Biochemical factors in powdery mildew resistance of ber (Zizhyphus mauritiana Lamk.) genotypes varying in ploidy levels

Abstract

The defence of a plant to a disease may not depend so much on its structural barriers as on the metabolic process before and after infection. The genetic constitution of the resistant host may be capable of producing or withholding a particular chemical substance or group of substances which interfere with the growth and multiplication of the pathogen [1]. There are two types of defence mechanisms viz., pre infectional and post infectional [2]. The pre infectional resistance is mainly governed by the level of certain metabolites and the post infectional resistance is induced as a result of infection by pathogen. Chemical constituents like total soluble solids [3], sugars [4] and chlorophyll [5, 6] are related with resistance to powdery mildew.