Heritability and correlations among agronomic characteristics in durum wheat hybrid populations

Narrow sense heritability values were estimated for number of spikes per plant, number of grains per spike, hundred kernel weight and grain yield, as well as environmental, phenotypic and genetic correlations among them. The studies were made for crosses among durum wheat genotypes P19 (P-1) and P33 (P-2), originated from the Instituto Agronomic de Campinas (IAC) breeding program, and IAC-1003 (P-3), genotype introduced from the International Improvement Center of Mayze and Wheat Breeding (CIMMYT), Mexico. Low narrow sense heritabilities estimations were obtained for the character number of spikes per plant (0.23 to 0.38), except for the cross P-1 x P-2 (0.77). Low values also were obtained for number of grains per spike (0.13 to 0.31), except for the cross P-1 x P-3 (0.77). For the character hundred kernel weight, the values varied from medium to low (0.24 to 0.49) for all crosses and the same has occurred for grain yield (0.09 to 0.45), suggesting that the selection for all characters in most crosses should be done at last generations. Phenotypic correlations between grain yield and the other evaluated characters were all positive and significant indicating that plants with higher number of spikes, higher number of grains per spike and with heavier grains would be the highest yielding ones.