Spike Density Quantitative Trait Loci Detection and Analysis in Tetraploid and Hexaploid Wheat Recombinant Inbred Line Populations

https://www.frontiersin.org/articles/10.3389/fpls.2021.796397/full

Frontiers in Plant Science，12:796397，doi: 10.3389/fpls.2021.796397（2022）

Jianing You1†, Hang Liu1†, Surong Wang1, Wei Luo1, Lulu Gou1, Huaping Tang1, Yang Mu1, Mei Deng1,Qiantao Jiang1,Guoyue Chen1,Pengfei Qi1,Yuanying Peng1,Liwei Tang2,Ahsan Habib3,Yuming Wei1,Youliang Zheng1,Xiujin Lan1*andJian Ma1*

Abstract

Spike density (SD) is an agronomically important character in wheat. In addition, an optimized spike structure is a key basis for high yields. Identification of quantitative trait loci (QTL) for SD has provided a genetic basis for constructing ideal spike morphologies in wheat. In this study, two recombinant inbred line (RIL) populations (tetraploid RIL AM and hexaploid RIL 20828/SY95-71 (2SY)) previously genotyped using the wheat55K SNP array were used to identify SD QTL. A total of 18 QTL were detected, and three were major and one was stably expressed (QSd.sau-2SY-7A.2, QSd.sau-AM-5A.2,QSd.sau-AM-7B, andQSd.sau-2SY-2D). They can explain up to 23.14, 19.97, 12.00, and 9.44% of phenotypic variation, respectively. QTL × environment and epistatic interactions for SD were further analyzed. In addition, pyramiding analysis further revealed that there were additive effects betweenQSd.sau-2SY-2DandQSd.sau-2SY-7A.2in 2SY, andQSd.sau-AM-5A.2andQSd.sau-AM-7Bin AM. Pearson’s correlation between SD and other agronomic traits, and effects of major or stable QTL on yield related traits indicated SD significantly impacted spike length (SL), spikelet number per spike (SNS) and kernel length (KL). Several genes related to spike development within the physical intervals of major or stable QTL were predicted and discussed. Collectively, our research identified QTL with potential applications for modern wheat breeding and broadening the genetic basis of SD.