Selection of Soybean Genotypes in the Central Region of Tocantins

Brazilian agribusiness enables two consecutive harvests in the same year using early soybean cultivars. Understanding the interaction between environments and soybean genotypes is crucial for adapting cultivars and ensuring production stability. This study aimed to select early soybean genotypes in the central region of Tocantins. The experiment was conducted in Porto Nacional under rainfed and irrigated conditions, evaluating 40 soybean genotypes, including lines and commercial cultivars. A randomized block design with three replications was used, with plots consisting of four 5-meter rows spaced 0.50 meters apart. Grain productivity (sc. ha-1), cultivation cycle (days), and lodging index were analyzed. Data were subjected to variance analysis via SISVAR software, and means were compared using the Scott & Knott test at a 5% probability level. The coefficient of variation and accuracy estimates assessed experimental precision. Nineteen genotypes exceeded the national average for grain productivity. The cultivation cycle ranged from 91 to 109 days, with an 18-day variation. Under rainfed conditions, none of the genotypes showed susceptibility to lodging, but in the irrigated condition, 9 genotypes exhibited high lodging scores. Four genotypes—20285INT1835, 20204INT108701, 18610INT21205, and 20652INT102372—stood out for combining high productivity, absence of lodging, and an early cycle of 99-101 days. These genotypes demonstrate significant potential for agricultural systems in the Tocantins region.