Soybean may be used as a relay crop in rotation systems. Such systems yield high physiological quality seeds and determine a short storage period until the next crop. The effect of plant density of soybean cultivars sown in the winter season in Selvíria, SP, Brazil, was studied in relation to plant height, first legume height, seed yield and seed physiological quality. Trials were set up in a randomized block design (n=4), comprising seven soybean cultivars (IAC-16, IAC-Foscarin 31, FT-2, IAC-17, IAC-8, Doko and FT-Cristalina) sown at three plant densities (300,000/ha, 400,000/ha and 500,000/ha). There was a sharp decrease in the number of days to maturity (R8 stage) mainly for the late cultivars. The photoperiod in the winter season is short, mainly between flowering and maturation. The IAC-8 cultivar presented less sensitivity to the photoperiod, spending the same number of days to maturity (R8 stage) as for the late cultivars, and the had the best agronomic characteristics for the winter season. It is not recommended to store seeds under controlled conditions, mainly when germination values are close to the acceptable value (80%).
plant population; cultivars; first legume height; seed storage