Analysis of variability determinants in Alternaria-Brassica-interactions

Abstract

The pathogenic variability in four species of Alternaria is reported to be governed by determinant attributes
viz., pathological, symptomatological, morphological, cultural, nutritional, biochemical, genetical, molecular,
proteome level, thermo, and fungicidal sensitivity. Initially, observations on variability in cultural
characteristics and pathogenesis of different isolates of Alternaria were made in A. brassicicolavegetables,
A. brassicae–Brassica and A. raphani–radish host –pathosystem. A. alternata strains, from
Crambe showed differences in their physiological and pathological characteristics; strain B was most
virulent, strain A was moderately virulent, and strain C was least pathogenic on Crambe. Three races of
A. brassicae viz., RM-1, RM-2 and V-3 virulent on rapeseed-mustard group of crops were identified. While
race RM-1 was avirulent only on B. oleracea var. Capitata, race RM-2 was avirulent on both B. oleracea
var. Capitata and B. oleracea var. Botrytis. Race V-3, from vegetable crops was most virulent on the all
host differentials. Thirteen A. brassicae isolates evaluated on selected winter rape cultivars differed in their
virulence.