title: Identification of qRL7, a major quantitative trait locus associated with rice root length in hydroponic conditions.
abstract: Root system development is an important target for improving yield in rice. Active roots that can take up nutrients more efficiently are essential for improving grain yield. In this study, we performed quantitative trait locus (QTL) analyses using 215 recombinant inbred lines derived from a cross between Xieqingzao B (XB), a maintainer line with short roots and R9308, a restorer line with long roots. Only a QTLs associated with root length were mapped on chromosomes 7. The QTL, named qRL7, was located between markers RM3859 and RM214 on chromosome 7 and explained 18.14-18.36% of the total phenotypic variance evaluated across two years. Fine mapping of qRL7 using eight BC3F3 recombinant lines mapped the QTL to between markers InDel11 and InDel17, which delimit a 657.35 kb interval in the reference cultivar Nipponbare. To determine the genotype classes for the target QTL in these BC3F3 recombinants, the root lengths of their BC3F4 progeny were investigated, and the result showed that qRL7 plays a crucial role in root length. The results of this study will increase our understanding of the genetic factors controlling root architecture, which will help rice breeders to breed varieties with deep, strong and vigorous root systems.
authors.affiliation: College of Agronomy, Shenyang Agricultural University , 120#, Dongling Road, Shenyang, 110161 , China ; State Key Laboratory for Rice Biology, China National Rice Research Institute , 359#, Tiyuchang Road, Hangzhou 310006 , China.
authors.forename: Huimin
authors.initials: H
authors.lastname: Wang
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Xu
authors.forename: Xiaodeng
authors.initials: X
authors.lastname: Zhan
authors.forename: Rongrong
authors.initials: R
authors.lastname: Zhai
authors.forename: Weiming
authors.initials: W
authors.lastname: Wu
authors.forename: Xihong
authors.initials: X
authors.lastname: Shen
authors.forename: Gaoxing
authors.initials: G
authors.lastname: Dai
authors.forename: Liyong
authors.initials: L
authors.lastname: Cao
authors.forename: Shihua
authors.initials: S
authors.lastname: Cheng
keywords: QTL; hydroponic conditions; qRL7; rice (Oryza sativa L.); root length