GENOTYPIC SPECIFICITY OF SOYBEAN [GLYCINE MAX (L) MERR.] UNDER CONDITIONS OF FOLIAR FERTILIZATION

Knowledge of genetic traits that affect yield and chemical composition of soybean grain is vital for the organization of an effective soybean breeding program. Two-year trials (2009-2010) were carried out at the Rimski Sancevi Experiment Field of the Institute of Field and Vegetable Crops in three replications. We assessed the impact of foliar fertilization with a complex liquid fertilizer that combined macroelements (N, P, K - 12:4:6, respectively) and microelements (Fe, Mn, Cu, B, Zn) on yield and grain chemical compositions of NS soybean cultivars of different maturity groups. The following traits were monitored: 1000-grain weight (g), soybean grain yield (kg/ha), and total protein and oil contents and protein and oil yield in soybean grain. All traits varied significantly depending on variety and year. On average, all cultivars had higher yield and 1000-grain weight in the variant with foliar fertilization than in the control. The highest yield in the control variant was achieved by the cultivar Victoria (5273 kg ha(-1)) in 2009, while the highest yield in the variant with foliar fertilization was achieved by the cultivar Tea (5333 kg ha(-1)) in 2010. The average weight of 1000 grains was significantly higher in 2010 (161.2 g) than in 2009 (132.4 g). The lowest average 1000-grain weight was registered for the cultivar Galina (140 g). The cultivar Victoria had the highest protein content in the control variant, while the cultivar Tea had the highest oil content (21.73%). In the variant of foliar fertilization, the cultivar Tea had significantly higher contents of proteins and oil than the other tested varieties. The values of the coefficient of correlation between the studied traits in the variant of foliar fertilization were similar to the values in the control variant. The oil content was significantly and negatively correlated with 1000-grain weight (r=-0.86**, r=-0.80**) and negatively correlated with protein content in soybean (r=-0.42, r=-0.04) in both the control variant and the variant with foliar fertilization. The yield was negatively correlated with protein content (r=-0.36, r=-0.05) in the control variant and the variant with foliar fertilization. The obtained results indicate that the yield, protein and oil content in soybean is a cultivar characteristic, but it is also strongly affected by the environment and affected by the foliar fertilization.