Study of effective traits on grain yield of two and six row barley genotypes (Hordeum vulgare L.) under terminal drought stress conditions

To evaluate terminal drought tolerance in barley genotypes and to study the relationship between morpho-physiological traits and grain yield in terminal drought stress conditions, 214 barley genotypes as well as two checks were examined at three locations; Varamin, Birjand and Esfahan Research Field Stations in 2002 -2003 growing season. Morpho-physiological traits including: days to anthesis, days to maturity, plant height, peduncle length, spike length, number of fertile tillers, grain.spike-1 and 1000-grain weight were measure and recorded in three locations. Results indicated significant differences between Six row and two row genotypes for grain yield components (number of fertile tillers, grain.spike-1 and 1000 grain weight), days to heading and spike length. Correlation, stepwise regression and path analyses studies indicated that days to anthesis, peduncle length and 1000 grain weight not only had the highest correlation with grain yield, but also had the highest direct effects on grain yield in both six row and two row barley genotypes. However, these correlations and effects were more pronounced in two row barley genotypes.