This study aimed to evaluate the performance of conventional and Roundup ReadyTM soybean when subjected to different plant stands. Three trials were conducted in the municipality of Jari-RS, the first in November 2004, the second in November 2005 and the last in January 2006 (after the recommended time). The conventional cultivars 'CEP/CD 41', 'CD 201', 'Fundacep 39', 'CD 205' and the Roundup ReadyTM 'AL72', 'NK Mágica 7.3 RR' and 'A 6001 RG' were sown at densities of 250, 400 and 550 thousand plants ha-1. The experiments followed a randomized block design with twenty one treatments and four replications. The treatments were arranged in a split plot represented by cultivars in the plots, and the populations of plants in the subplots. Grain yield and the yield components pods per plant and m-2, 100-seed weight and number of seeds per plant were evaluated. The performance of conventional and Roundup ReadyTM cultivars differed with the plant stand. Under severe water stress the increase in plant stand did not affect yield. Only cultivar 'A 6001 RG' showed stable performance under different plant stands, indicating a greater plasticity of this cultivar. The number of pods per plant was reduced with the increasing the number of plants per area. The largest yields were achieved with the largest number of pods m-2. The highest 100-seed weight was found for the largest plant stand. The number of seeds per pod decreased with increasing plant stand. The most favorable growing conditions tend to increase pods m-2, 100-seed weight and number of seeds per pod.
Glycine max L. (Merrill); seed density; transgenic soybeans; yield; yield components
