Change in leaf epicuticular wax and biochemicalsecondary metabolites in cocoa (theobroma cacao l.) under Hydric stress

Cocoa (Theobroma cacao L.) is continuously being exposed to frequent fluctuations in weather conditions during its crop cycle. Plants in general, adapt to these varying weather conditions by adopting different methods with morpho- physiological traits and with secondary metabolites. Biochemical constituents of cocoa leaves of different genotypes were studied in relation to two watering regimes represented by normal irrigation (100% of field capacity) and hydric deficit stress (20% of field capacity) conditions. Concentrations of leaf epicuticular wax, total soluble sugars, free amino acids, proline and proteinsshowed high genotypic variability due to the implementation of the watering regimes. Leaf epicuticular wax, cytosolic total soluble sugar and proline contents increased during hydric deficit stress whereas, cytosolic free amino acid and protein contents decreased during 20% FC level. The pattern of accumulation of these biochemical constituents varied among cocoa genotypesby the influence of hydric stress. Cocoa genotypes VTLCP-26, VTLCP-27, VTLCP-25, VTLCH-4 and VTLCP-22 with more accumulation of these compounds exhibited wider adaptability. The results indicated possible role of biochemical compounds in cultivar adaptability to hydric deficit stress, which can be exploited for screening of cocoa germplasm for drought.