EFFECT OF GIBBERELLIC ACID ON GROWTH, TUBER YIELD AND QUALITY IN POTATOES (Solanum tuberosum L.)

The purpose of this study was to determine the effects of different doses of gibberellic acid (GA(3)) on growth, tuber yield and some tuber quality traits of potato. The experiment was arranged in a split-plot design with three replicates, cultivars Marabel, Alegria and Agria were arranged in the main plots, and GA(3) doses (0, 25, 50 and 100 mg GA(3) L-1) in the sub-plots. Gibberellic acid was applied to leaves by spraying on the 50th day after planting (during flowering). The effects of GA(3) applications on tuber yield of potato cultivars were varied. GA(3) applications resulted in significant decrease on chlorophyll content (SPAD), tuber dry matter and chips quality of potato. But it caused significant increase on number of tubers and tuber yield plant(-1). In 2019 and 2020 years, the highest tuber yield was obtained from Alegria cultivar (62.78 and 50.55 t ha(-1) respectively). Total tuber yield values increased from 52.08 t/ha to 65.14 t ha(-1) in 2019 and from 42.12 t ha(-1) to 53.94 t ha(-1) in 2020 with increasing to 100 mg GA(3) L-1 from 0 mgL(-1). Overall, increasing doses of GA(3) resulted in a reduction in tuber dry matter and starch ratio. The GA(3) applications caused deformations in tuber shape, the deformations increased with increasing GA(3) doses.