Variations of fatty acids levels in young shoots of clonal tea with location of production and nitrogenous fertilizer rates in the Kenya highlands

Abstract

Tea leaves contain unsaturated fatty acids, key precursors of volatile compounds contributing to tea aroma quality. Tea is cultivated in areas with diverse environmental conditions. Nitrogenous fertilizers influence tea yields and quality. A previous single site study demonstrated that increasing nitrogenous fertilizer rates raised fatty acid levels. However it is not known if the magnitudes and patterns of the responses are replicated in different locations due to variations in growth factors. Nonetheless, there is a single fertilizer rate recommendation in all tea growing locations in Kenya. This study assessed possible variations in patterns and magnitudes of fatty acids in a single cultivar grown under similar nitrogenous fertilizer rates in different locations. Trials were conducted in five locations using clone BBK 35, receiving varying nitrogenous fertilizer rates. Fatty acids in two leaves and a bud were quantified as methyl esters. The levels varied (P≤ 0.05) with locations and increased (P≤ 0.05) with nitrogenous fertilizer rates. The rates of increase differed with locations leading to significant (P≤ 0.05) interaction effects. Thus, similar fertilizer rates in different locations result in different fatty acid levels, explaining differences in tea aroma quality from different locations even with the same agronomic inputs. The results demonstrate the need to develop region-specific agronomic inputs for the production of same tea quality