Teores de clorofila e o rendimento de feijoeiro em sistema de integração lavoura pecuária

Abstract

Brazil is the world's largest producer of common bean and although it is a staple of the Brazilian population, its productivity is still low. As a result, breeding programs seek to raise productivity. The objective of this work was to identify if there is a correlation between chlorophyll content and grain yield, and to verify the cause and effect relationships between yield components on grain yield of the crop at different nitrogen rates. The experiment was carried out in the city of Abelardo Luz - SC in the Livestock Integration System. The design used in the experiment was a 2x2x4 trifractor scheme with subdivided plots. In the main plots, two levels of grazing intensity were evaluated, characterized by two pasture management heights (high height (AA) = 30 cm and low height (BA) = 15 cm), two nitrogen fertilization times (NG) and nitrogen applied to the pasture (NP), with a dose of 200 kg ha-1 as urea. In the subplots, which constituted the experimental units, four nitrogen doses (0, 50, 100 and 150 kg ha-1) were evaluated. Chlorophyll collections (a, b and total) were performed using a chlorophyllometer (ClorofiLOG® model CFL 1030). The variables were evaluated at the reproductive stage of the culture (R5, R6, R7 and R8). At harvest, the same plants used for evaluating chlorophyll were collected and evaluated the following yield components: grain yield per plant (RGP), plant height (AP), first pod insertion height (AIPV), average length of (CMV), number of grains per pod (NGV), number of grains per plant (NGP) and weight of pod per plant (PVP). In order to verify the association between the productive variables of the culture (AP, AIPV, NGV, NGP, CMV and PVP) and the chlorophyll content with the RGP, the coefficients of simple linear correlation of Pearson were obtained; and then the trail analysis was performed to verify the direct and indirect effects of the variables (yield components) on crop yield. For all statistical analyzes, the Genes Program version 3.1 was used. Although significant, the relationship between chlorophyll content (a, b, total and a / b) with grain yield per plant in common bean is low. The yield components are mostly positive and high with grain yield per plant. The character that has the greatest direct effect on the yield of grains per plant is the NVP at doses 0, 50 and 100 kg of N ha-1; and at the 150 kg dose of N ha-1 was the PVP character. The characters AP, NVP, NGV and CVP act indirectly on the yield per plant, via PVP.