Vol.5 : Number 7
Screening and genetic studies of certain maize genotype for resistance to southern corn leaf blight in India

Author(s): Omprakash, Rajesh Singh, Rajeshwar Nandan, Dan Singh Jakhar, KN Chourasia

Southern Corn Leaf Blight (SCLB) incited by Helminthosporium maydis, is a serious disease of Maize. The 53 maize

inbreds were screened for SCLB during rainy season consequently for two year 2013 and 2014. A standard visual scale of 1

to 5 is being used by CIMMYT pathologist was considered appropriate for disease scale. Based on disease scale Percent

Disease Index (PDI) and Area under Disease Progressive curve (AUDPC) considered as disease trait for screening of maize

germplasm as well as estimation of Genetics of SCLB. On an average over four environments 25 resistance, 17 partial

resistances, 3 susceptible lines were identified. In general there were less diseases in E1 (Varanasi in Northern India) than E2

(Nagenhalli in Southern India) though equal load of inoculums were applied in both the cases. Genetics of

Helminthosporium maydis were studied in three crosses viz, CM- 212 (P1) x V- 336 (P2), CM- 212 (P1) x V- 338 (P2) and

CM212 (P1) x CM145 (P2) using Scaling test, Joint Scaling Test and Jinks and Jones (1959) six parameters model. Diseases

scores of P1, P2, F1, F2, B1 and B2 generations of the 3 crosses were used for genetics studies. All the effects (additive,

dominance, additive x additive, additive x dominance and dominance x dominance) were important for expression of SCLB

in all three crosses. Study of generation mean analysis revealed that all three crosses exhibited duplicate type of epistasis.

Thus analysis revealed that SCLB resistance could be population non specific, although various types of gene effects were


Key Words: Resistance, Screening, Southern corn leaf blight, Zea mays L.

Country: India