Evaluation of nutrient solution phosphorus concentration on potato plantlet tuber production under greenhouse conditions1

Abstract

Abstract Phosphorus fertilizer management of greenhouse grown micropropagated potato plantlets has been based on field research. Differences in growing conditions, potting media and the planting material itself may make the field research data base unacceptable in a greenhouse environment. This study was conducted to determine the optimum nutrient solution phosphorus (P) concentration for maximum growth and yield of micropropagated potato plantlets grown under greenhouse conditions. Nutrient solution P concentrations ranging from 0 to 55 μg P/ml were evaluated. Each nutrient solution P concentration was applied weekly to micropropagated potato plantlets that were grown in 80% vermiculite‐20% sand potting medium. Results indicate that P concentrations between 10 and 35 μg P/ml are optimum for potato plantlet tuber production. This P concentration range maximizes vegetative weight, total tuber weight and number of tubers produced per micropropagated potato plantlet. Data further indicated that the potting medium retained and possibly accumulated P from the weekly applied nutrient solution. This enabled the plants, receiving relatively low nutrient solution P concentrations, to extract more P for proper growth and yield with time. To avoid unnecessary nutrient costs, the 15 μg P/ml nutrient solution concentration is recommended. This P concentration will produce maximum tuber yields and still allow for less than optimum management which may cause P conversion to unavailable forms. Additional studies should be conducted to correlate plant tissue concentration at different growth stages with final tuber yields.