Genetic Improvement in Yield of Soybeans1

Abstract

Average soybean (Glycine max (L.) Merr.) yields have increased considerably due to changes in cultivars and cultural practices. To evaluate the genetic improvement, yields, lodging, and plant height of 21 cultivars were determined in 3 years. Most of these cultivars were involved in essentially two cycles of recurrent selection. Yield increases were 26 and 16% for the first and second cycles of selection, respectively, while lodging decreased 21 and 20%. Plant height increased slightly.