Identification, validation and candidate gene analysis of major QTL for Supernumerary Spikelets in wheat

Abstract

Abstract The number of spikelets per spike is a key trait that affects The number of spikelets per spike is a key trait that affects grain yield in bread wheat (Triticum aestivum L.) In this study, four recombinant inbred lines (RILs) populations were generated and used, having YuPi branching wheat (YP), with Supernumerary Spikelets (SS) phenotype, as a common parent. QTL (QSS.sicau-2A and QSS.sicau-2D) related to SS trait were mapped on chromosomes 2A and 2D (Chr.2A and Chr.2D) through bulked segregant exome sequencing (BSE-Seq) analysis. 14 molecular markers were further developed within the localization interval, QSS.sicau-2Awas narrowed to 7.3 cM covering 11.3 Mb physical region of the reference genome, explained 6.3%~15.6% the phenotypic variance, and QSS.sicau-2D was narrowed to 0.9 cM covering 6.9 Mb physical region of the reference genome, explained 23.4%~34.8% the phenotypic variance, respectively. These two QTL were validated in three different genetic backgrounds by the linked markers. QSS.sicau-2A was identified as WFZP-A, and QSS.sicau-2D was a novel locus that was different from WFZP-D. TraesCS2D03G0260700 was predicted to be a potential candidate gene for QSS.sicau-2D based on the gene expression patterns, gene annotation and sequence analysis. Overall, This study will be useful for cloningQSS.sicau-2D in wheat.