Varietal differences in the adaptability of tea [Camellia sinensis] cultivars to light nitrogen application
2008
Kondo, T.(Shiga-ken. Agricultural Technology Promotion Center, Azuchi (Japan))
To select tea cultivars suitable for cultivation with light nitrogen application in Shiga Prefecture, varietal differences in the adaptability of five major or promising cultivars (Yabukita, Saemidori, Okumidori, Meiryoku, Fushun) were investigated over a five-year survey period. Each cultivar was grown at three annual nitrogen application rates: 80 gN/square m (80N plot), 50 gN/square m (50N plot), and 20 gN/square m (20N plot). Their adaptability to light nitrogen application was determined in terms of yield, component reactivity, and applied nitrogen bioavailability. In all cultivars tested, weight of plucked new shoot and total nitrogen content tended to decrease with the reduction in nitrogen application rate, with weight of plucked new shoot showing a remarkable decreasing tendency. Varietal differences were observed in the reduction in weight of plucked new shoot, with a particularly wide difference found in first crop of tea. Of the five test cultivars, Fushun showed the least reduction in weight of plucked new shoot for first crop of tea in response to the reduction in nitrogen application rate. Fushun also surpassed the other cultivars in terms of weight of plucked new shoot and applied nitrogen bioavailability in the 20N plot. Hence, Fushun was judged to have the highest adaptability to light nitrogen application. Saemidori lost larger weight of plucked new shoot for first crop of tea in the 50N and 20N plots than the other cultivars, and showed considerably lower values of absolute weight of plucked new shoot. Additionally, Saemidori showed lower nitrogen bioavailability than the other cultivars. Saemidori was considered to be poorly adaptable to light nitrogen application.
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