Determination of the effects of shading on some agronomical and morphological traits of tea plants (Camellia sinensis (L.) Kuntze)

This study was conducted in Rize province in 2024 according to a randomized block trial design with 3 replications. In the study, shading nets were used at different rates (Control, 35%, 55% and 75%) and some agronomical and morphological characteristics of tea (Camellia sinensis (L.) Kuntze) plants were examined in the first shoot period. Measurements made on harvested plants included shoot length (cm), number of leaves per shoot (unit), leaf length (cm), leaf width (cm), leaf color, fresh leaf yield (g/m2), dry matter content (%), total polyphenol (%) and caffeine content (%). As a result of the study, it was determined that tea shoot length and tea dry matter ratio were not affected by shading; however, all other examined traits were affected statistically significantly (P<0.01) depending on the shading rate. The highest values in terms of leaf length, leaf width and leaf color were obtained in the control and 35% shading ratios, while the highest number of leaves on the shoot was obtained in the 75% shading ratio. As the shading ratio increased, the number of leaves per shoot also increased, while the fresh leaf yield tended to decrease. At 75% shading rate, total polyphenol and caffeine levels obtained from tea leaves were at the highest level, and decreasing the shading rate led to a decrease in the values obtained from these two quality elements.