直播条件下水稻6个穗部性状的QTL分析

在大田直播条件下,利用来源于＂Lemont/特青＂的重组自交系群体,对水稻6个穗部性状及其相互间遗传相关的分子基础进行了QTL分析,共检测到19个QTL,各性状QTL数为2～4个,单个QTL贡献率为4%～22%。共检测到3个染色体区段能同时影响多个穗部性状,其中第1染色体RM212-RM104和第2染色体RM263-RM221区段的QTL能同时影响单株产量、每穗颖花数、着粒密度和二次枝梗数中的3个或4个性状,且这2个区段的QTL对各性状的效应方向相同,增效等位基因均来自‘特青’,为各性状间表型正相关提供了重要的遗传解释。第11染色体RG1022附近的QTL对着粒密度的效应值为负,来自‘特青’的等位基因增加性状值,而对穗长的效应值为正,来自‘特青’的等位基因降低性状值,为这2个性状间表型负相关也提供了一定的遗传解释。此外,对水稻穗部性状QTL在多种环境和遗传背景下的稳定表达及其在分子标记辅助育种中的应用进行了讨论。

Mapping of QTL Controlling 6 Panicle Traits of Rice under Direct-sowing Environment

To characterize the genetic basis of 6 rice panicle traits as well as their relationships with each other,mapping of quantitative trait locus (QTL) was conducted with a RIL (recombinant inbred line) population derived from a cross between 'Lemont'(japonica var.) and 'Teqing' (indica var.) under a direct-sowing field experiment.A total of 19 QTL were identified,numbers of QTL for each trait varied from 2 to 4,and variations explained by each QTL ranged from 4% to 22%.Three chromosome regions were found to have pleiotropic or linked effects on multiple traits.The two regions RM212-RM104 on chromosome 1 and RM263-RM221 on chromosome 2 showed multiple effects on 3 or 4 traits of grain yield per plant,number of spikelets per panicle,panicle setting density and number of secondary rachis branches in the same direction,and the Teqing genotype increased all the trait values at the two regions,providing a genetic explanation for the positive correlations among the four traits.The other region near RG1022 on chromosome 11 showed multiple effects on panicle setting density and panicle length in the opposite directions,and at this region the 'Teqing' genotype increased the trait value of panicle setting density but decreased the trait value of panicle length,also providing a genetic explanation for the negative correlation between these two traits.In addition,the QTL identified in the present study and previous studies with different mapping populations under vary environments were compared and the application of some stably expressing QTL for high yield breeding programs in rice were discussed.