水稻穗下第1、2节节间角度的QTL定位

QTL Mapping for Internode angle of the uppermost two nodes in rice

水稻茎秆弯折易引起倒伏，而茎秆弯折处多发生在穗下第1、2节之间。以穗下第1、2节节间角度差异明显的JX103和明恢63为亲本，构建了包括217个单株的F：群体，测量各单株穗下第1～2节节间角度，结果呈连续性多峰非正态分布，表明该性状是受多个基因控制的数量性状。利用420对SSR引物和WinQTLcart2．5软件对水稻穗下第1、2节节间角度QTL进行分析，在第3、4,6、7、12条染色体上各检测到1个QTL，对表型变异的贡献率范围为3．37％～19．15％。其中第4染色体上位于RM307和RM3471区间的qIA-4为主效QTL，对表型变异的贡献率为19．15％，与RM307相距6cM，对分子标记辅助育种有较大价值。

A F2 population including 217 individuals derived from a cross JXI03 and Minghui 63 was constructed. JX103 is significantly different from Minghui 63 in the trait of the internode of the uppermost two nodes（IA）. It indicated that IA was a quantitative trait controlled by several genes because of the abnormal continuous variation of the IAs from all the F2 individuals. Analysed the QTLs of IA by using 420 SSR makers and WinQTLcart 2.5 software. A total of 5 QTLs were detected on chromosome 3,4,6,7 and 12, which explained 3.37% to 19.15% of the obsered phenotypic variances. Of them, qlA-4 located between RM307 and RM3471 on chromosome 4, was a major QTL, about 6eM away from RM307, which explained 19.15% of the obsered phenotypic variances. It is certainly helpful for molecular marker-assisted breeding.