Components of Genetic Variances, Heritability and Genetic Advance in Maize Lines for Resistance to Northern Corn Leaf Blight in North-west Himalayas

Abstract

The study on components of variances, genetic advance and heritability of northern corn leaf blight (turcicum
leaf blight) was conducted at VPKAS, Almora during 1999-2001. Four susceptible (CM 128, V 327, V 128 and
V 17) and two resistant inbred lines (V 335 and V 13) and their 15 F1s, 15 F2s, 15 BC1s and 15 BC2s, were
generated for study of components of variances, genetic advance and heritability. Additive genetic variance (D),
dominance (H) and environmental variance (E) were more in environment E1 than in environment E2 in most of
the crosses which showed the importance of additive as well as non-additive components and also environmental
variance. The broad and narrow sense heritability varied from cross to cross. However, their magnitude was
higher in E1 than E2. The higher magnitudes of heritability estimates in E1 were encouraging as it offered
viable scope for selection in this environment. The estimates also revealed greater scope of genetic advance in
E1, nevertheless, high genetic advance expressed as percentage of mean were evident for turcicum leaf blight
in both environments. The results showed that all types of gene effects viz., additive, dominance and epistasis
were operating in the crosses in controlling resistance to turcicum leaf blight