Abstract The objective of this work was to evaluate the combining ability of S3 forage maize (Zea mays) progenies for traits related to forage yield and bromatological quality, with and without the ear, as well as to evaluate the ability of testers to discriminate progenies for these traits. The trials were carried out in the 2017/2018 and 2018/2019 crop seasons, in the municipality of Guarapuava, in the state of Paraná, Brazil. Topcross hybrids obtained from the crosses of 28 S3 maize progenies with three testers were evaluated. The following forage qualitative traits of the whole plant and of the plant without the ear were evaluated: neutral and acid detergent fibers, lignin, and in situ dry mass digestibility, as well as digestible dry mass yield of the whole plant. The progenies that stood out for forage qualitative traits were 85.1 and 42.1 for the whole plant and for the plant without the ear, respectively. For the qualitative and productive traits of whole-plant forage, progenies 91.1, 106.2, 126.2, 138.1, 152.1, 235.1, and 251.1 are promising to continue in the breeding program aiming to generate hybrids with a high yield and fiber quality. Testers LEM3 and AG8025 are efficient in discriminating progenies for forage yield and bromatological traits.

Resumo O objetivo deste trabalho foi avaliar a capacidade de combinação de progênies S3 de milho (Zea mays) forrageiro em relação a características relacionadas com o rendimento e a qualidade bromatológica da forragem, com e sem a espiga, bem como avaliar a capacidade de testadores para a discriminação das progênies para estas características. Os ensaios foram realizados nas safras de 2017/2018 e 2018/2019, no município de Guarapuava, no estado do Paraná, Brasil. Foram avaliados os híbridos topcross obtidos dos cruzamentos de 28 progênies de milho S3 com três testadores. As seguintes características qualitativas da forragem da planta inteira e da planta sem a espiga foram avaliadas: fibras em detergente neutro e ácido, lignina e digestibilidade in situ da massa seca, além do rendimento da massa seca digerível de toda a planta. As progênies que se destacaram quanto às características qualitativas da forragem foram 85.1 e 42.1 para a planta inteira e para a planta sem a espiga, respectivamente. Para as características qualitativas e produtivas da forragem da planta inteira, as progênies 91.1, 106.2, 126.2, 138.1, 152.1, 235.1 e 251.1 são promissoras para continuar no programa de melhoramento com vistas à geração de híbridos com altos rendimento e qualidade de fibra. Os testadores LEM3 e AG8025 são eficientes na discriminação de progênies para as características produtivas e bromatológicas das forragens.

ABSTRACT. Maize forage is commonly used as silage in milk and beef cattle livestock production systems. Despite the wide variety of maize hybrids with high potential for grain production, few available hybrids have been developed exclusively for forage aptitude. The present study aimed to select S3 maize progenies derived from the single hybrid AS1572 based on the combining ability of forage traits in topcrosses with testers AG8025, 70.H26.1, and MLP102. The 135 resulting topcross hybrids were assessed in partial diallel in Guarapuava and Rio Bonito do Iguaçu, Paraná State, Brazil. Were evaluated the contents of neutral detergent fiber (NDF, %DM) and acid detergent fiber (ADF, %DM), forage dry matter yield (DMY, t ha-1), and in situ digestibility of forage dry matter (DIG, %DM). For all evaluated traits, the variability allowed us to select superior progenies. Progenies 3.1, 22.1, and 39.1stood out in terms of NDF, ADF, and DIG, whereas progenies 47.1, 73.1, 79.1, and 90.2 were efficient in increasing the forage dry matter yield. The testers AG8025 and 70.H26.1, of narrow genetic base, are the best to explore genetic variability among progenies.

ABSTRACT Super sweet corn breeding must develop hybrids that fully meet the expectations of the market. In this sense, the determination of keytraits for the selection of sweetcorn genotypes is a fundamental condition for breeding success. The objective of this work was to identify key traits for the selection of promising and contrasting genotypes of super sweet corn. The experiments were carried out in Guarapuava (PR), in two sowing dates. Seventeen traits related to the yield and quality of the ear were evaluated. To perform the multivariate analysis, data were subjected to diagnosis of multicolinearity, analysis of canonical variables, genetic divergence, hierarchical clusters, factor analysis, and canonical correspondence analysis. Grain yield, yield of dehusked ears, and number of commercial ears were considered related key traits in the identification of promising super sweet corn genotypes. Hybrid D3-20 × D5-41 presented higher averages than the others, considering the yield related keytraits.