<b>Effect of the sowing season and densities in grain yield in soybean, in the South-center region of Tocatins State</b>

Abstract

The objective was to evaluate the influence of different times and seeding rates on seed yield of soybean (Glycine max (L.) Merrill.) in south-central region of Tocantins state. Four experiments were installed in the agricultural year 2008/09. The experimental design was a randomized block design with three replications and 36 treatments. The treatments were arranged in a factorial 3 x 3 x 2 x 2, consisting of three cultivars (M-SOY 9144 RR, M-SOY 8867 RR and P98Y70), three seeding rates (6, 10 and 14 plants per meter), two sowing dates in each of the two municipalities. The first sowing date in Gurupi was December 3 and the second on December 18, 2008. In Palmas, the first time was on November 31 and the second on December 16 2008. The variables measured were plant height and insertion of first pod, hundred seed weight and seed yield. It may be noted that with the delay of sowing date the grain yield decreases, but the increase of seeding rate depends on the cultivar and the variables are dependent on the season and the municipality of planting. The results of Palmas provided the cultivars the highest average yield and the city of Gurupi the best development of soybean plant.