Dry matter accumulation in genotypes of bean submitted to different levels of nitrogen

Abstract

The objective of this study was to verify the response of dry matter accumulation in bean lines (Phaseolus vulgaris L.) to different levels of nitrogen fertilizers. Six genotypes ('BRSMG Majestoso', 'Pérola', MA-I-18.13, 'Ouro Negro', 'BRSMG Talismã', and MA-I-2.5) were evaluated in Lavras, testing three N levels (0, 60, and 120 kg/ha) and using ammonium sulphate as N source. The experimental design adopted was the randomized block design in a 6 x 3 factorial structure with three replications and the plots were composed of five 5-m rows. The seeds were sown in November 2005 and July 2006. Total dry mass of five competitive plants was evaluated after 35 days from sowing, harvested from a pre-determined place in the useful area of the plots. This process was repeated every ten days until the harvest. The grain yield was also evaluated in one of the rows of the useful area of the plots. It was observed that regarding the dry mass accumulation, the genotypes did not present different responses at the N levels and the average increase per kg/ha applied N was 6.75 kg/ha grains. The genotype BRSMG Majestoso is the most responsive, with 14.4 kg/ha grains per kg applied N whereas the most tolerant is the MA-I-2.5 with1.8 kg/ha grains per kg N.