Performance of some Promising Genotypes of Soybean Under Different Planting Dates Using Biplots Analysis

Soybean yield is affected by planting dates and there are significant efficiency losses when planting are done outward a relatively restricted period. Genotypes and environment are major contributing factor of plant phenotype. Economically important quantitative traits include agronomic characteristics. Four separate experiments are carried out in each season at the experimental farm of Sakha Research Station, Kafr El-Sheikh during 2010 and 2011seasons. Seed yield of six soybeans cultivars i.e. Giza 21, Giza 22, Giza 111, H2L12, H30 and H32 examined at four different sowing dates i.e. 20th April, 5th May, of 20th May and 5th June of their effect on seed yield, and yield components. Highest number of branches/plant, number of pods/plant, 100 seed weight (g), and seed yield. Soybean cultivars showed high difference in seed yield and its component, Giza 21 exhibited maximum number of pods/plant, 100 seed yield, and seed yield. H32 cultivar contributed highest number of branches/plant. Through genotypes and genotypes x environment biplots of regression model analysis results, the performance of a cultivar at different environments was compared, the performance of six cultivars at different environments (planting dates) were compared. The results indicated that sown on 5th May increased seed yield/ha by 19.7% compared with sown on 5th June and increased seed yield by 17.9% compared with sown on 20th April, and increased seed yield by 10.3% compared with sown on 20th May. It could be noticed that Giza 21 cultivar exceeded H32 line by 16.63%, H30 line by 14.6%, Giza 22 cultivar by 13.7%, H2L12 line by 6.5% and Giza 111 by 5.3% in seed yield/ha. Highest yielding cultivars at the different mega environments were identified, and ideal cultivars and test planting date was identified. It could be suggested that soybean genotypes of Giza 21 and Giza 111 are the most promising for planting date 5th May and recorded concentrated seed yield/ha