Genetic mapping reveals novel exotic QTL alleles for seminal root architecture in barley advanced backcross double haploid population

Abstract

Seminal roots establish the basis of the shallow and deep root systems which play a fundamental role in plant development and adaptation. In the present study, we utilized an advanced backcross double haploid population of a cross between spring cultivar Scarlett (recurrent) and wild barley ISR42-8 (donor) to evaluate seminal root variation along with major grain traits. The phenotypic data of root and grain traits was subjected to QTL analysis using a genetic map based on 371 markers. This analysis identified 21 QTL for root angle (9) and grain traits (12) covering the whole genome. Among these, at 9 QTL, the preeminence of exotic alleles from ISR42-8 showed favorable increase in traits values. The strongest QTL was detected at marker locus bPb-8558 (7.52 cM) on chromosome 7H where the introgression of an exotic allele resulted in 31.6% increase in root angle and around 47% roots showed angle greater than 45°. Most QTL for root angle and grain traits were localized on different chromosomes showing their independent genetic inheritance except on 7H which was common for root angle and grain width. The favorable exotic alleles detected here, provide an opportunity to alter seminal root architecture of modern varieties.