Responses of Composite Tea to Progressive Drought

An experiment was done on potted grafted tea undera polyethylene tentto quantify the effects of reducing soil moisture content on key physiological factors affecting diurnal and physiological responses of grafted tea clones subjected to varying water levels. The reduced soil moisture content reduced the leaf water potential in all the clones. The diurnal differences in leaf water potential were more pronounced at the 12.5% v/v soil moisture content. Generally, the mean leaf water potential increased with a decline in soil moisture content. Based on this study, the minimum moisture level below which composite tea plants might suffer water stress is below 30% v/v, and the exposure period should be short. Rootstocks identified as being potential for commercialisation are TRFK 57/15, TRFK 8/112, TRFCA SFS 150 and EPK TN 14-3. Among the scions, AHP S15/10 was found to be more susceptible to water stress. Relative water content declined with decrease in soil moisture content (R2 = 0.9915, P<0.001) in all the scions. The total chlorophyll content varied between clones and decreased significantly (P<0.05) with increase in soil moisture content. Rootstocks did not affect the chlorophyll content. Based on the studied parameters of leaf water potentials, relative water content and chlorophyll contents, the rootstocks identified for potential commercialization were TRFK 57/15, TRFK 8/112, TRFCA SFS 150 and EPK TN 14-3.