Componentes de produção de cultivares de soja submetidos á inoculação, no brejo paraibano

Abstract

The improvement programs in recent years have developed new cultivars with high stability and adaptability, which present desirable agronomic characteristics and high grain yields for the producer regions in the Brazilian territory. In the cultivation of soya (Glycine max L.), the greatest nutritional demand is for nitrogen, which is used for the basic functions of the plant, being metabolised and used for the formation of amino acids, proteins and lipids. Most of this demand is supplied by biological nitrogen fixation (BNF), by the symbiosis of soybean with bacteria of the genus Bradyrhizobium, a process that is responsible for up to 90% of the N2 fixed naturally. The present work aimed to evaluate the effects of seed inoculation on the agronomic and production characteristics of three soybean cultivars in the municipality of Areia-PB. The experiment was conducted in the experimental area of Chã de Jardim, belonging to the Agrarian Sciences Center - CCA of the Federal University of Paraiba - UFPB, Campus II, located in Areia - PB. The statistical design used was randomized block design (RBD) in a factorial scheme 3 x 2 (3 cultivars vs. 2 inoculation methods) with four repetitions, amounting to 24 portions. Sowing was performed manually at the end of April. The inoculant used was BIOMAX® premium composed of Bradrhizobium elkanii bacteria, in liquid format. Harvesting was performed at the end of August when 95% of the pods presented the typical coloration of ripe pods and was done manually. The characteristics evaluated were: plant height, height of insertion of the first pod, number of pods per plant, weight of one thousand grains and productivity. The averages were compared by the Tukey's test at 5% of probability. The highest values obtained for AP was for the cultivar M 8349, for NVP was Brasmax Estrema and for PMG and productivity Brasmax Domínio presented the highest values. All cultivars presented heights of insertion of the first pod favorable for mechanized harvesting. The use of seed inoculation in the soy cultivars tested favored the weight of one thousand grains and productivity only for the Brasmax Domínio cultivar. Although the cultivars tested presented an adequate insertion height of the first pod and weight of thousand grains, probably, the low values obtained for height and number of pods per plant resulted in a lower productivity.