Qualidade fisiológica e sanitária de sementes de cultivares convencionais de soja em função da posição da vagem no dossel da planta

Abstract

Cultivars of Soybean (Glycine max (L.) Merril) have different growth habits, and the cultivation of those with undetermined growth habit has increased significantly in crops of Brazil. In literature, is found research addressing the components of production in function of the growth of the soybean plant, but on the quality of its seeds little is known. In this sense, the objective of this work was to evaluate the physiological and sanitary quality of soybean seeds produced in two crop seasons, from different cultivars of different growth habits, harvested in different aerial part of the plant. Seed production was carried out in the city of Ipameri, Southeastern region of Goiás, in two crop seasons, 2014/15 and 2015/16, using a completely randomized design, in a 4 x 3 factorial scheme, with four replications. The treatments consisted the combination of seeds from four soybean cultivars with different growth habits and maturation cycles (BRS 6780 - indeterminate growth habit, 95-day cycle, BRS 6980 - indeterminate growth habit, 100-days cycle; BRS 7980 - determined growth habit, 120-day cycle, BRS 8381 - semi-determined growth habit, 130-days cycle), harvested at three positions along the shoot (upper, middle and lower). The analysis of the combined variance of the two harvests was made, and the comparisons were made by the Skott Knott test (p <0.05). Based on the results obtained it is concluded that: the quality standards of the seeds of different genetic materials of soybean, used in the work, were influenced by the crop. Because, there was a differential response between the two harvests on the physiological quality of the harvested seeds. About phytosanitary study, the incidence of pathogens at low levels did not compromise seed quality. Soybean seeds from cultivars of indeterminate growth habits and earlier cycles, BRS 6780 and BRS 6980, produced seeds of higher physiological quality when harvested in the upper and middle strata of the soybean plant. The cultivars with semi-determined and determined habits and later cycles, BRS 7980 and BRS 8381, produced seed of inferior quality, regardless the part of the plant harvested.