Soybean Yield of Grain, Oil, and Protein as a Function of Cultivar, Field Environments and Water Restriction in Controlled Environment in Southern Brazil

The interaction between cultivar and environment on soybean grain composition has few information under subtropical production systems, especially with modern cultivars. The objective was to evaluate soybean yield performance and grain composition in terms of oil and protein of two cultivars (BMX Apolo RR and TMG 7262 RR) in (i) a field experiment at four locations, and (ii) in a greenhouse experiment under three water availability treatments: control, water restriction at grain filling and water restriction during the whole cycle. Both experiments carried out during two growing seasons in southern Brazil. The average yield in the field experiments was 5912 kg ha −1 , which characterizes as high yield environments. The higher average temperature increased grain oil concentration only in TMG 7262. In general, the cultivar BMX Apolo presented a higher grain protein concentration whereas TMG 7262 presented higher grain oil concentration, except in one environment. Thus, oil and protein concentration varied more between cultivars than between environments. The water restriction at grain filling had more effect in terms of grain yield, whereas the water restriction at whole cycle increased grain protein concentration only in BMX Apolo. Cultivar TMG 7262 presented the highest oil yield in most environments, whereas cultivar BMX Apolo presented the highest protein yield in most environments, which shows that the choice of cultivar must consider the purpose of the grain quality that is sought to be produced. There is room for improvement in oil and protein yield performance with the proper arrangement of soybean cultivar and production environment.