Genetic mapping and expressivity of a wheat multi-pistil gene in mutant 12TP

We identified a wheat (Triticum aestivum L.) multi-pistil mutant from an F2 breeding population in 2012,named 12TP (three pistils in one floret).Genetic analysis showed that one dominant gene locus controlled the multi-pistil trait.Using homozygous normal and multi-pistil lines (near-isogenic lines;NILs) derived from the original mutant 12TP,a simple sequence repeat (SSR) marker assay located the 12TP locus on chromosome arm 2DL.Four SSR markers were linked to 12TP and their order was Xcfd233→Xcfd62-12TP→Xwmc41→Xcfd168 at 15.85,10.47,2.89,and 10.37 cM,respectively.The average genetic expressivity of the trait ‘three pistils in one floret'was more than 98％ in seven homozygous 12TP lines;however,the average genetic expressivity in heterozygous F1 plants was about 49％.Thus,the 12TP is a semi-dominant gene locus,which differ from all previously reported multi-pistil mutants.Mutant 12TP is a new useful germplasm for study of wheat floral development and for breeding of high yield wheat.