S. Safaei Chaeikar - Tea Research Center, Horticultural Science Research Institute, Agricultural Research, Education and Extension Organization, Lahijan, Iran.
Sh. Roofigari Haghighat - Tea Research Center, Horticultural Science Research Institute, Agricultural Research, Education and Extension Organization, Lahijan, Iran.
S. Marzvan - University of Zanjan, Zanjan, Iran.
R. Azadi - Tea Research Center, Horticultural Science Research Institute, Agricultural Research, Education and Extension Organization, Lahijan, Iran.

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 ۵۰ days. The effects of drought stress were measured by studying growth and morphological (shoot number, shoot length, shoot fresh weight, length of ۵th leaf, width of ۵th leaf, green leaf yield), physiological (relative water content), biochemical (proline and total sugar content), and chemical (polyphenol) attributes after ۵۰ 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 ۲۷۶, ۱۰۰, and ۲۸۵ formed drought-tolerant group. These tea clones can be used in the national tea breeding programs for improvement of drought tolerance.

Tea, Antioxidant activity, Proline, Polyphenol, relative water content, Total sugar, Water stress