Morphological and cultural variability of Fusarium spp. causing wilt in chilli in Karnataka

Abstract

Morphological and cultural variability was studied among the isolates of Fusarium spp. collected from fusarium wilt infested chilli fields of north Karnataka. The isolates cultured on potato dextrose agar medium showed considerable cultural variabilities in colony diameter, colony morphology, pigmentation and morphological variabilities in conidial size, septation and sporulation rate. Colony diameter among F. oxysporum isolates ranged from 63.93- 89.87 mm and produced white fluffy cottony growth with orangish pigmentation. The isolates produced macro conidia of size 11.5-24 × 2.2-5.5 µm with 3-4 septation, micro conidia of size 5-6 × 2.7-3 µm and chlamydospore of size 10.5-11.2 µm in diameter. Colony diameter among F. solani isolates ranged from 57.80-89.87 mm, and produced white-creamish cottony/fluffy/submersed growth with creamish, light orangish, purplish and pinkish pigmentation. The isolates produced macro-conidia of size 10-25.5×3-6.5 with 2-3 septation, micro-conidia of size 5-12.5×2.1-3.5 µm and chlamydospores of size 10-12 µm in diameter. The isolates also showed variation in sporulation rate.