Common bean elite lines cultivated under nitrogen fertilization and inoculation with Rhizobium tropici

Abstract

More efficient strains of Rhizobium have been selected for use in common bean. However, little effort was made with lines selection. The main goals of this research were to verify the presence of interaction involving common bean elite lines utilizing Nitrogen fertilization and Rhizobium inoculation for grain yield and to identify lines with superior yields utilizing biological nitrogen fixation. Eight field trials were conducted at four location- years in Brazilian savanna, using randomized complete blocks design with three replications. Each trial was composed of 17 “carioca” elite lines. Every two tests in each location were planted side by side, one with mineral nitrogen fertilization (90kg) and the other one with inoculation with Rhizobium tropici SEMIA 4080 strain. Elite lines interaction with nitrogen fertilization/inoculation was not important, so, it is possible to select lines for utilization in both growing systems. In some locations-years, interaction between lines and Rhizobium inoculation was most affected by environment conditions, causing modification in lines classification according to the type of nitrogen supplying used. In general, the lines presented higher yields when fertilized with mineral nitrogen as compared with inoculation. The cultivar ‘BRS Pontal’ presented high and similar yields under both systems of nitrogen supply.