Leaf development and expansion in tea [Camellia sinensis (L.) Kuntze] and their relationships with thermal time: a case study

Abstract

Three field experiments were conducted to study the leaf and shoot expansion in tea [Camellia sinensis (L.) Kuntze] and their relationships with thermal time. The study site was Glen Alpine estate, Badulla, Sri Lanka located at an altitude of 1120 m above mean sea level (AMSL). The first experiment was carried out to develop a mathematical model to predict the area of an individual leaf and total leaf area of a harvestable shoot of widely grown tea cultivars namely, TRI 2025, TRI 2023, TRI 2043 and TRI 3035 in the Uva region. In the second experiment, the number of days required to initiate different leaves of a tea shoot of TRI 2025 was investigated. In the third experiment, the degree-days (thermal time) accumulated for producing different leaves and a harvestable tea shoot with three leaves of tea cultivar TRI 2025 were estimated. Stepwise regression resulted in a model with the product of leaf length and width to estimate the leaf area of a single tea leaf for all the evaluated cultivars with a high precision (R2=0.99). From the bud break, 128.5, 187.5, 234.5, 295.5 ºC days were required to initiate the fish leaf, first normal leaf, second normal leaf and third normal leaf, respectively, of the tea cultivar TRI 2025. A harvestable tea shoot was produced after accumulating 392.5 ºC days by the cultivar TRI 2025.Tropical Agricultural Research Vol. 25 (4): 250-259 (2014)

Keywords

• leaf development, leaf expansion, tea, thermal time