Genetic analysis of Glycine max (L.) Merrill in selected sowing time

Glycine max (L) Merrill genotypes (Bossier, Hampton, Improved Pelican and Clark-63) were planted at 15 days interval (1st June, 15th June, 1st July, 15th July, 1st August and 15th August) at Agricultural Research Institute, Tando Jam during summer, 1993. Seed yield and yield components varied significantly (P0.01) due to change in sowing time and genotype. All genotypes yielded more when planted on 1st June, while decreased for each delay in planting beyond 1st June. Among genotypes Bossier yielded more over rest of the genotypes tested. Genetic analysis depicted that plant height and seed yield/plant had greater genetic advance, whereas heritability was more in plant height, seed yield/plant, branches/plant, seed index, effective pod filling period and pods/plant. Correlation of yield was significant and positive with plant height, branches/plant, nodes/plant, pods/plant, seeds/pod, and seed index. Flowering days exhibited significant and positive association with effective pod filling period. Plant height had positive and significant relationship with nodes/plant and pods/plant. The correlation of branches/plant was positive and significant with nodes/plant, seeds/pod and seed index. Nodes/plant displayed positive and significant correlation with pods/plant, while pods/plant depicted positive and significant association with seeds/pod and seed index whereas seeds/pod had positive and significant association with seed index. The path coefficient analysis reveals that pods/plant, plant height and seed index had high positive direct effect on yield. while maturity days displayed high negative direct effect on yield. The multiple regression analysis suggested that pods/plant and seed index contributed significantly towards yield and could be used for future plant breeding programme of soybean.