Comparison of Protein and Oil Concentration of Soybean (Glycine max. Merr.) Cultivars Under Main and Second Cropping Systems

Abstract

Maturity group (MG) II, III and IV soybean cultivars are shown the best adaptations in the conditions of southern Turkey. These cultivars generally can be sown from April (as a main crop) to July (as a second crop). The study was conducted to determine the effect of early and late planting dates on oil and protein concentration of soybean cultivars from different maturity groups in Diyarbakir conditions, during 2003 and 2004. It has been found that oil and protein concentrations were not affected significantly by planting dates. However, significant differences were observed among cultivars for protein concentration but not for oil concentration, thus a greater performance was seen in the cultivars from MG IV. Planting date x cultivar was significant for protein concentration and the protein concentration was found to be higher for Stressland (MG IV), Cisne (MG IV) and Macon (MG III) in the early planting (387, 383 and 381 g kg^-1, respectively). Similarly, Stressland has also the highest protein concentration in the late planting (390 g kg^-1), whereas Amsoy 71 (MG II) has the lowest protein concentration in both planting dates.