QTL analysis of tolerance to spring radiation frost in barley

Abstract

Spring radiation frost can cause significant losses in yield and a reduction in malting quality of barley (Hordeum vulgare L.) throughout southern and western Australia.Progress in breeding for frost tolerance has been slow due to large errors resulting from environment and genotype factors confounding selection. Quantitative trait loci (QTL) analysis can aid to remove the effects of confounding factors such as maturity and plant type from intrinsic frost tolerance. The Arapiles x Franklin mapping population was screened in the field for its susceptibility to frost damage. Sterility and grain damage were mapped and the Franklin alleles at the eps2 region on 2HS (late flowering) and denso dwarfing region on 3HL significantly contributed to frost tolerance. When a subset of genotypes were selected based on a narrow maturity range, a significant QTL for frost damage was identified on the long arm of chromosome 5H close to Sh2. This region has been previously associated with the expression of winter hardiness in barley. It is also homoeologous to the region where Fr1 (frost tolerance) is located in wheat. These findings have prompted further investigation into the significance of the 5HL region in other mapping populations, particularly those of winter x spring crosses. If the affect of the QTL in this region can be validated, it may be possible to use marker assisted selection to improve frost tolerance of Australian barley.