Productivity evaluation of soybean varieties inoculated with Bradyrhizobiumjaponicum in no-tillage system under Urochloaruziziensis straw

Soybean (Glycine max (L.) Merril) has been shown great potential productivity in Brazil due to its cultivation conditions and desirable traits of soil and climate. Much of the culture's success is due to the quality and versatility of the genetic material used, especially its phenotypic plasticity. In the western region of the state of São Paulo, its cultivation has been brought benefits, derived in part by the main cultivation system used, no-tillage system, which reduces the use of phytosanitary products that harm the environment and the use of straw from the previous crop. In this work, we aimed to evaluate the agronomic traits of soybean cultivars with different doses of the inoculant Bradyrhizobium japonicum, implanted in no-tillage system, aiming to identify those cultivars most adapted to the cultivation conditions. The experiment was conducted at FCAT - Dracena, under a randomized block design in a 3x3 factorial scheme, in which the five cultivars were evaluated: NS 7709 IPRO; NS 6700 IPRO; NS 6906 IPRO; NS 6601 IPRO; e Monsoy – M6210 IPRO. The following traits were evaluated: plant height (Ph), first pod height (Fph), total pods (Tp), number of stems (Ns) and grain yield (Gy). For the inoculant factor we evaluated: control (zero dose), recommended dose and six times the recommended dose. It was performed Analysis of variance and Tukey test to compare the mean performance of cultivars for those that showed significance in ANOVA. The cultivar NS 7709 IPRO showed adequate grain yield estimate (6,044 kg ha-1), standing out numerically in four of the five evaluated traits. It could be the recommended cultivar in west region of São Paulo State – Brazil, where the experiment was conducted. The use of inoculant in doses above the recommended had no effect on the analyzed variables or even obtained results lower than the recommended dose.