Biochemical Basis of Resistance against Maruca vitrata (Geyer) in Urd bean^*

Six biochemical parameters, viz., total sugar, reducing sugar, non-reducing sugar, amino acids, proteins and phenols in pods were studied in relation to the expression of varietal reaction to Maruca vitrata in ten varieties of urd bean. Highly susceptible cultivar LBG-17 had highest amount of total sugar (1.42 mg/g), reducing sugar (0.62 mg/g), non-reducing sugar (0.80 mg/g), amino acids (0.13%) and protein (24.3%) as compared to highly tolerant cultivar LBG-611 which had 1.2mg/g, 0.50 mg/g, 0.70 mg/g, 0.07% and 21.6%, respectively. Whereas, phenols were highest (21.72 mg/g) in resistant cultivar LBG-611 than the susceptible cultivar LBG-17 (20.41 mg/g). There was a significant and positive correlation existed between total sugar, reducing sugar, non-reducing sugar, amino acids and proteins with pod damage whereas negative correlation prevailed between phenols contents in pod with pod damage. Free choice arena test also confirmed that highest larval orientation was observed in LBG-17 (susceptible) both in pods (19%) and flowers (14%) than the tolerant cultivar (LBG-611).