Oil and protein content in soybean genotypes developed after 1990

The objective of this work was to investigate whether oil and protein conte nts of soybean cultivars released after 1990 for the State of Rio Grande do Sul, Brazil, differ from the contents found in cultivars in use before tha t year. A study was carried out in 1996/97 involving cultivars recommended at different periods, produced at three sites of that state. Oil content wa s determined by the Soxlet method, and protein content was determined by th e Kjeldahl method. It was found that most cultivars released between 1991 a nd 1996 showed lower protein content and higher oil content than older cult ivars. The use of the Uniao and Industrial cultivars as parents should be o ne of the main reasons to the lower protein content in these cultivars. The change of parents provided a recuperation in the protein content of new li nes up to the level found in the cultivars released before 1990. Phenotypic al correlations indicated that there is a significant negative association between oil and protein contents only.