Identification of qRL7, a major quantitative trait locus associated with rice root length in hydroponic conditions

摘要

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 215recombinant 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 BC_3F_3 recombinant lines mapped the QTL to between markers InDell 1 and InDell7,which delimit a 657.35 kb interval in the reference cultivar Nipponbare. To determine the genotype classes for the target QTL in these BC_3F_3 recombinants, the root lengths of their BC_3F_4 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.