Quantitative trait loci controlling agronomic traits in recombinant inbred lines from a cross of oriental- and occidental-type barley cultivars

Abstract

A total of 99 recombinant inbred lines (RILs) generated from a cross between Oriental 'Azumamugi' and Occidental type 'Kanto Nakate Gold' of barley Hordeum vulgare L. cultivars were grown over a period of two years to identify quantitative trait loci (QTLs) controlling agronomic traits such as days to heading, spike characters (length, internode length, awn length and triplet number) and culm internode length. The RILs showed a wide range of variations for all the agronomic traits tested. Composite interval mapping (CIM) enabled to identify a new QTL with a major effect on rachis internode length on chromosome 2HL (qSIL.ak-2H) which was closely linked to the cleistogamy genes and Fusarium head blight resistance QTL. A new QTL for culm length was detected on chromosome 7HL (qCUL.ak-7H), which controlled the elongation, particularly that of the lower culm internodes. The dense spike 1 (dsp1) locus was precisely mapped on a molecular linkage map of chromosome 7HS. The dsp1 locus controlled only the lower culm internode length, while the uzu1 locus controlled the whole culm length. The positions of the QTLs detected in the present study were compared with those of previously reported genes.