Responses of some Iranian tea [Camellia sinensis (L.) O. Kuntze] clones to drought stress

Drought is one of the most important environmental stresses affecting tea plantation productivity in tea growing areas. Nine field-grown tea [Camellia sinensis (L.) O. Kuntze] clones in the north of Iran were subjected to drought stress by withholding irrigation for 50 days. The effects of drought stress were measured by studying growth and morphological (shoot number, shoot length, shoot fresh weight, length of 5th leaf, width of 5th leaf, green leaf yield), physiological (relative water content), biochemical (proline and total sugar content), and chemical (polyphenol) attributes after 50 days from the time drought stress was imposed. Drought stress resulted in decrease in growth and morphological characteristics, polyphenol content, and an increase in proline and total sugar concentration, that was attributed to reduction of RWC of leaves. Grouping of clones showed that clones 276, 100, and 285 formed drought-tolerant group. These tea clones can be used in the national tea breeding programs for improvement of drought tolerance.