Genetic variability, heritability and association studies in bread wheat (Triticum aestivum L.) genotypes

A field study was carried out under rainfed conditions during the growing seasons 2010/11 and 2011/12 in Setif (Eastern part of Algeria) to study the genetic variability, heritability and expected genetic advance for ten traits in 29 bread wheat genotypes. The genotypes showed wide range of variation for all the traits. Genetic coefficient of variation ranged from 1.55 for days to 50% heading to 15.86 for number of spikes per plant. Highest values of heritability were observed for chlorophyll content (60.44%), spike length (63.05%), number of spikes per plant (61.19%), number of grain per spike (67.65%), grain yield (63.96%) and thousand kernel weight (65.35%). The genetic gain ranged from 1.73% for days to 50% heading to 68.55% for number of spikes per plant. The traits plant height, number of spikes per plant and thousand kernel weight showed high heritability and genetic coefficient of variation along with high genetic advance. Results also revealed a positive genotypic association for grain yield with chlorophyll content (0.601), plant height, (0.331), spike length (0.301) number of spikes per plant (0.883), thousand kernel weight (0.468) and harvest index (0.561). Path analysis identified that plant height (1.135) and number of spikes per plant (1.122), exhibited the highest direct effect on grain yield. Therefore, these traits could be considered as suitable selection criteria develop high yielding genotypes.