Heading date of rice is a key agronomic trait determining cultivated areas and seasons and affecting yield. In the present study, ifve primary single segment substitution lines with the same genetic background were used to detect quantitative trait loci （QTLs） for heading date in rice. Two QTLs, qHD3 and qHD6 on the short arm of chromosome 3 and the short arm of chromosome 6, respectively, were identiifed under natural long-day （NLD）. Nineteen secondary single segment substitution lines （SSSLs） and seven double segments pyramiding lines were designed to map the two QTLs and to evaluate their epistatic interaction between them. By overlapping mapping, qHD3 was mapped in a 791-kb interval between SSR markers RM3894 and RM569 and qHD6 in a 1 125-kb interval between RM587 and RM225. Results revealed the existence of epistatic interaction between qHD3 and qHD6 under natural long-day （NLD）. It was also found that qHD3 and qHD6 had signiifcant effects on plant height and yield traits, indicating that both of the QTLs have pleiotropic effects.
LI Guang-xianCHEN Ai-huaLIU XuWANG Wen-yingDING Han-fengLI JunLIU WeiLI Si-shenYAO Fang-yin
以红旗16为受体、明恢63为供体,经杂交和回交得到BC4F1。利用643对SSR分子标记对所构建的抽穗期基因早晚池和亲本进行多态性筛选,得到4对多态性标记。将筛选出的杂合单株进行自交,获得BC4F2,并从中筛选出抽穗期分离较明显的群体进行田间表型调查和基因型检测。发现目标基因与标记PSM391连锁,位于第7染色体长臂末端,命名为Hd7m。在标记PSM391与第7染色体末端之间合成10对新SSR标记,其中多态性标记RM22156与目标基因相距4.1 c M。该结果为Hd7m基因的精细定位、基因克隆和分子标记辅助育种奠定了基础。
