Seed Inoculation with Pseudomonas fluorescens Promotes Growth, Yield and Reduces Nitrogen Application in Maize
Itacir Elói Sandini, Fabiano Pacentchuk, Mariangela Hungría, Marco Antônio Nogueira, Sonia Purin da Cruz, André Shigueyoshi Nakatani, Rua Simeão Camargo Varela de Sá
Abstract
<ns2:p>Plant growth-promoting bacteria (PGPB) improve plant nutrition, growth, resistance to stresses and yield, having long been employed to inoculate crops worldwide. Pseudomonas fluorescens exerts acknowledged PGPB activity towards several crops, inducing systemic resistance to diseases, plant tolerance to adverse conditions, and promote yield. In present study, inoculation of maize seeds with P. fluorescens was compared with Azospirillum brasilense, a commercial PGPB inoculant, with a concomitant 25% reduction in the amounts of N fertilizer recommended. Six field experiments were carried out in distinct geographic regions of Brazil, where maize is grown under standard or high technological level, with different expectations regarding grain yield. The results demonstrated that P. fluorescens promoted plant growth and yield at both levels, increasing plant biomass accumulation by 24 and 20%, relative to the non-inoculated control, at standard or high levels, respectively. The grain yield increased by 29 and 31%, relative to the non-inoculated control, under standard and high levels of technology, respectively. Under both situation, plant growth and grain yield improved by P. fluorescens was equivalent to the application of 100% of the recommended N fertilizer, even when the amount of N fertilizer applied to the crop was reduced by 25%, without compromising yield. For the first time, the successful utilization of P. fluorescens for growth-promotion of maize, in Brazil, with a concomitant reduction of the need for N fertilizer, resulting in profitable yields with reduced costs and environmental impacts was reported.</ns2:p>