Bioefficacy of bacteria and yeast bioagents on disease suppression and quality retention of stored Kinnow mandarin fruits

Kinnow mandarin is a high value citrus crop in the fruit industry. However, the fruits are vulnerable to a variety of phytopathogens and suffer huge quantitative and qualitative losses. Pathogenic filamentous fungi like Penicillium digitatum, Penicillium italicum, and Geotrichum candidum are mainly responsible for postharvest losses. Alternative to synthetic fungicides, the bacteria and yeast-based biocontrol approaches are the most efficient means for controlling postharvest diseases. The antagonistic potential of five biocontrol agents such as Debaryomyces hansenii, Lactobacillus plantarum, Metschnikowia pulcherima, Pichia guilliermondi and Rhodotorula minuta var. minuta was assessed under both in vitro and in vivo conditions against the mycelial growth of postharvest pathogens using dual culture method. The results revealed that R. minuta var. minuta was the most promising antagonist with 71.98%, 76.18% and 67.46% mean mycelial growth inhibition of P. digitatum, P. italicum and G. candidum respectively, over untreated potato dextrose agar (PDA) plates after 192 h of incubation under in vitro. Further, under in vivo, the fruits treated with R. minuta var. minuta did not impair the quality and sensory attributes during ambient storage. Hence, R. minuta var. minuta proved an eco-friendly and safer substitute to synthetic fungicides for postharvest disease management of Kinnow mandarin fruits.