Selection for downy mildew resistance from the regenerants of pearl millet

Abstract

Plants were regenerated from the inflorescence explants of three B lines of pearl millet showing different degrees of susceptibility to downy mildew disease. Plants were regenerated from the embryogenic callus cultures and grown to maturity in the vicinity of other downy mildew infected plants. Progenies of disease free (R0) plants were screened for two successive generations in the disease plots. Three somaclones of 23 B (highly susceptible genotype with 97% disease incidence) showed increased level of resistance. Four disease free somaclones were obtained each from 81 B (susceptible with 15% disease incidence) and 841 B (resistant with 7% disease incidence) genotypes. When the populations of these somaclones were screened for some agronomic characters, a significant increase was observed in the population means for plant height and panicle length in two genotypes. The results manifest the genotypic differences in the extent of somaclonal variation for disease resistance and also for agronomic traits. The variants selected as downy mildew resitant were individually compared with their respective control plants for agronomic traits. Two downy mildew resistant variants retained the original characters. Thus, the present study demonstrated the existence of somaclonal variation for downy mildew resistance and some agronomic traits in pearl millet.