Desempenho de comunidades de arroz híbrido em função da qualidade fisiológica das sementes e densidade populacional

Abstract

The objective of this study was to evaluate the effect of different arrangements for distribution of seed plants from high and low physiological quality along the line of sowing under different plant populations in communities of hybrid rice, watching the changes in the development and effects of intraspecific competition within communities. The experiment was conducted at Experimental e Didática do Departamento de Fitotecnia da Faculdade de Agronomia Eliseu Maciel (FAEM) using the hybrid Avaxi from Ricetec. The experimental design was a randomized block design with four replications. The treatments were three combinations of distribution of plants from seeds with high and low physiological quality, seeded in 4 populations of plants. The three combinations were all plants originated from seeds with high physiological quality (AA), a plant originating from seeds with high physiological quality interspersed with a plant originating from seeds of low physiological quality (Ab), all the plants originated from of low physiological quality (BB). The four populations were 63, 125, 250 and 500 plants/m², corresponding to densities of 25,50,100 and 200 kg ha-1. We used 20 cm spacing between rows. The two levels of physiological seed quality were obtained by use of a lot with the germination percentage of about 92% and accelerated aging 86%, considered high quality, and another of approximately 74% germination and accelerated aging 40% considered low physiological quality. It was concluded that the intraspecific competition between plants originating from seeds of different levels of physiological quality in communities of hybrid rice is enhanced, resulting in loss of dry biomass and grain yield in plants originated from seeds of low physiological quality; plants grown from seeds of low physiological quality have less competitive ability into communities of hybrid rice, the number of grains per panicle is the main component of yield affected by intraspecific competition the communities rice plants, and are responsible for yield losses, plants originated from high quality physiological seeds have behavior dominant originated about the plants from seed for reducing the quality, when arranged so adjacent in the row sowing; competitive effects among plants from seeds of high and low physiological quality were not affected by plant population.