Quantitative trait loci for grain yield and yield components in a cross between a six-rowed and a two-rowed barley

The positions of quantitative trait loci (QTL) for yield and yield components were estimated using a 85-point linkage map and phenotype data from a F1-derived doubled haploid (DH) population of barley. Yield and its components were recorded in two growing seasons. Highly significant QTL effects were found for all traits at several sites in the genome.

A major portion of the QTL was found on chromosome 2. The effect of the alleles in locus v on thousand grain weight and kernels per ear explained 70–80% of the genetic variation in the traits. QTL × year interaction was found for grain yield. Several different QTL were found within the two-rowed DH lines compared to those found in the six-rowed DH lines.

Epistasis between locus v and several loci for yield and yield components indicates that genes are expressed differently in the two ear types. This may explain the difficulties of selecting high yielding lines from crosses between two-rowed and six-rowed barley.