Biochemical Changes in Groundnut (Arachis hypogaea L.) Infected by Stem and Pod Rot Disease caused by Sclerotium rolfsii Sacc

Peroxidases (POD), poly phenol oxidases (PPO) and phenyl alanine ammonia lyase (PAL) from healthy and Sclerotium rolfsii inoculated stems of 6 genotypes of groundnut were estimated after 3 days of inoculation. The activity of PO, PPO and PAL began from 3rd DAI and gradually increased up to 6 th DAI and thereafter declined. PO, PPO, and PAL activity was more in infected stem sample compared to healthy stem. Among the genotypes resistant and moderately resistant genotypes recorded maximum PO, PPO and PAL activity whereas susceptible genotypes recorded less activity. Further, biochemical constituents of healthy and stem rot infected tissues of different genotypes of groundnut were evaluated. The results revealed that total sugar content was more in resistant genotypes (12009 and 17110), moderately resistant genotypes (17159 and 17169) when compared to highly susceptible genotypes (TMV-2 and KRG-1). Further, it is also found that healthy stems of groundnut recorded more sugar, reducing and non reducing sugar content compared to diseased stems. Phenol and protein contents in healthy and infected stems varied among genotypes. Phenol and protein contents were more in infected stem as compared to healthy stem. Further, resistant and moderately resistant genotypes showed more contents of phenol and protein than susceptible genotypes.