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 p lants is a quantitatively-inherited trait. Quantitative trait loci (QT Ls) can be mapped using molecular markers and recombinant inbred popul ations. This approach has been utilized to investigate the genetic con trol of ABA content in barley (Hordeum vulgare L.). Thirty recombinant inbreds from the Dicktoo x Morex cross, previously characterized by R FLP patterns, were grown in replicated pots and analyzed for ABA conte nt in the leaf under controlled conditions of water deficit. Highly si gnificant differences for ABA content were found among progenies, some of which showed transgressive values over the parental lines. Multipl e regression analysis revealed two significant (P<0.001) QTLs on chrom osomes 2 and 4, which accounted for 58% of the phenotypic variation am ong the recombinant inbreds. The QTL on chromosome 4 peaked near the D HN6 locus, which codes for a dehydrin, an ABA-induced protein.