Cultural and morphological variability among Fusarium oxysporum f.sp. lycopersici causing wilt of tomato in south Gujarat region

Abstract

An experiment was carried out to study the variability using 10 isolates of Fusarium oxysporum f.sp. lycopersici collected from different tomato growing areas of south Gujarat. Studies were made on cultural and morphological variation like mycelial colour, mycelial growth, dry mycelial weight, sporulation, conidial size and formation of chlamydospores. The isolates produced moderate, profuse fluffy, thin flat to slight fluffy and submerged growth with white, yellow, light pink, dark pink, orange and purple–orange pigmentation. Sporulation varied from 2.77 × 106 to 21.68 × 106 spores/ml. The maximum dry mycelial weight was observed in SGFOL-6 (193.33 mg), whereas the minimum dry mycelial weight was observed in isolate SGFOL-9 (120.67 mg). Dry mycelial weight varied from 55.33 to 88.33 mm. The size of macroconidia ranged from 15.46–21.8 × 4.91–5.45 to 21.42–44.28 × 7.35–9.14 μm with 1–6 septa in different isolates. The size of microconidia varied from 3.57–14.28 × 2.68–4.46 to 7.14–14.28 × 3.57–5.35 μm with 0–1 septa in different isolates.