Estimativas de parâmetros genéticos e seleção para múltiplas características em sorgo para fins forrageiro

Abstract

Sorghum is a versatile crop with potential for forage production, being an alternative for silage production. The improving sorghum crop for forage purposes, it is necessary to know the genetic variation associated with target traits of interest, as well as the potential per se of the parents through estimates of genetic parameters. The objective of this study was to obtain estimates of genetic parameters for agronomic and bromatological traits in sorghum lines for forage purposes, as well as to select promising lines based on multiple traits and obtain genetic gains. A diverse set of 100 sorghum lines was evaluated, including biomass, biomass/bmr, forage, as well as dual-purpose forage/sweet, from Embrapa Maize and Sorghum. The experiments were conducted in the 2020/2021 and 2021/2022 crop seasons and laid out in 10 × 10 triple lattice design. Data were analyzed using the mixed model approach. The estimated parameters were genetic variance, heritability and selective accuracy on line-mean basis , and genetic correlation between traits. Predictions of the genetic values of the lines were obtained and the FAI-BLUP index was applied for selection based on multiple traits. The measured traits were: green mass productivity (PMV), dry matter percentage (MS), dry mass productivity (PMS), acid detergent fiber (FDA), neutral detergent fiber (FDN), cellulose (CEL), hemicellulose (HEM) and lignin (LIG). There was genetic variation among lines for all traits. The PMV trait was highly correlated to PMS. The chemical traits or cell wall components were correlated with each other. The lines selected based on the FAI-BLUP index were: 54, 57, 56, 58, 53, 61, 4, 5, 55, 74, 60, 62, 10, 13 and 9, being the most promising lines for a forage sorghum breeding program. The expected genetic gains with the selection and recombination of these selected lines as parents were significant for all traits.