The Study Of Heterotic Loci Affecting Yield-related Traits Of Indica×Japonica Hybrid Based On The Introgression Lines Population

Changhui T025 is an excellent indica restorer line, and is also the male parent of the super rice variety Wufengyou T025. Habataki is a good indica rice variety introduced from Japan. The performance of F1 between Changhui T025 and Habataki is obvious heterosis.To detect the heterotic loci for the F1 between Habataki and Changhui T025, an introgression lines heterozygotes(ILHs) population was constructed by crossing Changhui T025 with the introgression lines(ILs) carrying indica “Habataki” segments in japonica“Sasanishiki” background, quantitative trait loci(QTLs) analysis was conducted by ILs and ILHs under two different environments(Sanya and Nanchang), the results are as follows:1、A total of 54 QTL affecting yield related traits were detected in the ILs population,and the QTL showed a clustered distribution phenomenon. Among these QTL, only 16 QTL were repeatedly detected in two different environments. The number of QTL where the presence of the Habataki alleles increasing the yield related traits performance was 38,accounting for 70.37% of the total QTL. By comparion, 14 QTL identified in this study showed the same location with the QTL detected by other studies using the same material,the other 40 QTL have not been previously identified.2、23 heterotic loci were identified for yield related traits in the ILHs population, and also showed a clustered distribution phenomenon. The number of heterotic loci contributed higher yield related traits was 17, accounting for 73.91% of the total QTL, where the presence of indica(Habataki)×indica(Changhui T025) hybrid segments increased F1(Sasanishiki×Changhui T025) phenotypic value. There were five QTL(qHgwp4,qHtgw4-1, qHppp10, qHph1-1 and qHdsp1) repeatedly detected in two different environments. Among them, qHgwp4, qHtgw4-1 qHppp10 and qHdsp1 showed positive effect in enhancing the phenotypic value of indica×japonica subspecies hybrid of grains weight per plant, thousand-grain werght, panicles per palnt, density of spikelets per panicle,respectively; The qHph1-1 showed negative additive effects which could significantly reduced the plant height of rice. In addition, qHssr5 and qHssr9 could improve the fertility of indica×japonica subspecies hybrid.3、By comparing the QTL detected by ILs and ILHs population, we found that qSPP1,qDSP1, qPH1-1, qPH1-2 and qDSP4 affecting the spikelets per panicle, density of spikelets per panicle and plant height in ILs population, were also deteted in the ILHs population, which were donated as qHspp1, qHdsp1, qHph1-1, qHph1-2 and qHdsp4, they near RM6887, RM7124, RM7600 and RM5586 on chromosome 1 and 4, respectively. The results showed that these loci might may important gene(QTL) that affect yield related traits and heterosis. Among of them, qDSP1 and qPH1-1(corresponded heterotic loci toqHdsp1 and qHph1-1) were repeatedly detected in both two defferent environment.4、Through the analyses of the quantitative trait loci detected by ILs and heterotic loci detected by ILHs, we found that the IL lines harboring the same yield related traits QTL always showed significant difference phenotypic value for the same trait, which indicated that the QTL could be affected by the size of the introgression segment.