PHYSICAL METHODS OF PRE-PLANTING AND POSTHARVEST TREATMENT OF POTATO: A REVIEW

Potato is an important staple food crop. Potato tubers require proper treatment before planting and after harvest to produce high yields and avoid storage losses. Among different techniques of potato treatment physical methods are of special interest: thermal treatment using hot water and steam, ultraviolet (including continuous-wave UV using pulsed Xe-lamps) and gamma-irradiation, treatment with magnetic and electromagnetic fields (including microwaves). The majority of physical methods is environmentally friendly and can be applied without special registration and in the developing countries. In the present paper, for the first time, the scientific papers on physical methods of potato treatment for the last 35 years are comprehensively reviewed. The review demonstrates that such an approach is perspective both for pre-planting and postharvest treatment of potato. Physical treatment affects biochemical, cellular and physiological status of potato. Methods of physical treatment enable to control phytopathogens, and some methods (ultraviolet and gamma-radiation) even are capable of improving immunity of plants. The main traits of potato tubers that can be influenced by physical treatment are sprouting (stimulation or inhibition), susceptibility to rot and black leg diseases, and starch, reducing sugars and ascorbic acid contents. The tuber response to physical treatment depends on dosage and date of treatment, duration and temperature of storage, agricultural technology and cultivar. Low doses of treatment may be inefficient while too high dosage may result in cell deterioration or death and poor immunity, and eventually to disease development. Too early treatment may damage a tuber since it should pass through suberization (wound healing) after harvest; too late treatment requires higher doses. The proper adjustment of treatment is necessary for cultivar and individual storage conditions.