POTATO MINITUBER PRODUCTION UNDER HYDROPONIC SAND CULTURE

Isolation and use of sterile growing media are two important factors in hydroponicproduction of healthy potato mini-tubers. Sand can be disinfected by solarization,while organic growing media may harbor some pathogenic agents. Underhydroponic condition, number and size of potato tubers are usually controlled bynutritional factors such as nitrogen, phosphorus and pH. The main objective ofpresent study was to find an appropriate combination of N, P and pH (with respectto tuber number) under hydroponic sand culture and to evaluate some physiologicaltraits affected by nutrients and pH. A factorial experiment based on completelyrandomized design with 4 replications was conducted. The experimental factorsincluded N, P and pH. Some morphological and physiological traits including tubernumber, rate of net photosynthesis, concentration of hormones ABA and IAA werestudied. Results showed that higher phosphorus concentration for 10 daysincreased tuber number per plant, but tuberization was not influenced by nitrogeninterruption and intermittent reduction of pH. None of N, P and pH affected totalnitrogen concentration of potato leaf, stem and tuber. Higher phosphorusconcentration increased the level of endogenous ABA and IAA, inducedtuberization and thereby increased net photosynthesis rate of potato plants