Qualified Studies on the Pathogenic Variability of Alternaria brassicae, the Causal Agent of Blight Disease of Rapeseed-Mustard

Abstract

Alternaria blight of mustard caused by Alternaria brassicae is one of the major disease which causes an economic yield losses in Uttar Pradesh. Total ten (10) isolates of Alternaria brassicae were collected from different host from different states of India and characterized for pathogenic variations. The incubation period was maximum in Brassica carinata (8.82) followed by B. napus (8.70), B. nigra (7.86), B. juncea (6.00), while it was minimum in B. campestris var. yellow sarson (5.83) for all the isolates. The number of spots per leaf recorded maximum on Brassica juncea (17.66) followed by B. napus (12.66), B. nigra (9.66), B. campestris var. yellow sarson (9.00), while it was minimum in B. carinata (7.66) at 80 days after sowing (DAS). The size of spots per leaf recorded maximum on Brassica juncea (14.89 mm) followed by B. campestris var. yellow sarson (12.48 mm), B. nigra (7.89 mm), B. napus (6.96 mm), while minimum in B. carinata (5.12 mm) at 80 DAS. The number of spots on pods recorded maximum on Brassica juncea (14.66) followed by B. campestris var. yellow sarson (12.66), B. nigra (10.66), B. napus (7.66), and B. carinata (6.33) at 105 DAS. The results revealed that maximum PDI was noted on Brassica juncea (66.70) followed by B. campestris var. yellow sarson (62.99), B. nigra (60.25), B. napus (29.85), while minimum in B. carinata (24.42).