试组合在毕节的耐冷性鉴定

为全面充分认识参加贵州省杂交水稻区域试验新组合的耐冷特性和生态适应性,以2010年度参加贵州省杂交水稻区域试验6个组别共69个籼型杂稻组合为耐冷性鉴定材料,在毕节特殊的生态气候条件下,鉴定出耐冷性表现强和较强的组合分别有10个和11个,中等的有10个,较弱的有13个,弱的有25个。

优质籼型不育系T78A的选育及利用

以地谷 B与龙特浦 B和珍汕 97B复交 ,选育出优质、柱头外露率高的株系 ,并与珍汕 97A连续多代成对回交 ,育成不育系 T78A.T78A米质优、不育性稳定、柱头外露率高、异交特性好、配合力强 .用 T78A与早恢 89、福恢 0 16、明恢 82等配制成的杂交早稻组合 T优 7889、 T优 7816、T优 7882等既高产又优质 .其中 T优 7889品质优良、产量高、适应性广 ,已于 2 0 0 1年通过福建省农作物品种审定委员会审定 。

Correlation Analysis of Characters of Indica Hybrid Rice with High Content of Amylose

[Objective] The aim was to research and analyze characters and related correlation of indica hybrid rice containing high amylose. [Method] In the research, major characters of 16 species of groups of {ndica hybrid rice and the correlation were explored in rice belts in Sichuan in 2011. [Result] The variation of chalkiness degree was the highest at 26.8%, followed by rate of head rice at 22.89%; varia- tions of head rice rate and chalkiness degree were lower at 0.72% and 2.61%. In addition, rate of unpolished rice was of significantly negative correlation with chalki- ness degree; rate of chalky rice was of extremely positive correlation with chalkiness degree and gel consistency; chalkiness degree was of significantly positive correla- tion with gel consistency; gel consistency was of significantly negative correlation with protein content; amylose content was of insignificant correlation with gel consis- tency （r=0.166 9） of the 16 hybrid groups. These indicated that gel consistency would be still high as the content of amylose grows （AC≥25%）. For example, when the content of anylose in Chuanxiang 29A/Luhui 37, Kangfeng AJ6684, and Lefeng A/SR536 exceeded 27%, the gel consistency was over 80 mm in the research. [Conclusion] The research provides references for improvement of amylose content in breeding hybrid rice.

Effect of Enhanced UV-B Radiation on Seed Setting Rate and 1 000-grain Weight of Indica Hybrid Rice Restorer Lines

[Objective] This study was to investigate the effect of enhanced UV-B radiation on seed setting rate and 1 000-grain weight of hybrid rice combinations. [Method] The seed setting rate and 1 000-grain weight of 10 new sterile indica restorer lines planted in pots under enhanced UV-B radiation and fluorescent lamps （control） were respectively measured, and the differences were compared. [Result] The enhanced UV-B radiation significantly reduced the seed setting rate of indica restorer lines, and the differences between that UV-B radiation treatment and control all reached extremely significant level. In addition, the enhanced UV-B radiation reduced the 1 000-grain weight of most indica restorer lines, and compared with that of control the difference achieved significant or very significant level. However, the effect of enhanced UV-B radiation on seed setting rate and 1 000-grain weight differed to different indica restorer lines, and the differences among restorer lines tested were significant or very significant, which indicated the possibility to screen antiUV-B radiation rice materials and combinations. Finally, the indica restorer lines 09R-14, Luhui 37 and 10R-7703 which were strongly resistant to UV-B radiation were screened out. [Conclusion] This study laid foundation for breeding hybrid rice varieties resistance to UV-B radiation.

Analysis of Heterosis, Combining Ability and Heritability of Cadmium Content in Brown Rice of Three-line Indica Hybrid Rice

Five cytoplasmic male sterile （CMS） lines were used as parents in an incomplete diallet cross and six restorer lines of rice design （Nc II design）. Thirty hybrid combinations with the same growth period were selected as experimental ma- terials to investigate the heterosis, combined ability and heredity of Cd content in brown rice of indica hybrid rice. According to the results, Cd content in brown rice showed a significantly negative heterosis; the general combining ability and specific combination ability of Cd content in CMS and restorer lines both reached extremely significant level （P〈0.01）, indicating that both genetic improvement of parents and e- valuation of combinations are important to the breeding of hybrid combinations with low accumulation of Cd; the broad-sense heritabitity and narrow-sense heritability of Cd content were both relatively high with slight differences, which respectively reached 97.73% and 80.10%, indicating that Cd content in brown rice mainly de- pends on the additive action of genes; in addition, parent improvement showed bet- ter effect on the selection of early generation.

