Molecular profiling and development of DNA marker associated with drought tolerance in tea clones growing in Darjeeling

Amplified Fragment Length Polymorphism (AFLP) fingerprints were developed for 29 Darjeeling-grown tea clones. AFLP diversity estimates based on Jaccard's coefficient allowed separation of the 29 clones into three clusters. Genetic relatedness between the clones was found to be at 70% level. Random Amplified Polymorphic DNA (RAPD) analysis of DNA of ten short-listed (on the basis of field performance for drought tolerance) clones using 11 primers, revealed 180 PCR products of which 131 were polymorphic bands. Activity of drought-specific superoxide dismutase (SOD) and ascorbate peroxidase (APX) isozymes was found to be appreciably high in RR17/144, CP1, TV26 and AV2. Regression analysis using peak areas (from scans of stained activity-gel preparation) of Cu-Zn SOD and APX II as dependent variables and RAPD band scores as independent variable revealed that OPAH02 primed DNA band at 1400 bp was associated with high activity of the drought tolerance-specific isozymes. Using Fisher's exact test (F-test), this association was found to be at 99.9% confidence level.