Marker-assisted backcrossing for associating nutritional quality to drought tolerance in barley

Abstract

Backcross breeding enhanced by marker assisted selection is currently the most powerful method used to transfer one or a few genes controlling specific traits from one line into another. This method was used to cross naked barley variety, "Tombari" known as A, having high nutritional quality with hulled variety, "Giza131" called B, highly tolerant to drought. The objective of this work is to transfer the hulless variety into the drought tolerant variety. Five generations were realized. In each one, the best performing lines were chosen based on their agronomic, nutritional and molecular features. In the last generation, five remarkable barley lines were selected (H32, H33, H34, H36 and H47). In order to highlight the allele linked to the nudity trait, molecular profile of sKT7 marker, which is tightly linked to the "nud" locus, revealed two specific alleles (I and II). The first one (51 bp) was found in the two parental lines and their progenies. However, the second one (67 bp) was found only in the naked lines (parent A and progenies). This specific allele found only in the naked barley is different from that found by other researchers in Asia and North Europe. This means that naked barley has undergone multiple mutations. Some of the selected lines subjected to physiological stress induced by PEG-6000 showed greater tolerance to stress than their presumed tolerant parents.