Comparative Analysis of Main Characters of New Hybrid Rice Combinations with Different Yield Levels

The main characters and yield of 22 new indica hybrid rice combinations were analyzed in order to sort out the common characteristics in the performance of main characters of high-yielding varieties （combinations）.The results showed at the confidence level of 95%, the whole growth pedod ranged from 131.3 to 137.3 d, the effective ear number ranged from 2 495 000 to 3 179 000 ears/hm2, the plant height was in the range of 119.5-131.7 cm, the average ear length ranged from 24.6 to 27.2 cm, the spikelet number per panicle was in the range of 164.2-225.4, the seed setting percentage ranged from 69.4% to 82.3%, and the 1 000-grain weight was in the range of 26.9-31.2 g. The correlation analysis between single traits and yield of rice varieties （combinations） showed that in order to achieve high yield, the medium indica hybrid rice variety with moderate growth period, higher plant height or biological yield, larger panicle and bigger kernel should be selected. In addition, the maximum tiller number should be controlled and adjust- ed, and the spike rate should be improved to ensure sufficient effective ears in the cultivation process.

Isolation and initial characterization of GW5, a major QTL associated with rice grain width and weight

Grain weight is a major determinant of crop grain yield and is controlled by naturally occurring quantitative trait loci （QTLs）. We earlier identified a major QTL that controls rice grain width and weight, GW5, which was mapped to a recombination hotspot on rice chromosome 5. To gain a better understanding of how GW5 controls rice grain width, we conducted fine mapping of this locus and uncovered a 1 212-bp deletion associated with the increased grain width in the rice cultivar Asominori, in comparison with the slender grain rice IR24. In addition, genotyping analyses of 46 rice cultivars revealed that this deletion is highly correlated with the grain-width phenotype, suggesting that the GW5 deletion might have been selected during rice domestication. GW5 encodes a novel nuclear protein of 144 amino acids that is localized to the nucleus. Furthermore, we show that GW5 physically interacts with polyubiquitin in a yeast two-hybrid assay. Together, our results suggest that GW5 represents a major QTL underlying rice width and weight, and that it likely acts in the ubiquitin-proteasome pathway to regulate cell division during seed development. This study provides novel insights into the molecular mechanisms controlling rice grain development and suggests that GW5 could serve as a potential tool for high-yield breeding of crops.

Breeding of New Japonica-indica Hybrid Rice Combination Chunyou 59

Chunyou 59 is a japonica-indica hybrid rice combination developed from Chunjiang 16A(a late japonica CMS line with dwarfness and early anthesis time)and CH59(an indicaclinous wide compatibility restorer line).It has the characteristics of strong heterosis,strong stem,good lodging resistance,large panicles,good cold tolerance,high yield and wide adaptability.It was registered and released by Jiangxi Provincial Crop Variety Appraisal Committee in March 2009.The breeding procedure,characteristics,major techniques of cultivation and seed production of Chunyou 59 were introduced in the paper.

The Restoring Ability of Normal Indica Red Rice Ruby and Its Restoring Gene Mapping

[Objective] This study was to investigate the restoring ability of normal indica red rice Ruby and to carry out its restoring gene mapping. [Method] Normal indica red rice Ruby was hybridized with the sterile lines Zhenxian 97A, D62A, G46A and D702A to prepare their F1, BC1 and F2 progenies, and the pollen fertilities of these progenies were investigated. Meanwhile the restoring genes were mapped using SSLP. [ Result] For the sterile lines tested, Ruby has a gene to restore their fertilities. This gene is located on the chromosome 7 and shows a genetic distance of 7.4 cM with RM182. Unlike the clustering distribution of the restoring genes on chromosome 10, it is a specific restoring gene. [ Conclusion] it is feasible to breed restoring genes controlling red color characters via transgene and backcross.

DNA methylation polymorphism and stability in Chinese indica hybrid rice

Conventional rice breeding has long focused on exploiting the DNA sequence diversity.However,epigenetic diversity,reflected particularly in DNA methylation,can also contribute to phenotypic variation and should not be overlooked in rice breeding.In this study,20 parental lines of indica rice,which are widely used in hybrid rice breeding in China,were analyzed to investigate variations of DNA methylation and its inheritance.The results revealed a wide diversity in DNA methylation among these breeding lines.A positive correlation was seen between DNA methylation and genetic diversity.Furthermore,some of the methylated DNA was inherited in the subsequent generation,regardless of whether they were produced by selfing or hybrid-crossing.This study provides insight into the methylation patterns in rice,and suggests the importance of epigenetic diversity in rice breeding.