Agronomic phenotyping of Setaria italica cultivated at different sowing times

Setaria italica is a C4 grass with a short growth cycle, high water-use efficiency, and great potential for biomass production, forage, and soil cover. However, in Brazil, information on its agronomic performance under different sowing dates and on its interactions with environmental factors, pests, diseases, and soil physical conditions is still limited, which restricts the establishment of efficient management strategies. Therefore, the objective of this study was to evaluate the agronomic phenotyping of the cultivar URNRS24 of Setaria italica under different sowing dates and to analyze the occurrence of weeds, insect pests, and diseases under field conditions. The experiment was carried out in Ijuí, Rio Grande do Sul, Brazil, using a randomized block design with three sowing dates and five replications. Variables related to emergence, phenology, growth, yield components, soil penetration resistance, and meteorological data obtained from the National Aeronautics and Space Administration (NASA POWER database) (2025) were evaluated. In sequence, They were subjected to analysis of variance, correlation, and regression analyses. The results showed that sowing date significantly affected crop development and productivity. Early august sowing favored individual plant growth and grain weight per plant due to lower stand density and reduced intraspecific competition, whereas sowing in September promoted more uniform growth and better climatic adaptation, although with higher incidence of foliar diseases. Thus, the choice of sowing date is a key factor determining the agronomic performance of Setaria italica under subtropical conditions.