The Effect of Various Species of Bradyrhizobium japonicum on Grain Yield, Nodulation and N2-Fixation in Different Soybean Genotypes in the Harran Plain of the GAP Region

The aim of this research was to evaluate the most effective N2-fixing Bradyrhizobium japonicum isolates under the field condition of the GAP region (Plain of Harran) for nodulation, N2-fixation and yield of soybean. In this study, for the second crop various genotype of soybean such as isolates (So11, So56, 110, 1755, 1756, 1809, 30131, ON1, ON2 and ON3) in 1993 and 1994 and (So11, 1756, 1809 and ON3) isolates in 1995 were inoculated determined the nodule formation, N-content of nodule, shoot, total N uptake by root and seed, dry matter formation of soybean and seed yield. During the 1993 and 1994 under the second crop condition, since soil temperature was so high and the soil moisture content which is usually low, the nodulation has not been formed. But, in 1995 in order to found out the effect of seasonal change on sowing time, soybean has been sowed as a first crop. Thus, as a result of first crop the nodulation was formed. The results of study show that inoculation of Bradyrhizobium japonicum positively influenced the N2-fixation, seed yield and dry matter yield. It has been observed that the isolate of ON3 which has isolated from Çukurova region did not have any nodule. The isolate of 1809 is the one of them which has performances the highest response than other isolates for both of soybean genotype. The isolate of So11 and 1756 shows the similar response in term of several plant parameters. Compression of soybean genotypes shows that S4240 genotype was produce nodulation, N2-fixation and yield than the genotype of Sa88