Evaluation of maize inbred lines (yellow) for slow leaf blighting mechanism

摘要

Turcicum leaf blight (Exserohilum turcicum (Pass) Leonard and Suggs. Helminthosporium turcicum (Pass) is prevalent in all the major maize Syn. (Zea may. L) growing regions of Peninsular India during rainy/kharif as well as winter (rabi) seasons, Himalayan region during the rainy season and Indo-Gangetic plain particularly Bihar during the winter season. This is major disease in areas where the temperature drops at night, while the humidity is high. The disease is known to affect maize from seedlingstage till harvest. Loss in grain yield will be more if it occurs at flowering, silking and grain filling stages. The lesions produced on the leaves of susceptible plants are normally large (4 to 20 cm. long and 1 to 5 cm wide) elliptical in shape and greyish green to tan in colour. Growth of the pathogen in the host is quantitatively reflected with the disease symptom by which the resistance is often measured. Rate reducing resistant cultivars are identified by assessing the proportion and time of appearance of disease, the less and late they become visible, the higher will be their partial resistance. This paper reports evaluation of new inbred lines for slow blighting character.