SEASONAL AND CLONAL DIFFERENCES IN SHOOT EXTENSION RATES AND NUMBERS IN TEA (CAMELLIA-SINENSIS)

Shoot extension rates and numbers recorded over an 18 month period in Tanzania from three contrasting clones were analysed to determine variation between and within seasons. Clonal differences in base temperatures for shoot extension ranged from 10.3 to 14.5°C, whilst variability in the response of shoot growth rates to temperature could be ascribed to the shoot selection technique employed. Considerable clonal variation in shoot population densities occurred, with maxima ranging from 200 to 1200 shoots m−2. Total active shoot extension, the product of shoot growth rates and population densities, varied between 4 and 35 m m−2 week−1, shoot numbers being the dominant component. The implications of these results are discussed in terms of shoot measurement techniques, clonal selection criteria, yield modelling and harvesting policies. © 1990, Cambridge University Press. All rights reserved.