Changing pattern of seed-associated fungi in urd bean (Vigna mungo (L.) Hepper): A study of diversity and abundance

Urd bean (Vigna mungo (L.) Hepper), being a highly nutritious pulse crop has been facing a gradual decline in production and productivity in recent years due to reduced germination percentage and seed vigor, because of the seed-associated pathogenic mycoflora. Studies on seed-associated mycoflora are vital for the early detection of seed-borne pathogenic fungi, allowing for the development of sustainable agricultural strategies to increase production. The present study aimed to decipher the diversity of seed-borne mycoflora associated with urd bean seeds. Twenty seed samples collected from the farmers’ fields were analyzed using the standard blotter and agar plate methods. The fungal genera identified based on morphology include Fusarium, Macrophomina, Aspergillus, Penicillium, Trichoderma, Lasiodiplodia, Choanephora, and Diaporthe. The agar plate method resulted in a higher diversity of mycoflora than the standard blotter method. Fusarium and Macrophomina were the predominant mycoflora, with relative abundances of 84.25 % and 6.83 %, respectively and were identified as F. incarnatum and M. phaseolina at the species level. The percentage frequency of association of predominant mycoflora was higher on the seed coat, followed by the cotyledon and plumule-radical axis. The effects of isolated mycoflora on seed germination and seedling vigor were studied using a sterilized potting mixture. The lowest seed germination rate was noticed in the case of seed inoculated with Fusarium, followed by Macrophomina. Our findings may provide valuable insights into the evolving diversity patterns which further helps identify emerging diseases.