Gene Effects Controlling Heritability of Downy Mildew Resistance in Nigerian Elite Pearl Millet Lines

Downy mildew disease caused by the fungus Sclerospora graminicola Schroet, causes yield losses across the millet growing zones of Nigeria. Identification of the source of resistance and gene actions controlling resistance is useful in developing appropriate breeding strategies. Therefore there was need to study downy mildew resistance in Nigerian elite pearl millet lines. Five pearl millet parental lines; BUDUMA, SOSAT-C88, LCICDMR36-4, 20B-2 and 25B-4 were obtained from Lake Chad Research Institute, Maiduguri. From this five parents, using factorial mating scheme of North Carolina Design II, F s, F s BC P s and BC P s 1 2 1 1 1 2 were generated during November, 2004 May, 2005. The five parents, twenty-four crosses and one check (7042 S), were evaluated using Randomized Complete Block Design with three replications at the downy mildew field nursery of Lake Chad Research Institute and the Experimental Farm of the Department of Crop Production and Horticulture, Federal University of Technology, Yola during 2005 and 2006 cropping seasons. Downy mildew resistance from this study was found to be influenced by dominant gene effect, because the ratios of dominance to additive variance values were more than unity for both incidence and severity index. Narrowsense heritability was moderately high, 66.06% for downy mildew incidence and 52.41% for downy mildew severity, indicating that there is the likelihood that improvement can be achieved by using these genotypes.