ABSTRACT

Sustainable potato production requires continuous provision of high-quality seed tubers. However, obtaining adequate high quality (healthy medium-sized) potato seed is the major challenge in potato seed tuber production. Nutrient management particularly Phosphorous (P) and potassium (K) are vital for the regulation of the yield and tuber quality attributes of the potatoes. This study was conducted to test and determine the economically optimum amount of P, K, and PK required for higher seed tuber yield and quality of three potato varieties. The experiment had four levels (control, a quarter (8.5, 85kg), half (17, 170kg), and complete dosages (34, 340kg)) of P and K fertilizers recommended for ware potatoes as the factorial main plot factor and the three potato varieties as subplot factor in a split-plot design with three replications. Results showed the absence of statistically significant interaction effects (p>0.05) of variety by fertility management. However, cultivar, P, K, and combined application of P and K affected some growth, yield, and quality characteristics of the varieties. Only P application remarkably affected seed tuber yield and the economic benefit of the varieties. Among the tested fertilizer levels, a quarter of the recommended P for ware potato gave maximum standard seed tuber yield (20.51t) equivalent to the recommended P level (23.51t). It has enhanced the economic benefit of medium-size and total seed tuber by 385 and 362%, respectively. The result indicated that a quarter of the P fertilizer required for ware potato production is optimal for economically feasible seed tuber production.