RESPONSE OF SOYBEAN (Glycine max L. (Merr) VARIETIES TO INOCULATION IN THE SOUTHERN GUINEA SAVANNA OF NIGERIA

Abstract

Yield of soybean in the soils of Nigeria Savanna are often low because of inadequate effective rhizobia in the soil. The use of rhizobia inoculants may benefit the soybean plant through improved or enhanced Biological Nitrogen Fixation. The objective of this study is to determine the response of five varieties of soybean to rhizobia inoculation. A field experiment was carried out during the, 2011 and 2012 season at the Teaching and Research farm of the Federal University of Technology Gidan Kwano Minna. The experiment was laid out in a 3 x 5 factorial fitted to a randomized complete block design and replicated three times. The treatments consisted of nutrient sources and varieties (Control, Inoculated and Nitrogen in form of urea at 100 kg N/ha) and five promiscuous soybean varieties (TGX 1904-6F, TGX 1835-10E, TGX 1945-1F, TGX 1951-3F, TGX 1448-2E). The result of the experiment showed that the interaction between nitrogen sources and varieties had no significant effect on yield and yield components except for pod load and pod weight in 2011 planting season. The N-supplied treatments had similar yield and yield components as the control suggesting the effectiveness of the indigenous rhizobial population. Response to inoculation was only significant for nodule number. The main effect of varieties significantly affected plant height, pod weight, biomass dry weight and grain yield in 2011 while significantly affecting percent emergence, pod load, 100 seed weight and haulm yield in both seasons. The highest grain yield was produced by TGx 1448-2E and TGx 1951-3F suggesting the suitability of these two varieties for cultivation in the Southern Guinea savanna of Nigeria.