MELHORAMENTO DO TRIGO: XXXI. HERDABILIDADES E CORRELAÇÕES ENTRE TRÊS CARACTERÍSTICAS AGRONÔMICAS EM POPULAÇÕES HÍBRIDAS

Aiming at estimating broad and narrow sense heritabilities for plant height, number of grains per spikelet, grain yielding potential, and phenotypic correlations among these characters, crosses were made between a tall Brazilian cultivar BH-1146 (P1), and three semidwarf Mexican cultivars CMH 80.638/CMH 75 A.411//CMH 80.638 (P2); CMH 79.958/2 * CNO 79 (P3) e CMH 79.481/CMH 77 A. 917 (P4). Hybrids seedlings from F1, F2, and backcross generations were transplanted in pots under greenhouse conditions in which the agronomic traits were evaluated. For plant height broad and narrow sense heritability estimates on a single plant basis showed high values, for all crosses (0.86 to 0.91 and 0.77 to 0.96), respectively. As to grain yielding potential, the broad and narrow sense heritability estimates were moderate (0.41 to 0.62) to high (0.63 to 0.70), while for number of grains per spikelet these values were low (0.26 to 0.50) to moderate (0.26 to 0.61). Significant phenotypic correlations were detected between grain yield and plant height for the crosses P1 x P3 (-0.19 P < 0.05) and P1 x P4 (0.62 P < 0.01), and between grain yield and number of grains per spikelet for the same crosses. Associations between plant height and number of grains per spikelet were positive and significant for P1 x P2 and P1 x P4. The results strongly suggest the fesibility of selecting semidwarf and high yielding genotypes with a high number of grains per spikelet, in the cross P1 x P3.