UTILIZATION OF A RECOMBINANT INBRED POPULATION TO LOCALIZE QTLS FOR ABSCISIC-ACID CONTENT IN LEAVES OF DROUGHT-STRESSED BARLEY (HORDEUM-VULGARE L)

The content of abscisic acid (ABA) in the leaves of drought-stressed plants is a quantitatively-inherited trait. Quantitative trait loci (QTLs) can be mapped using molecular markers and recombinant inbred populations. This approach has been utilized to investigate the genetic control of ABA content in barley (Hordeum vulgare L.). Thirty recombinant inbreds from the Dicktoo x Morex cross, previously characterized by RFLP patterns, were grown in replicated pots and analyzed for ABA content in the leaf under controlled conditions of water deficit. Highly significant differences for ABA content were found among progenies, some of which showed transgressive values over the parental lines. Multiple regression analysis revealed two significant (P<0.001) QTLs on chromosomes 2 and 4, which accounted for 58% of the phenotypic variation among the recombinant inbreds. The QTL on chromosome 4 peaked near the DHN6 locus, which codes for a dehydrin, an ABA-induced protein.