No abstract

In breeding of sweet sorghum hybrids, non-additive genetic effects are important in phenotypic expression of the traits of interest. The aim of this study was to evaluate the general combining ability (GCA) of sweet sorghum lines and the specific combining ability (SCA) of the hybrids for agronomic and technological traits. Five fertility restorer lines, four male-sterile lines, and their hybrids from partial diallel crosses were evaluated in experiments laid out in a 5 x 6 triple rectangular lattice design in the municipalities of Lavras, MG and Sete Lagoas, MG, Brazil. Diallel analysis was performed using the Griffing model adapted to partial diallel crosses. There was a significant effect of GCA and SCA for most of the traits evaluated, indicating the participation of additive or dominant genes in inheritance. The restorer lines CMSX508, BRS 511, CMSXS643, and CMSXS646 show potential for use as parents in sorghum breeding programs.

This study was conducted to identify the allelic interactions and genetic effects involved in genetic control of quantitative traits in Capsicum annuum. Six generations (P 1 , P 2 , F 1 , F 2 , BC 1 and BC 2) were used to study the variances, means and allelic interactions of 16 quantitative traits evaluated. The additive part of the phenotypic variance found for plant height, number of peppers per plant, days to flowering and days to fruiting lead to the conclusion that phenotypic selection in the F 2 generation are likely effective in obtaining genetic gains. According to the reduced model, the traits of canopy width, fruit width and number of seeds per fruit were not influenced by epistatic effects, but only by additive and dominant effects, which allows selection of superior individuals in segregating generations or improvement of these traits by means of hybridization.

The selection of sweet sorghum genotypes is based on multiple agronomical and technological traits. The objectives of this study were to evaluate the effectiveness of inter-trait recovery information in improving the selective accuracy of the predicted genetic values of sweet sorghum progenies, and to compare several selection indices in terms of selection gains using single-and multi-trait mixed models. The trials were conducted in two sites. The traits flowering time, plant height, green mass production, total soluble solids content, and tons of Brix per hectare were assessed. Significant genetic variance was observed for all traits, except for total soluble solids content. The multi-trait analysis provided more accurate estimates of genetic parameters and predictions of the progeny genetic values, and higher selection gain than the singletrait analysis. The direct selection for TBH and the FAI/BLUP index resulted in balanced genetic gains for the assessed traits.