| The heterosis between indica and japonica could be20%higher than that of intra-subspecies. However, F1hybrid sterility between indica and japonica is a major factor preventing application of heterosis in indica-japonica hybrids in rice production. This S5n has been incorporated into indica or japonica variety to overcome sterility problem in wide crosses and hybrid rice breeding. However, in the analyses of many indica-japonica hybrids, it has also been observed that there is considerable variation in the fertility level in hybrids from the same WCV crossed to different indica or japonica varieties. Thus, hybrid sterility in different varietal combinations may be explained by allelic interaction at different loci.Partial abortion of female gametes and the resulting semi-sterility of indica x japonica inter-subspecific rice hybrids have been ascribed to an allelic interaction, which can be avoided by the use of wide compatibility varieties. Spikelet semi-sterility was observed in hybrid between Asominori and CSSL34, a chromosome5segment substitution line in which various chromosomal segments from the indica variety IR24have been introduced into a common genetic background of japonica variety Asominori. By constructing the haplotype between molecular markers RM5796and RM163, two loci were found to cause the hybrid sterility via female gamete abortion. Of the two loci, the locus between InDel229and InDel193was identified to S31(t) by its chromosomal location, and the other locus between RMz184and RM17831was different from all the previously reported hybrid sterility loci, and was thereby delimited to a166-kb region on rice chromsome5. This fragment contains sixteen predicted open reading frames.In order to get the Indica male sterile line with high qulity, A cross was made between Zhenshan97B with high amylose content(AC) and Gui9B with intermediate AC. The plants with elite agronomic traits from F4were test crossed to Jin23A and successively backcrossed as recurrent parent, while a CAPS(cleaved aplified polymorphic sequence) molecular marker assistant selection were conduted in BC1F1and BC5F1to determine whether the plant has TT site in Wx genotype. A male sterile line with intermediate AC, H22A, was technically terrified in Guizhou Province in2008.The characteristics of H22A, a new CMS line in seed production were studied,based on the experiment of H22A and II-32A at different sowing date and investigation of the two CMS lines’flowering habits and sensitivity to gibberell. The results showed that the day from sowing to heading of H22A was about105d, more4d than that of Ⅱ-32A, an elite sterile line. Total number of main stem leaf was as much as the CK. Plant height of H22A was about78cm, more16.4cm than that of Ⅱ-32A, total number of spikelet per panicle was about185.5, and its’sensitivity to gibberellin920was stronger than Ⅱ-32A.flowering habits were better than the CK.But the stigma exsertion rate of H22A were slightly lower than Ⅱ-32A.71recombinant inbred lines derived by single seed descended from Asominori/IR24RIL population which given by Kyushu University of Japan were used to analyzing quantitative trait locus(QTL) controlling the chalkiness characters such as chalkiness rate and size in two ceo-enrionment of different heat condition in Guizhou province. The analysis showed:1.the chalkiness characters of rice, such as chalkiness rate, chalkiness size, were controlled by a plurality of QTL and easily effected by environment.2. the QTLs controlled chalkiness rat and chalkiness size were respectively mapped in the C483-C1121section and C115-C483section of the eighth chromosome. By comparing with other people’s mapping, the result suggested the QTLs controlled chalkiness rate and chalkiness size are highly precisional and very stable, which have better utilization value. |
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