Archivio Journal of Plant Pathology

Abstract:

Virulence of 36 representative isolates of Fusarium oxysporum f. sp. ciceris causing chickpea wilt, collected from 12 major chickpea-growing states of India was analysed on a new set of 10 differential chickpea cultivars, namely, C 104, JG 74, CPS 1, BG 212, WR 315, KWR 108, GPF 2, DCP 92-3, Chaffa and JG 62 to determine races of the pathogen. Differential cultivars for each races were identified and, based on differential reactions, the isolates were grouped into eight races. Except for the isolates from Delhi, Haryana, Bihar, Uttar Pradesh and Madhya Pradesh, the race groups corresponded to the area of their origin. Genetic diversity of 14 isolates representing 8 races of the pathogen was determined using internal transcribed spacer region of rDNA- restriction fragment length polymorphism (ITSRFLP) and ITS sequencing. ITS1, 5.8S rDNA and ITS2 region was amplified and digested with seven restriction enzymes. Some of the isolates showed area-specific ITSRFLP patterns, whereas others from the same area showed distinct pattern. Thus, the ITS-RFLP pattern was partially corresponding to the area of origin of the isolates indicating the presence of highly variable populations in chickpea-growing areas of the country. The phylogenetic analysis of ITS sequences (JF727559- JF727572) of the isolates included in the present study also grouped them into eight categories and these groups were partially corresponding to the fungal races. Thus, the Indian populations of the pathogen were highly variable in respect of their virulence and genetic characteristics.