EFFICACY OF CITRUS ROOTSTOCKS AGAINST CITRUS CANKER (XANTHOMONAS AXONOPODIS PV. CITRI) INFESTATION

The study was conducted to find out degree of resistance in different citrus rootstocks against citrus canker ( Xanthomonas axonopodis pv. citri ) infestation. Nine different citrus rootstocks were evaluated against citrus canker disease resistance . The role and profile of proteins, proteases, sugars, nitrogen and total phenolic contents were described in the incidence of disease. Disease rating scale having 0-4 range was used to distinguish among resistance and susceptibility of rootstock. Out of nine rootstocks; three rootstocks (Fraser hybrid, Cox mandarin hybrid and C-35) were resistant, three were found moderately susceptible ( Poncirus trifoliata , Troyer citrange and Carrizo citrange ) and three ( Cleopatra mandarin , Rough lemon and Benton) were susceptible. Biochemical analysis revealed that there was an increasing trend in the citrus canker disease incidence with total sugars contents while in case of total phenolic contents, protein and protease activity, decreasing trend was observed in disease incidence in all the rootstocks. It is suggested that the resistant rootstocks could be used in breeding to produce the resistant citrus cultivars against citrus canker disease.