Impact of Alternaria alternata on the physiological and yield-related traits of Vigna radiata

This study examined the effects of the phytopathogenic micromycete Alternaria alternata on leaf pigments, total water content in leaves, exchange leaf water retention, transpiration rate in the flowering and podding period and yield-related traits in three replicates of mung bean (Vigna radiata) varieties. The chlorophyll a, chlorophyll b and carotenoid contents in leaves were comparatively assessed under infected (spray inoculation) and control conditions during the flowering and podding periods. The results indicated that A. alternata significantly reduced pigment content in most varieties. The Durdona and Andijon-1 varieties exhibited the greatest reduction in pigment content, while Barqaror and Baraka varieties showed the least sensitivity to A. alternata. Infection with A. alternata in mung bean varieties caused a decline in transpiration and water retention, likely due to stomatal closure and tissue damage. However, total water content generally increased, suggesting water accumulation in healthy tissues as a stress response. Regarding yield-related traits, the number of pods per plant, 1000-grain weight and total grain weight were reduced to varying degrees across all varieties under effect of A. alternata compared with the untreated control plants. A significant decline in yield was notably observed in the Durdona, Zilola and Marjon varieties. This study, for the first time, demonstrates the differences in physiological responses among mung bean varieties by jointly examining the effects of A. alternata on leaf pigment content, water exchange and yield across various cultivars. The findings obtained serve to protect mung bean and other leguminous plants from the influence of A. alternata in agriculture and increase their yield.