Responses of Young Tea (Camellia Sinensis) Clones to Drought and Temperature. I.Yield and Yield Distribution

摘要

The yield responses to drought and temperature of six contrasting tea cloneswere studied in a line-source irrigation experiment in Southern Tanzania. Theselected clones, all commercially and/or scientifically important in easternAfrica, embrace a range of morphological and physiological types. The busheswere planted in August 1988 and differential drought treatments were imposed for16 and 13 weeks towards the end of the dry seasons in 1990 and 1991respectively. The resulting soil water deficits were successfully simulatedusing a water balance model. Under well-watered conditions Clone S15/10 (fromKenya) gave the highest yield of dry tea reaching 5600 kg ha-1 in the fourthyear after planting (1991/92) compared to 3640-4420 kg ha-1 for the other fiveclones. During the cool season Clone SFS150 (from Malawi) yielded more thanClones 1, 207, 6/8 and K35. Although annual yields decreased curvi-linearly asthe maximum soil water deficit increased, single values for the droughtsensitivity of each clone could be derived by using stress time as an index ofdrought. On this basis Clones S15/10 and 207 were identified as being the mostsensitive to drought; Clones SFS150 and 1 were drought resistant. The reasonsfor these differences in yield responses and the importance of determiningdrought sensitivity over an appropriate time period are discussed.