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A B S T R A C TSorghum bicolor (L.) (Moench), which stands out for dry matter yield per hectare, has been considered as potential raw material for biofuels and electricity generation. It has a production cycle of six months, possibility of mechanization of cultivation and harvest and good adaptation to most regions of Brazil. Sorghum genotypes were evaluated for agronomic potential and chemical composition favorable to the production of second-generation ethanol. Three brown midrib (bmr) sorghum mutant hybrids were compared to three conventional hybrids. The bmr sorghum mutant hybrids are associated with reduced lignin content, making these genotypes more promising to the enzymatic conversion processes of the biomass. Sorghum biomass showed a high potential in terms of biomass production, with an average dry matter yield of 26.57 Mg ha −1 . Brown midrib sorghum hybrids showed significantly lower lignin contents than conventional hybrids and demonstrated the potential for cellulosic ethanol production.

Sorghum [Sorghum bicolor (L.) Moench] biomass hybrids with high productivity and enhanced levels of lignin are seen as a promising alternative of feedstock for direct burning in ovens designed for cogeneration of electricity. The objective of this study was to estimate the genetic combing capacity of biomass sorghum lines and conduct multivariable selection of photosensitive biomass sorghum hybrids for use in cogeneration. Thirty‐six photosensitive hybrids, the control BRS716, and 12 parental lines were evaluated in a seven‐by‐seven triple lattice design at two locations, and 12 characters were evaluated. There was superiority of additive effects on the genetic control of all the characteristics studied in both environments, less for female lines in the diallelic analysis of F1 hybrids. The inclusion of parents in the estimates of combining capacities indicated predominance of dominance effects involved in the genetic control of the traits analyzed. The results demonstrate the action of epistasis of the dwarf genes present in the female lines for the biomass parameter and the false interpretation when these lines are included in the diallelic analysis. With the use of the index based on factor analysis and genotype–ideotype distance (FAI‐BLUP index), four factors were established, which separated the characteristics of production and quality, as well as the two environments, resulting from the high hybrid × environment interaction. With the index, five hybrids with higher potential for burning (H5‐5, H2‐1, H1‐1, H1‐5, and H5‐1) were selected. However, no hybrids obtained gains for the characteristics of production and quality, simultaneously, which indicates the need for genetic improvement of the parents used in the program.

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Understanding the genotype‐by‐environment interactions (GEI) is crucial to release sweet sorghum [Sorghum bicolor (L.) Moench] cultivars with stable and high agronomic performance under tropical environments. Therefore, linear mixed models could be used to face this challenge by leveraging the biological process of GEI into cultivar recommendation. The goals of this study were: (a) to explore GEI patterns under tropical conditions to select stable and high‐yielding genotypes for energy‐use in the bioethanol industry; and (b) to evaluate the advantages of linear mixed models taking into account simultaneously the genetic and the residual correlations across environments and the genomic relationship between genotypes. The breeding dataset was comprised of 41 genotypes evaluated for Tonnes of brix per hectare (TBH) in late‐stage trials over 32 tropical environments. The models incorporating simultaneously the genomic relationship matrix of genotypes and the genetic and the residual correlations across environments showed the lowest values of Akaike Information Criterion (AIC) compared to the standard phenotypic models, and also increased the expected genetic gains of TBH across years. Based on the best models selected by AIC, the genotypes 38 (CMSXS5006), 6 (BRS511), 5 (CMSXS633), 9 (CMSXS637), and 12 (BRS506) exhibited the highest productivity in TBH. Particularly, the genotype 9 (CMSXS637) showed broad stability and high productivity under tropical environments, besides the desirable traits for bioethanol production. These results highlight the importance of modeling the genomic relationship between genotypes and the genetic and the residual correlations across environments to increase the breeding efficiency of sweet sorghum under tropical environments.