Effect of A1 cytoplasm on the combining ability for smut severity in pearl millet.

Among the various available sources of male-sterile cytoplasm in pearl millet [Pennisetum glaucum (L.) R.Br.], the A1 source has been exploited the most for the breeding of commercial F1 hybrids. The effect of this source on the combining ability (CA) for smut severity was studied since it is the CA that determines the performance of hybrids. The effect was estimated by comparing the CA estimates of 5 pairs of lines and 35 pairs of crosses with and without A1 cytoplasm. The cytoplasm showed either a significantly desirable or at least no adverse effect on the CA of 4 out of the 5 line pairs and 56 out of 70 pairs of comparison of crosses in two environments. The differential effect of cytoplasm in some pairs might be due to its interaction with nuclear genes. These results further substantiated that the A1 cytoplasm is not linked with increased smut severity in pearl millet hybrids.