The Effect of Paclobutrazol (PBZ) Concentration and Date of Application on Yield and its Component in Potato

In this research, the effect of different concentrations of Paclobutrazol (0, 200, 300, 400mg.L-1) and different application times of paclobutrazol (beginning of tuberization, 10, 20 and 30 days after tuberization) on some qualitative and quantitative traits of ‘Sante’ potato cultivar were investigated. Test was performed in a factorial experiment based on randomized complete blocks design with two factors by 3 replications. Paclobutrazol (Culture commercial suspension with 250gr.L-1 active ingredient of PBZ) was used as foliar spray on potato plants. Conclusion of analysis variances demonstrated that effect of paclobutrazol application time was significant (p≤0.01) on large, small and seed tuber size production. The effect of Paclobutrazol concentration showed significant difference on tuber dry matter percentage, large, small, potato seed tuber, total number, mean weight of tuber and tuber number per plant. Comparison means results showed that use of poclobutrazol with concentrations of 300 and 400mg. L-1 increased amount of tuber in potato plants. As a result, number of total tubers per plant and number of tuber seeds have been increased by 9.8% and 13.2% respectively. Although application of paclobutrazol in these two levels significantly increased mean number of tuber per plant but had no significant effect on total yield comparison with control treatment. By results of this experiment we can conclude that application of paclobutrazol on potato plant will be considerably able to increase percentage of seed tuber size. Consequently, this situation leads to more efficiency of tuber production per area unit in potato seed farms.