Evaluation of Indian mustard against Alternaria blight.

摘要

The common Indian mustard cultivars, Mahyco Bold, Rohini, Alankar, Swarna, Varuna, Pusa Karishma, Pusa Bold, BS-2, Kalamoti and Kranti procured from authorized dealer in Aligarh were found infected with Alternaria brassicicola and A. brassicae, former being highly dominant occurring singly and concomitantly while A. brassicae was found mostly in concomitant infestation. Due to dominant occurrence of the species, germplasm was screened against A. brassicicola using artificial inoculation by spraying foliage with pure spore suspension of the fungus. The fungus inoculation resulted to necrotic lesions on 15-70% leaves, stem and/or pods of all the cultivars tested. Development and progress of the blight was slower in Alankar (15-23%) followed by Kalamoti (16-25%) and Kranti (18-28%). All cultivars screened were found susceptible to A. brassicicola as inoculation with the fungus resulted to significant decline in the yield of all cultivars being greatest in cv Pusa Karishma (50%) followed by Kalamoti (46%) and lowest in Kranti (14%) in comparison to uninoculated control. Highest population of the fungus was recorded on leaves (20.0-37.0x105 spores/cm2) followed by stem (8.0-15.0x103 spores/cm2) and pods (4.0-14.0x103 spores/cm2) and lowest on seeds (1.0-3.0x102 spores/seeds). Two cultivars viz., Kranti and Alankar were found less susceptible to A. brassicicola and can be cultivated in a situation of non availability of resistant/tolerant cultivars.