Progresso genético em caracteres agronômicos de soja

Abstract

Soya cultivation (Glycine max) plays an important economic role for the world and Brazil. The present work had the objective of characterizing the genetic progress in agronomic traits of soybean cultivars, establishing which changes in the yield components most impacted in the increase of productivity. The experiment was implemented in the municipality of Paro Branco-PR, in the agricultural crop 2016/2017 in the experimental area of the Universidade Tecnológica Federal do Paraná (UTFPR). A total of 30 soybean genotypes released between 1965 and 2011 were evaluated in experimental units consisting of four rows of five meters in length spaced 0.5 m apart (10 m2) with sowing density of 350,000 seeds per ha-1, using a randomized block design with three replicates. To obtain grain yield, only the two central lines of each plot were collected, resulting in a useful area of 5 m2. The number of nodes per plant (NNP), number of branches per plant (NRP), number of pods per plant, number of plants per plant (NNP), number of plants per plant (NVP), crop index (CI), plant height (PE), weight of a thousand grains (PMG) and grain yield (GR). In the period 1965 to 2011, the average RG of 3987.5 kg-ha-1 was found, ranging from 2696.61 kg-ha-1 in the less productive genotype to 5127.04 kg-ha-1 for the most productive. The RG was positively associated with the year of launch (0.71 *), with an increment in the RG of 36,96 kg-ha-1 per year. There was a positive correlation between RG and RB (0.31 *), IC (0.60 *), AIPV (0.42 *) and NVP (0.35 *). The components NRP (-0.57 *), EP (-0.45 *), and ACAM (-0.37 *) presented negative correlation with the RG. The association with release year was positive for the components RB (r = 0.51 *), AIPV (r = 0.54 *), NVP (r = 0.55 *), and RG (r = 0.71 *), whereas for the NVP (r = -0.69 *), EP (r = -0.57 *) and ACAM (-0.31 *) the association was negative.