STUDIES ON CULTURAL, MORPHOLOGICAL AND PATHOGENIC VARIABILITY AMONG THE ISOLATES OF FUSARIUM OXYSPORUM F. SP. CICERI CAUSING WILT OF CHICKPEA

Abstract

Chickpea (Cicer arietinum L.), one of the major pulses cultivated and consumed in India, is also known as Bengal gram. Chickpea is a major and cheap source of protein (about 17-20%) compared to animal protein. Fusarium wilt of chickpea caused by Fusarium oxysporum f.sp. ciceri is the most serious disease of chickpea. Eleven isolates of F. oxysporum f.sp. ciceri were studied for its cultural, morphological and pathogenic variability. The radial growth of isolates ranged from 72 mm to 87 mm at seven days after inoculation on PDA medium. The isolates, BRFOC-1, BRFOC-4, BRFOC-5, BFOC-3, PFOC-2, and PFOC-3 grow more than 85 mm after seven days of inoculation. Pigmentation is varied among the isolates. Pinkish found in isolates of BRFOC-1, BRFOC-5 and PFOC-2 while pale yellow found in BRFOC-2, BRFOC-4 and BFOC-1 isolates. Sporulation of isolates was profuse to moderate. The size of macro-conidia was ranged from 13-15 x 2-3 µm to 15-19 x 3-4 µm, in micro-conidia was from 3-4 x 1-2 µm to 5-6 x 2-3 µm. The number of septa in macro-conidia was mostly 2-3 and micro-conidia are mostly no septum and some are 0-1. Conidia are hyaline. Shape of most macro-conidia is sickle shape and micro-conidia are round to oval. Pathogenic variability revealed that most of the isolates were highly pathogenic.