摘要
利用水稻籼粳亚种间组合Asominori×IR24重组自交系(RIL)群体71个株系和相应的全基因组染色体片段置换系(Chromosome segment substitution line,CSSL)群体65个株系,在2种环境下对分蘖角度性状进行了数量性状基因座(QTL)定位和上位性效应的遗传分析.在两种群体中都出现了分蘖角度的超亲分离.在RIL群体中发现了5个主效QTLs和3对上位性双位点互作标记基因座,控制水稻分蘖角度.其中在第9染色体上位于XNpb108～C506 RFLP分子标记区间的qTA-9基因座在2种环境中同时出现,其贡献率平均为28.6%,增加分蘖角度的等位基因来自籼稻品种IR24.利用CSSL群体图示基因型分析,证实在第9染色体上含有RFLP标记C609和C506约15 cM的染色体区段,存在增加分蘖角度的基因,来源于染色体片段供体亲本IR24,在Asominori的遗传背景中能增加分蘖角度约15°,该基因的位置与RIL群体在第9染色体上定位的QTL相同,证实了qTA-9的存在.F1表型测定及F2代遗传分析表明,来自IR24的等位基因是一个不完全显性基因.除一对上位性位点存在显著的环境互作效应外,未发现其他位点存在与环境的互作效应.不同基因的加性效应和双位点的上位性效应的共同作用可能是造成水稻分蘖角度超亲分离的主要原因.
Tiller angle is one of the most important morphological characters that has a significant effect on the formation of rice high-yield population. The tiller angles were measured in a japonica/indica RIL population with 71 lines and a genome-wide chromosome segment substitution line （CSSL） population with 65 lines at two experimental sites. A transgressive segregation was observed in both populations. QTL analysis of tiller angle was conducted based on the saturated RFLP marker linkage map and the CSSL graphical genetype. Five main-effect QTLs and three pairs of epstatic loci were detected in the RIL population. A main QTL, qTA-9,located on chromosome 9 at XNpb108 -C506 ,was identified at both experiment sites. The positive allele TA-9^1 on qTA-9 was contributed by indica rice IR24 with 28.6% average contribution to variance. Meanwhile, an analysis of CSSL graphical genetypes also showed that there was a positive allele on the IR24 chromosome substitution segment delimited by RFLP marker C609 and C506 with approximate 15 cM interval,which proved the existence of qTA-9. The TA-9^1 could increase tiller angle by about 15~ in japonica Asominori background under the two environ- ments. The measurement of the F1 from the cross between background parent and CSSL AIS68 with TA-9^1 and the analysis of F2 population indicated that the TA-9^1 was an incomplete dominant gene. Genetype × environment interaction（ G × E） was not widely present except a pair of epistatic loci with 5.32% contribution to variance of tiller angles and a relatively small additive effect. The combining action of the additive effect of the genes from both parents and the two-loci epistasis-effect may be responsible for the transgressive segregation of tiller angle in rice population. The value and approach of application of TA-9^1 in hybrid rice breeding program were discussed.
基金
国家"863"计划(编号:2003AA207020
2001AA241024)
江苏省自然科学基金(编号:BK2003076)资助~~
关键词
水稻
分蘖角度
染色体片段置换系
数量性状位点
上位性
rice
tiller angle
chromosome segment substitution line （CSSL）
quantitative trait locus （QTL）
epistasis
