Construction Of Linkage Genetic Map And QTL Mapping Conferring Pistillate Character In Ricinus Communis L.

In this paper,a genetic linkage map of castor(Ricinus communis L.)was constructed and the QTLs conferring pistillate character was mapped with 2 F2 populations(Pop.1 and Pop.2)derived from the cross combination YC2�YF1.The results are as follows:1.A total of 2,264 SSR markers were developed using software MISA and Primer 3,1,584 pairs of which were used to analysis the polymorphism between parents.218 primer pairs showed polymorphism with a percentage of 13.76%,the size of PCR products ranged approximately from 100~500 bp.2.A genetic map of castor was constructed with software Joinmap 4.0,containing 10 linkage groups,coverring 1789 c M of genome,with an average interval of 9.7 c M between markers.The number of markers each group contained ranged from 6 to 35 and the group length ranged from 56.1 c M to 279.1 c M.The marker density varied from 6.3 c M(LG 2)to 13.0 c M(LG 5).There still were 25 gaps(>20 c M)on the map.3.The QTLs conferring Pistillate character were mapped with software Win QTLCart v2.5 and QTLNetwork 2.0 in two populations.A total of 11 QTLs were detected in Pop.1,which totally explained 74.51% of the phenotypic variation,5 of them had additive and dominant effect,others had only epistatic effect.In the 5 QTLs only with single-locus-effect,PC2-1,PC4-1,PC6-1 were major QTLs,which explained 20.91 %,9.73 %,9.15 % of the phenotypic variation respectively.A total of 3 QTLs were detected in Pop.2,which explained 41.71 % of the phenotypic variation,two of them had additive and dominant effect,the other only had epistatic effect.In the 2 QTLs only with single-locus-effect,PC2-1 was a major QTL,which explained 13.47 % of the phenotypic variation.The QTL PC2-1 was detected simultaneously in both populaions,its genetic effect,action mode and contribution rate were similar or close.The epistatic effect were detected in both populations explained 29.78 % and 26.24 % of the phenotypic variation respectively,which demonstrated that the epistatic effect was one of the important genetic components of the pisitillate character.