Genotypic variation in biochemical compounds of the Sri Lankan tea (Camellia sinensis L.) accessions and their relationships to quality and biotic stresses

Tea (Camellia sinensis L.) is well known for its biochemical constituents that define the product quality and confer pest and disease resistance. Seven major metabolites – epicatechin (EC), epicatechin gallate (ECg), epigallocatechin (EGC), epigallocatechin gallate (EGCg), caffeine, theobromine, and gallic acid – of 87 beverage type and six non-beverage type tea accessions from Sri Lankan tea germplasm were profiled using HPLC and LC-MS/MS. All seven metabolites varied widely in the beverage type accessions. The non-beverage types only contained gallic acid and epicatechin. Results prove the presence of high EC and ECg contents in green leaves to be a reliable marker for identifying high-quality black tea-producing accessions. High EC and low EGCg contents in green tea leaves appear to enhance traits of resistance to blister blight disease. Significant variations detected in theobromine, caffeine, and total polyphenol content define the affinity of germplasm to the main three tea taxa, and we conclude that C. sinensis ssp. lasiocalyx predominates the Sri Lankan germplasm collection.