RESPONSE OF TOMATO YIELD AND POST HARVEST LIFE TO POTASH LEVELS

The present study was undertaken to develop potassium management recommendations that maximize yield and post harvest quality of tomato. Studies were conducted at Faculty of Agriculture, Gomal University, Dera Ismail Khan, KPK, Pakistan during 2008-2009. A pot experiment was designed, which included six potassium fertilizer treatments (75, 150, 225, 300, 375, 450 Kg K2O ha^-1) with basal doses of N and P (100 Kg and 80 Kg ha^-1, respectively). Pots treated with N and P alone were kept as control treatment. Each treatment was replicated 4 times and treatments were arranged in Complete Randomized Design. All potassium treatments significantly increased yield characteristics as well as post harvest quality of tomato fruit compared with untreated one (control). However, Treatment (NP+450 K2O Kg ha^-1) surpassed all the other treatments in term of yield parameters. Potassium application significantly increased number of flowers plant^-1, fruit setting rate, number of truss plant-1, fruits plant^-1 and yield ha^-1. Moreover, increased potassium levels also had positive effect on post harvest life attributes of tomato fruit. In addition, the Shelf life, quality of general appearance and taste were significantly influenced as potassium levels increased to 375 kg K2O ha^-1 but decreased at 450 Kg K2O ha^-1. On the other hand, while increased potassium levels decreased all the undesired parameters, wilting and drying of calyx, physiological weight loss %, and % non marketable yield .Therefore, when potassium was applied @ 450 Kg K2O ha^-1 it increased the yield had decreased the adverse effect on marketable yield, wilting and drying of calyx and weight retention of tomato fruit. In conclusion 375-400 Kg K2O ha^-1 is recommended as it produced better quality tomatoes with longer postharvest life.