Abstract

Some hulless barley varieties have been reported to be associated with poor vigour, which can limit their yield and make them unattractive to growers. A study was conducted to determine the linkage relationship of the locus nud conditioning hullessness and other loci controlling the expression of the seedling vigour related traits. Recombinant inbred lines (RILs) were generated from a cross between spring type varieties with contrasting seedling vigour. These two parental lines differ in seedling growth habit, with 'CDC Cowboy', a hull type (N/_), possessing superior seedling vigour and 'CDC Rattan', a hulless type (n/n), exhibiting poor seedling vigour. Early vigour was assessed as leaf areas and specific leaf areas at the 3rd leaf stage. The traits considered to contribute to early vigour were: leaf width, leaf area, leaf dry weight, and specific leaf area of the first and second leaves. Each of the traits showed continuous variation among the hulless RILs. Transgressive segregation was distinctly observed for all traits. Canonical discriminant analysis (CDA) revealed that the hullessness, controlled by the recessive gene (n/n), may not have an epistatic effect on several other loci, including those controlling the expression of seedling vigour related traits. This suggests that it is possible to develop hulless types of barley varieties with improved seedling vigour. The present study represents the first step in development of a marker-assisted breeding effort to improve early-season performance in hulless barley.

Keywords: Barley, seedling vigour, heritability, genetic variability, hulless gene, recombinant inbred lines (RILs)