Abstract
Genetic analysis of narrow- sense earliness in wheat was carried out, by using four segregating populations derived from the crosses between five cultivars with a large variation in narrow-sense earliness. Narrow-sense earliness measured at 15 °C, exhibited a large variation among five parental cultivars ranging from 29.8 to 51.2 days. It was earlier in F1 hybrids than in the mid-parent and later by a few days than in the early parent in all cross combinations, indicating the partial dominance of earliness. The polygenic nature of narrow-sense earliness was indicated by continuous variation in F2 populations, and heritability in a broad sense ranged from 0.90 to 0.99 among four F2 populations. In randomly selected progenies, the parent-offspring correlation coefficient between parents (F2 plants) and F3 lines proved to be statistically significant (r=0.608-0.742, P<0.01). These results indicated that narrow-sense earliness is a highly heritable character, inspite of its quantitative nature. Artificial selection in F2 populations resulted in significant improvement in early and late selections as compared with randomly selected F3 lines, indicating the effectiveness of artificial selection for optimizing narrow-sense earliness.
