Physiological quality of conventional soybean cultivars of seeds as a function of pod position in plant canopy
Soybean cultivars have different growth habits, and the cultivation of those of indeterminate habit has increased significantly in Brazil. Thus, the aim of this study was to evaluate the physiological quality of soybean seeds produced in two harvests, from cultivars with different growth habits and ripening cycles, harvested in different canopy thirds of the plant in the canopy. The seeds were produced in Ipameri, Goiás –Brazil, in two crop harvests, 2014/15 and 2015/16. A completely randomized design was used in a 4x3 factorial scheme with four replications. The treatments consisted of four soybean cultivars with different growth habits and ripening cycles (BRS 6780, BRS 6980, BRS 7980 and BRS 8381), harvested in three positions of the plant canopy (upper, middle and lower). Germination, first count, accelerated aging and electrical conductivity tests were performed. It was observed that the physiological quality of genetic materials studied was influenced by the variable environmental conditions. Soybean cultivars the early cycles produced seeds of superior physiological quality, regardless of plant growth habit. Seeds of soybean cultivars of indeterminate and determined growth habits and earlier cycle, harvested from the upper and middle thirds of the plant, are of better quality. Finally, cultivars with semi-determined and determined habits and late cycles will produce lower quality batches of seeds, regardless of which third of the plant they were harvested.