Efectividad del tratamiento fitohormónico para el almacenaje de papas en las zonas altas en los Andes

Abstract

Chemical inhibition of sprouting of potatoes in storage has been studied intensively in North America and Europe but it has not been a substitute for the need of relatively low temperatures during storage. In the Andean Highlands, where the potato is a daily staple food, the prevailing average temperatures of 10° to 13° C, have indicated the possibility of using inhibitors without special storage structures for artificial refrigeration. This paper presents the results of such a study, made at Junin in the Mantaro Valley of Peru, at an elevation of 3316 meters, with average temperature of 11.8° C (maximum 19.9° C, minimum 4.89° C). The Casablanca variety, which usually sprouts in 3 months, was used for the treatments which consisted of three dosages of methyl ester of naphthalene-acetic acid (MENA): 0.3%, 0.6%, 1.0% and an untreated check. The chemical was mixed with fine soil (instead of talcum to allow for a more natural final appearance) and it was then used at the rate of 1 kilogram of the mixture to 100 kilos of potatoes. This resulted in concentrations of 30, 60 and 100 mg. of MENA per kilo of tubers. Each treated lot consisted of one ton of potatoes placed in paper lined wooden bins in successive layers, separated by sheets of newspaper to prevent the sifting down of the MENA—impregnated soil. At the end of the 5 month storage period, by mid December 1956, data obtained presented in several tables, indicate that the 1.0% treatment resulted in a very small amount of sprouting and weight loss. This concentration also gave satisfactory results in cooking tests, vitamin C and sugar content, palatability and appearance. The lower concentrations did not prove to be as effective as the 1.0% level. In a limited marketing test, the potatoes from the best treatment were rapidly sold in Lima at retail, at the same price as potatoes produced more recently on the coast and held under refrigeration. In Lima the retail price of potatoes had gone up 150% (from S/.0.80 to S/.2.00 per kilo) during the period of the experiment. The cost of the treatment was only 0.06 Soles per kilo of potatoes, based on a price of US $15.00 per lb of the pure chemical. The low cost and ease by which any farmer may use this method are discussed. The authors suggest that other known inhibitors such as cloropropham—[...], N—carbamate and maleic hydrazide should find wide possibilities for use in the Andean potato regions, but warn that tubers to be treated, as in the present study, should not be used for planting stock.