Cultural and morphological variability among Trichoderma harzianum and Trichoderma asperellum collected from chickpea growing areas of Rayalaseema Region of Andhra Pradesh

The genus Trichoderma contains species of great economic importance due to their ability to act as biological control agents against a broad range of fungal plant pathogens. In the present study ten isolates of Trichoderma species were isolated from rhizospheric soil of chickpea growing areas of Rayalaseema Region, Andhra Pradesh. The isolates were characterized on the basis of their cultural and morphological characteristics. Out of 10 isolates, 5 isolates were identified as T. asperellum and 5 isolates as T. harzianum. Cultural Characteristics T. asperellum isolates were fast growing with light green to dark green fluffy granular growth, mottled with white flecks and often with inconspicuous wefts of yellow hyphae whereas T. harzianum isolates were relatively slow grower, with green to dark green coloured colony and effuse conidiation in different media. The size of phialides of T. harzianum isolates KNO 9 recorded 7.8-9.7 × 3.3-4.3 μm while the highest size of phialospores 3.5-4.0x 2.5-2.8 μm recorded by ATPU 2. The size of phialides of T. asperellum isolate was highest recorded in KNP 1 with 5.3-8.2 × 1.2-1.6 μm , while the size of phialospores was observed in KJ 12 with 2.1-3.5 × 1.6-2.0 μm. The chlamydospores sizes was more in KJ 12 with 9.5 - 13.3 × 8.2 - 9.4 μm.