Fig. 1. Mean seed yield over plant populations derived from a) 42 cultivars (Exp. 1), and b) seven soybean cultivars (Exp. 2) released from 1934 to 1993, from trials grown at Ottawa, ON. LSD 0.05 for Exp. 1 in 1998 on clay loam and sandy loam are 58 and 85 and for 1999 on clay loam and sandy loam are 82 and 111; and for Exp. 2 for 1999 on clay loam and sandy loam are 207 and 214 and for 2000 on clay loam and sandy loam are 225 and 195, respectively.