Evaluation of genetic parameters of winter barley varieties under water deficit conditions

The aim of the present study was to use REML/BLUP-based procedures in order to estimate variance components and genetic parameters and to determine correlations between grain yield and yield-related traits of winter barley varieties. Studied genotypes were grown in two seasons characterized by different levels of water deficit (precipitation sum was less by 15% in the first growing year and 36% in the second growing year than the long-term precipitation sum). A reduction was observed in all studied yield-related traits, with grain yield in the second year being more than 70% lower than that measured in the first growing year. Lower values of broad-sense heritability in the second growing year for the traits number of spikelets and grains per spike, grain weight per spike, and grain yield were found suggesting that the direct selection of these traits under drought stress conditions will be less effective. Varieties ranking based on the FAI-BLUP index strongly varied across growing seasons, but in both years variety Bojin was selected as a highperforming variety for multiple traits. Considerable differences were observed in the magnitude and directions of correlations between grain yield and yield-related traits between two growing seasons. These findings, in the context of the increasing frequency and duration of drought stress in the region, suggest a longer period of multi-year testing and complicate the process of selection in breeding programs of winter barley.