Variability studies on Fusarium sp. complex causing Pigeonpea wilt in India

Abstract A total of 50 Fusarium isolates were collected from major pigeonpea growing states of India and studied for cultural and morphological characteristics. Among 50 isolates, a total of 30 isolates were selected based on their cultural and morphological characteristics and studied for pathogenic variability on eight pigeonpea (ICP8858, ICP 8859, ICP 8862, BDN-2, ICP 9174 ICP 8863, ICP 2376 and BAHAR) differential genotypes. Among the eight genotypes, the four genotypes, namely, ICP8858, ICP 8859, ICP 8862, BDN-2 reacted differentially to isolates and were not consistent in their pathogenicity; however, two genotypes, ICP 9174 and ICP 8863, exhibited resistance reactions, and two genotypes, ICP 2376 and BAHAR, exhibited consistent susceptibility to wilt disease and could differentiate the 30 Fusarium isolates into six pathogenic variants (0, 1, 2, 3, 4 and 5). Among the 6 variants, the maximum distribution of Fusarium variants was observed in Bihar and Telangana (4 variants in each state), followed by Andhra Pradesh, Karnataka Uttar Pradesh and Maharashtra (2 variants) and one variant each in New Delhi and Jharkhand states. ITS-rDNA sequencing of 23 Fusarium isolates revealed that Fusarium udum (65.21) was the dominant species causing pigeonpea wilt in India, followed by Fusarium solani (21.7) and Fusarium equiseti (13.04). The results of the present study were notable in terms of Fusarium variants, which might be used to deploy location specific wilt-resistant cultivars for improved disease management tactics. This study will also aid in the development of broad-based pigeonpea wilt resistant varieties to suppress potential epidemics.