Predição de ganho genético com diferentes índices de seleção em sorgo sacarino [Sorghum bicolor (L.) Moench]

Abstract

The sweet sorghum shows up as a promising crop to sugarcane industry in order to offer an alternative to ethanol production, using the same industrial parks already in place. Therefore, it is necessary to obtain consistent genetic gains every year for several characters. These characters are divided in agronomic and technical or industrial in order to supplement each other aiming at the increase of ethanol production per unit area. For selection based on multiple characters it is extremely necessary to know the characters to be used, as well as their genetic correlations to assist in the choice of characters to be used. The objective of this study was to estimate the genetic gain based on multi-select agricultural and industry characters in sweet sorghum genotypes. The selection indexes allow helping the simultaneous selection so that it is possible measure the genetic gain per generation of selection for all selected characters. There were evaluated 196 sweet sorghum genotypes, 189 progenies and 7 witnesses at the experimental station of the Embrapa Maize and Sorghum in Sete Lagoas, Minas Gerais in 2014. The experimental design was a unbalanced square lattice with three replications. There was genetic gain in all traits. The Sum of the Ranks index (IR) was negatively correlated with the Standardized by the Average index (IPM), Modified Standardized by the Average index (IPM*) and Z index (IZ) and had the lowest rates of coincidence between the indices. The selected progeny showed a great potential to become varieties or parental for generations of hybrids.