Effective Population Size for the Soybean Improvement Program in Maturity Groups 00 to IV¹

Abstract

The past 50 years of soybean ( Glycine max L. Merr.) cultivar development in the midwestern United States and Canada can be considered a program of recurrent selection now in its third or fourth cycle. The effective number (N) of lines recombined in each cycle was estimated by determining coefficients of parentage of 27 cultivars released between 1976 and 1980. The relatively low N value (11 to 15) indicated that soybean breeders have made progress at the expense of the loss of a substantial portion of the genetic variation originally available.