Tuberização de batata-doce em função de épocas de transplantio

Abstract

Sweet potato is a fundamental crop for the food and nutritional security of different populations, and due to its relative tolerance to abiotic stresses, it is considered a key crop for facing the challenges imposed by the current scenario of climate change. The main fraction of interest in the crop are the tuberous roots, so that tuberization constitutes the main physiological process of the same. However, tuberization, and consequently yield, may be affected by unfavorable environmental conditions resulting from cultivation at inappropriate times. Thus, the present study aimed to evaluate the effects of transplanting time on tuberization and yield of sweet potato under edaphoclimatic conditions in the Central-Eastern Mesoregion of Paraná, Brazil. For this purpose, using accession BD-8, belonging to the sweet potato collection of the Laboratory of Agricultural Mechanization of the State University of Ponta Grossa (Lama/UEPG), an experiment was carried out under field conditions, at Fazenda Escola Capão da Onça (25 °05'28'' S, 50°03'40'' W, Cfb, 900 m). The experimental design was randomized blocks, with unbalanced replications, and the treatments consisted of five transplanting times. For each season, collections were carried out at the beginning of the crop's development cycle, in order to estimate the tuber initiation (IT), and final harvest, to determine the shoot and root yields. The thermal sum, water balance and radiation were also obtained for each season, in order to measure their effects on the aforementioned variables. Data were subjected to analysis of variance, and when significant, regression analysis was performed. The time of transplanting influenced the IT, which ranged from 38 to 68 days after transplanting, with the main effects on this variable being exerted by the thermal sum and water balance. In addition, the transplanting time significantly influenced the yield of fresh and dry mass of tuberous roots, which were directly related to the thermal sum. Yield of fresh and dry mass of shoots, and dry matter of roots and shoots were not influenced by transplanting time.