The Epistatic Interaction Analysis Of Heading Date QTLs And Mapping Of Heading Date Gene Hd7m In Rice

Heading date is one of the most important agronomic traits of rice adapting to the environment. Interactions between genes involved in rice flowering and the interactions between these genes and the environment complicate the genetic behavior of heading stage.Fine mapping of rice heading date genes and studying the genetic effects in between, then uncovering the genetic basis of complex traits of rice have practical value for rice breeding.In this study, imcomplete diallel cross was carried on between five single segment substitution lines(SSSLs) with the same genetic background, and homozygous lines with both of the two substitution segments(double segments pyramid lines, DSPLs) were obtained. All of the SSSLs and DSPLs were used to study the interaction of QTL about rice heading date. The following conclusions have got out of the analysis of the heading date QTL polymerization. Gene q Hd8 of WY011 have epistatic interaction contrast with q Hd3 of WY006; q Hd3 of WY006 have epistatic interaction contrast with q Hd4 of WY052; genes q Hd6 of WY030, and genes q Hd10 of WY065 make double fragment polymerization system showed very late heading. Using single segment substitution rice materials WY030, q Hd6-1,q Hd6-2 and q Hd6-3 were cloned; using rice single segment substitution materials WY065,q Hd10-1 and q Hd10-2 were cloned.Using Hong Qi 16 as the recurrent parent and Ming Hui 63 as the donor, a BC4F2 segregation population were developed via a cross between the both parents, and backcrossed with Hong Qi 16. BSA(bulked segregation analysis) method was used to analysis the polymorphism between the two parents. The early heading bulk and the late heading bulk, and the parents were assayed with 443 SSR markers, 4 pairs of polymorphic markers were found between two DNA bulks. BC4F2 Segregation populations derived from inbreeding of BC4F1 plants at heading date separation were obvious in field investigation and genotypes detection and were selected as mapped populations. We screened a SSR marker PSM391 that appeared to be linked to target gene, at the end of chromosome 7, named Hd7 m.Based on the targeted interval, 10 pairs of SSR markers were selected from the public SSR markers according to rice physical map, found polymorphic marker RM22156. The genetic distance between the Hd7 m and RM22156 were 4.1 c M. The result established a basic for molecular marker assisted breeding, fine mapping and gene cloning of Hd7 m.