Observações sobre degenerescência e comportamento em diferentes épocas de plantio de quatro variedades de batata (Solanum Tuberosum L.)

Abstract

SUMMARY The four potato varieties DELTA-A, HANSA, HYDRA and TON­DRA were tested in lhe dry and in the rainy season of 1971, at Goiânia. lmported certified seed potatoes were used for lhe first plan­ting and the harvested tubers, for lhe second. Ali varieties, except DELTA-A, yielded more in lhe rainy than in the dry season. This difference was found to be caused by the better water supply du­ring the rainy seasOn. There was no significant influence of the season on the production of DELTA-A. HANSA produced in both seasons significantly more in total weight than the other varieties and more marketable potatoes (over 33 mm) in the rainy season. But the large tubers (over 40 mm) harvested in this season became nearly worthless because of the ir.tensive occurrance of internai dark and scattered spots, associated to enlarged lentice Is. HYDRA was the best variety in producing large potatoes, mainly in the dry season. ln both seasons, however, most of the potatoes were lost for the market, due to the strong attack of common scab (Streptomyces scabies). TONDRA showed the greatest difference between yields oi different seasons. Production of marketable tubers increased twice and that of large tubers, almost three times, in tre rainy season. This variety had no trouble similar to that of the other ones and in the rainy season, its yield of Jarge potatoes was not significantly lower than that of HANSA and HYDRA.