M. S.

This study was conducted to evaluate the effect of leaflet shape on yield and other characters of soybeans, <i>Glycine max.</i> (L.) Merrill, by using narrow and broad leaflet isolines. The breeding procedure employed developed pairs of isolines whose genetic backgrounds were a random recombination of the narrow and broad leaflet genotypes of their parents. Results obtained from 1976 to 1978 indicated that the narrow leaflet isolines on the average are similar to the broad leaflet ones in seed yield. The narrow leaflet isolines were earlier, but the average difference vas no more than 1.7 days. They also were consistently 1.5 to 3.0 cm shorter in all three years. The difference in lodging between leaflet types was always very small. The differences in these agronomic traits, though significant in several instances, do not imply any practical advantage of either leaflet type. Data from six pairs of isolines sampled in 1978 showed that leaflet shape had a significant effect on seed size, but not on seeds per plant, pods per plant, and seeds per pod. Narrow and broad leaflet isolines showed similar oil and protein contents. The narrow leaflet isolines of the same six pairs exhibited less leaf area per plant, less leaf weight per plant, lower leaf:stem ratio, and higher seed:stem ratio than the broad leaflet ones. The difference in specific leaf weight was non-significant. None of these traits was associated with yield per plant. / M. S.