Desenvolvimento do feijoeiro comum preto submetido a diferentes níveis de desfolha artificial e fontes de nitrogênio

Abstract

The plants are prone to attack by defoliation insects, which can reduce the leaf area of the plants, generating low productivity. The incidence of these pests can reduce black bean production. One of the alternatives that can be used is inoculation with diazotrophic bacteria that supply nitrogen to the plants making it more resistant to pest attack. Thus, the objective of this work was to evaluate the development of common black bean (Phaseolus vulgaris L.) submitted to different levels of artificial defoliation and nitrogen sources. The experiment was carried out in a greenhouse at the Federal University of Recôncavo da Bahia, at the Cruz das Almas - Bahia campus, with a 5 x 3 factorial design, five levels of defoliation (0, 25, 50, 75 and 100%) and three sources of nitrogen (Rhizobium tropici, mineral nitrogen and absolute control). At 25 days after sowing, the plants were submitted to levels of artificial defoliation and at 50 days of the experiment the chlorophyll index (a, b and total) was analyzed. Afterwards, the plants were harvested in aerial part and root, dried for 72 hours at 60 ° C in order to evaluate dry mass of shoot (DMS), dry mass (DM), total dry mass (TDM), number of nodules, nodule dry mass (NDM), efficiency (ECN) and efficacy (ESN). Up to the level of artificial defoliation of 50%, the black bean plants presented the dry matter of the similar aerial part when submitted to the sources of nitrogen. In the defolum above 75% the inoculation provided the highest dry matter yield of the aerial part of the common black bean plants in the vegetative phase.