Influence of Plant Density on the Physiological Quality of Barley Seeds

Abstract

Plant population density influences intraspecific competition and may affect the physiological quality of the seeds produced. This study aimed to evaluate the physiological quality of barley seeds produced under different plant population densities. The experiment was conducted in a randomized complete block design using a 5 × 2 factorial arrangement, consisting of five plant densities (150, 200, 250, 300, and 350 plants m⁻²) and two barley cultivars (BRS Brau and BRS Cauê), with four replications. Seed physiological quality was evaluated over two growing seasons using the first germination count, standard germination, accelerated aging, shoot and root dry matter, electrical conductivity, and thousand-seed weight tests. Cultivar responses varied according to plant density and growing season. In the first season, BRS Brau performed better at lower plant densities, whereas BRS Cauê showed superior performance at higher densities. In the second growing season, BRS Cauê maintained higher seed physiological quality at greater plant densities, particularly in the vigor and germination tests, whereas BRS Brau performed better at lower densities in the accelerated aging and thousand-seed weight tests. These findings demonstrate that responses to plant population density are genotype-dependent, highlighting the importance of optimizing plant density to maximize both seed production and physiological quality in barley.