Studies on Cultural and Morphological Variability Among the Isolates of Fusarium incarnatum (Desm.) Sacc., Incitant of Wilt in Crossandra

Fifteen isolates of Fusarium incarnatum (Desm.) Sacc., incitant of Crossandra wilt were studied for its cultural and morphological variability. The F. incarnatum isolates, F-ISO-3, F-ISO-4, F-ISO-5. F-ISO-9, F-ISO-10, F-ISO-11 and F-ISO-12 grew more than 8.5 cm after 10 days of inoculation and considered as fast growing category. Among all the isolates, F.incarnatum, F-ISO-1 and F-ISO-7 isolates showed significant variation in radial growth (less than 4.5 cm) on PDA medium and they were considered as slow growing category. The size of macro conidia ranged from 19.45 x 2.36 to 24.43 x 3.16μm and the size of micro conidia ranged from 6.45x 1.90 to 7.43 x 2.42μm. The number of septa in macro conidia and microconidia are 3–5 and 0–1, respectively and both the conidia are hyaline. The macro conidia is spindle or sickle shaped with or without blunt ends and micro conidia is pyriform to oval or round to oval shape. Chlamydospores are globose, intercalary, solitary or in chains and observed in all the F. incarnatum isolates.