Abstract:The results of introducing summer soybean germplasm from Shandong Province into spring soybean breeding program in the Northeast of China were reported in this paper. In the breeding program, selections were made for yield components, especially pods per plant and pods per nod, to improye the selection efficiency of yield. Tree types of crosses were made as the following:1. Spring×Summer, the objective was to obtain breeding material with high yield potentials; 2. High yield progenies with homogeneous major ecological characters of the first cross type×local adaptive cultivars or breeding lines, the purpose was to develop varieties or lines with high productivity; 3. Breeding lines derived from the second cross type × local adaptive varieties or lines, the objective was to develop high yield varieties.
The results indicated that germplasms with high yield potentials could be obtained from the first type of crosses. High yield, good quality, and disease resistant cultivars with exlent agronomical characters could be developed from the second and third types of crosses. Since the breeding program can not only maintain genetic variability, but co-ordinate the productivity and adaptability on a high level, it provided an effective new way for high yield soybean breeding.