Nine soybean varieties representing most of known maturity
groups were evaluated at four planting dates i.e 1-t. 15th, May, 1and
151!i_June. Seed yield data were subjected to phenotypic stability
analysis according to the procedure proposed by Eberhart and Russell
(1966). The results revealed that the two varieties (Williams 82 and
Clark) were more stable than the Crawford and Columbus under the
environments study. The unstable varieties i.e. (Crawford and
Columbus) seemed to have high seed yields above grand mean. These
varieties, however, could be over looked because their high potential
was limited to particular environments. Crawford and Columbus varieties
gave the highest yield when sowing in 15th May.