Vol. 8, Issue 10, Part R (2024)

Cauliflower (Brassica oleracea var. botrytis) is one of the important vegetable crops in India and belongs to cruciferous family. The cauliflower leaf spot has caused significant losses in all most all cauliflower growing countries along with India. The area of cquliflower is increasing every year at east Nimar Khandwa of Madhya Pradesh. The incidence of Alternaria leaf spot was noticed all over the nimar region up to 13.98 %. A roving survey was conducted in the visinity of Khandwa and collected the pathogen and studied Cultural and Morphological Variability of Alternaria brassicicola during kharif 2022-23. The four mycellial growth pattern were noted viz. cottony, concentric cottony, fluffy cottony and appressed. Isolates are also screened for colony colour and four major colony colour viz. Greyish White, White, Black and Greyish black were noticed. The pigmentation released by the mycellial growth in PDA Medium into 3 categories viz., Light Brown, Brown and Dark Brown with different isolates. The pathogen profusely branched, brownish, septate mycelia. Conidia arose singly or in groups and were simple or branched. Conidia formed in long chains often branched, oval to ellipsoidal with 2-7 Horizontal and 1-4 vertical septa. Overall length of conidia ranged between 28-68 μm, while width at broadest part of conidia ranged between 4-12 μm and beak of 4-10 μm. the maximum Length and Width of isolates found different in each isolates, the highest observed in UKC-2 (68 x 12 μm), followed by UKC-1 (55 × 10 μm), UKC-4 (49 X 9 μm), while minimum size of conidia was UKC-5 (28 × 4 μm) followed by UKC-6 (35 × 6 μm), UKC-3 (44 x 7)and in terms Septation of conidia (Horizontal septa & vertical septa) conidia is observed different in each. The highest Septation observed in UKC-2 (7 & 4), followed by UKC-1 (6 & 4), UKC-4 (6 & 3), while minimum size of conidia was UKC-5 (2 × 1) followed by UKC-6 (3 & 1), UKC-3 (5 & 2).