Correlation of oxalic acid and virulence pattern among the isolate of Sclerotinia sclerotiorum

Rapeseed-mustard group of crops are the major Rabi oilseed crops of India. The group is mainly comprises by Brassica juncea, B. napus, B. rapa, and B. carinata. Among rapeseed-mustard genotypes, B. juncea is the most important oilseed crop of Grid zone of Madhya Pradesh covering Morena, Bhind, Gwalior, Sheopur, Guna, Shivpuri, and Ashoknagar districts majorly contributing more than 80% share in the production of mustard in the state. Sclerotinia sclerotiorum isolates of grid zone in Madhya Pradesh differed significantly in oxalic acid production. Maximum oxalic acid was produces by Morena isolate (3.52 ug mg¹mycelium) followed by Bhind (2.88 ug mg⁻¹ mycelium), Sheopur (2.54 ug mg⁻¹ mycelium), Gwalior (2.52 ug mg⁻¹ mycelium), Shivpuri (1.74 ug mg⁻¹ mycelium) and Guna (1.42 ug mg¹ mycelium), while the minimum oxalic acid production was recorded in Ashoknagar isolate (1.34 ug mg⁻¹ mycelium). Further the mycelial growth showed a highly significant and positive correlation with the oxalic acid production.