Genetic Gain through Selection Indices in Hulless Barley

Abstract

In order to study selection indices for improving hulless barley grain yield and its components, 75 F2 plants resulting from the two crosses ICNBF93-369×ICNBF-582 and SB91925×ICB-102607 were evaluated regarding plant height, number of tillers per plant, spike length, number of grains per spike, grain weight per spike, thousand grain weight, days to maturity, harvest index and grain yield per plant. High estimates of heritability in broad sense were recorded for days to maturity, plant height and number of tillers in both populations. Path analysis showed that number of tillers in both crosses and harvest index in cross ICNBF93-369×ICNBF-582 had the most positive direct effects and plant height in both crosses had the highest negative direct effects on grain yield. Assessment of seven different selection indices based on Smith-Hazel and Brim-Williams indices showed that the most genetic advance in grain yield and traits such as number of tillers and plant height was accomplished through a completely new index in which economic values were calculated via multiplication of broad-sense heritability values and values of direct effects of path analysis. The results also indicated that taking advantage of Smith-Hazel and BrimWilliams indices led to almost similar genetic advance in the traits under study. Hence, using the Brim-Williams index is recommended due to simplicity of calculations and interpretation of results, so as to improve the grain yield and its components. © 2011 Friends Science Publishers