Desempenho agronômico, fitossociologia de plantas daninhas e qualidade de sementes em função da densidade de semeadura de cultivares de feijão-comum no semiárido mineiro

Abstract

The objective of this work was to evaluate the agronomic performance, phytosociology of weed and physiological quality of seeds of common bean cultivars, according to sowing density, under the cultivation conditions of the Minas Gerais semi-arid. The treatments were arranged in a 6x4 factorial scheme taking into accounting six common bean cultivars (BRSMG Realce, BRS Ártico, BRS Estilo, BRS Esteio, BRSMG Uai e BRSFC402), and four sowing densities (50, 100, 200 and 500 thousand seeds ha-1 ). The experimenttal design was a randomized block design, with four replicates. Grain yield with its primary components were evaluated, phytosociology of weed and seed quality. Data were subjected to individual and combined analysis of variance taking into accounting years of cultivation. The highest grain yield was obtained at a density of 315 to 380 thousand seeds ha-1 and final population of 187 to 215 thousand plants ha-1 , for the cultivar BRSMG Realce; 300 thousand seeds ha-1 and from 147 to 186 thousand plants ha-1 , for cultivar BRS Ártico; from 300 to 320 thousand seeds ha-1 and from 150 to 245 thousand plants ha-1 , for cultivar BRS Estilo; from 280 to 330 seeds ha-1 and from 173 to 255 thousand plants ha-1 , for cultivar BRS Esteio; from 280 to 340 thousand seeds ha-1 and 187 to 208 thousand plants ha-1 , for cultivar BRSMG Uai; from 270 to 310 thousand seeds ha-1 and from 185 to 212 thousand plants ha-1 , for cultivar BRS FC402. The most of the cultivars keep the mass of 100 grains according to the standard of its group. In most studies condition, dicotyledonous species predominated, especially in the largest sowing densities. There was a predominance of Poaceae, Asteraceae, Fabaceae e Comelinaceae families. In general way, the highest values of importance and cover value index were obtained by the Digitaria horizontalis, Dactyloctenium aegyptium, Eleusine indica, Brachiaria plantaginea, Amaranthus spp. e, mainly for Sena obtusifolia species. The seeds of BRS FC402, BRSMG Uai and BRS Esteio cultivars present germination according to standards required for production and commercialization. BRS Realce, BRS Esteio, BRSMG Uai e BRS FC 402 cultivars were not affected by increasing sowing density, in the tests of first germination count, seedling emergence, emergence speed index, and plantlets length, being influenced by the seeds vigor. In general, the increase in sowing density has little interference on seed vigor characteristics of common bean cultivars.