Vol. 10, Issue 6 (2021)

Author(s):
Sunna Deepti, Mudadla Hareesh and Dr. HC Lal

Abstract:
The present investigation was carried out in the research farm as well as laboratory of Birsa Agricultural University, Kanke, Ranchi on variability in Fusarium oxysporum f.sp. udum causing wilt of Pigeonpea and its management. The systematic study revealed that wilt disease in Pigeonpea was found to be infected with Fusarium oxysporum f.sp. udum at all ten locations surveyed in 2015-16 and 2016-17. Morphological studies of Fusarium oxysporum f.sp. udum revealed that the dimensions of macro condia, micro conidia and chlamydospores shows larger variations among different isolates. The cultural characters observed on PDA medium and the mycelium colour was in white and pinkish at the center with dense to fluffy growth. The size of mycelial width varied from 3 μm (Fou-Bor -4) to 6.32 μm (Fou – Ran - 4). Where as microconidia were small, oval in shape and hyaline in colour, unicellular or with one or two septa, and measures in the range of size between 6.00 × 2.10 μm (Fou-Ran- 4) to 10.80 × 3.00 μm (Fou- Kok-1). The macroconidia were long, curved, sickle shaped, pointed at the tip, hyaline in colour and knotched at the base, septated (2-4 septa) and measured between 19.05 × 3.25 μm (Fou- Hoc-4) to 28.70 × 2.50 μm (Fou- Kok-1). Chlamydospores with spherical in shape and hyaline in colour and it’s dimensions also varied in all 40 isolates of the pathogen. Chlamydospores dimension varied from 8.20 × 7.92 μm (Fou- Buk – 2) to 11.35 × 8.20 μm (Fou-Nag-3). Spore density also varied between conidia per ml of culture under 10 x microscopic field, it is varied for macro conidia in the range of 6 to 13, micro conidia it is between 20 to 42 and chlamydospores it is between 2 to 8 number per ml.