Intergenotypic competition effects on soybean -Glycine max (L.) Merrill - cultivar blends was evaluated in an experiment carried out along the 1989/90 crop season, in Capão do Leão county, RS. Five cultivars, IAS 5, Ivorá, Bragg, Ivaí and BR 8-Pelotas in pure stand and the blends of Bragg with every cultivar, in the proportions of 20, 35, 50, 65 and 80%, were alocated to a partially balanced 5 x 5 lattice design with four repetitions. Intergenotypic competition was quantified by percent vanation 1 (PM - PEP)/PEP, where PM stands for the vanable mean in the blend and PEP for the variable mean in pure stand. The blends yielded, in average, 3.8 % more than the mean yield of the components in pure stand. Two blends, IAS 5 + Bragg and BR 8-Pelotas + Bragg had an increment in yield, for the proportions studied. It was concluded that, the intergenotypic competition may be used in soybean breedmg programs to obtain cultivar blends with superior yield and performance. Differential responses to intergenotypic competition were observed in distinct blends and proportions; and proportion and contrasting charactenstics between the cultivars as branchung, height, maturity and flowering should be considered for the formation of superior blends.
intergenotypic competition; soybean; Glycine max
