Dissection Of QTLs For Plant Height And Yield Traits On The Short Arm Of Rice Chromosome6

A genomic region on the short am of rice chromosome6was previously found to play a significant role in the genetic control of yield traits in rice. In this study, a residual heterozygous line was selected from a recombinant inbred line (RIL) population of Zhenshan97B/Milyang46and the resultant F2:3population was employed to dressect quantitative trait loci (QTL) conditioning yield traits and plant height.The RIL population was firstly detected with six polymorphic SSR (simple sequence repeat) markers on the short arm of chromosome6and18ones in other regions. A plant carrying a heterozygous segment between SSR markers RM587and RM402in homgenous genetic background was found. Such a plant is known as residual heterozygous line. This plant was assayed with other78polymorphic SSR marker, including28marekrs on the short arm of chromosome6and50markers in other regions. The heterozygous segment spaned7.3Mb from RM587to RM19784on the short arm of chromosome6. Three more heterozygous segments, a1.4-Mb segment on the short arm of chromsome3, a8.4-Mb segment in the peri-centromeric region of chromsome5and a4.4-Mb segment in the peri-centromeric region of chromsome10, was detected, but these regions were shown to have little effect on the genetic variation in Zhenshan97B/Milyang46populations.Using the plant, an F2:3population consisted of195lines was developed, from which a SSR-marker linkage map was constructed. The population was planted in Lingshui, Hainan Province and China National Rice Research Institute, Hangzhou, China, respectively. Seven traits were mearsured, including panicles per plant (NP), number of filled grains per panicle (NFGP), total number of spikelets per panicle (TNSP),1000-grain weight (TGWT), spikelet fertility (SF), grain yield per plant (GYD) and plant height (PH). QTL analysis was performed with the Composite Interval Mapping (CIM) option of Windows QTL Cartographer2.5.Through the analyses of the population and sub-populations, two QTL clusters for PH and yield traits were delimted into two narrowsing regions on the short arm of chromosome6, providing candidates for fine RM587and RM585displayed significant effect on all the traits studied RM587and RM585displayed significant effect on all the traits studied except for NP, and the highest LOD value almost on the same region; similarly, segment flanked by RM549and RM19715displayed significant effect on NFGP, TNSP, SF, TGWT, GYD and PH, the highest LOD value are almost on the same region too.