ABSTRACT The mixed-model methodology is an alternative to select genotypes for traits highly influenced by the environment. In addition, this method allows FOR estimating the repeatability coefficient and predicting the number of assessments needed for a selection process to increase reliability. This study aimed to determine the minimum number of evaluations necessary for a reliable selection process and to estimate the variance components used for predicting genetic gains between and within half-sib families of elephant grass ( Cenchrus purpureus (Schumach.) Morrone ) using the mixed-model methodology. Half-sib families were generated using genotypes from the Active Germplasm Bank of Elephant Grass. The experiment was performed in a randomized block design with nine half-sib families, three replicates, and eight plants per plot. We evaluated 216 genotypes (individual plants) of elephant grass. The deviance analysis was carried out, genetic parameters were estimated, gains between and within families were predicted, and repeatability coefficients were obtained using Selegen software. There was genetic variability for selection within the families evaluated. The reliability values found above 60 % for plant height and number of tillers and above 80 % for dry matter yield suggest that only two evaluations are required to select superior genotypes with outstanding reliability. Sixteen genotypes were identified and selected for their productive potential, which can be used as parents in elephant grass breeding programs for bioenergy production.

ABSTRACT Elephant grass stands out among lignocellulosic biomass plants utilized for second-generation biofuel production due to several advantageous characteristics compared to other raw materials. Its short production cycle and ability to thrive in adverse soil and climate conditions contribute to its appeal. Additionally, breeders seek genotypes with high productivity potential and adaptability to various favorable cultivation environments. This study aimed to estimate genetic parameters, predict genetic values using mixed models (REML/BLUP), and evaluate stability and adaptability for energy biomass production in elephant grass genotypes. The experiment was conducted in Campos dos Goytacazes, RJ, Brazil, utilizing a two-replicate experimental block design that included 40 elephant grass genotypes. Four harvest assessments were performed between 2016 and 2019. Genetic parameter estimation and selection of superior genotypes based on genetic value using the REML/BLUP procedure were performed using Selegen software. Stability and adaptability analyses were obtained through the harmonic mean of genotypic values (HMGV), enabling the identification of stable and highly productive genotypes. Genotypes 17, 18, 32, 16, 36, 6, 15, 31, and 34 exhibited outstanding performance in terms of HMGV, indicating enhanced stability, adaptability, and simultaneous productivity, thus ensuring robustness in cultivation. These selected genotypes hold potential for future breeding programs aimed at improving elephant grass yield for biomass production.

Abstract The study of adaptability and yield stability is essential for the selection and recommendation of new cultivars. Thus, this study determined the adaptability and yield stability of black bean genotypes for cultivar recommendation using a GGE biplot. To this end, nine trials were carried out at different locations in the state of Rio de Janeiro. Eleven genotypes were evaluated in three growing seasons, in a randomized block design, with three replications. Adaptability and stability of grain yield were analyzed by the GGE biplot method. The effects of genotypes, environments and of the genotype - environment interaction were significant, which explained the different responses of the genotypes to the tested environments. The GGE biplot analysis revealed Macaé as an ideal district for testing and high yield, adaptability, and stability of performance were observed for genotype CNFP 15290, which can be recommended for grain production in the state of Rio de Janeiro.

RESUMO: A utilização de modelos mistos na avaliação de cruzamentos dialélicos é uma opção altamente oportuna para a fidedigna predição dos valores genéticos das progênies. Na cultura do pimentão, os híbridos são largamente explorados comercialmente, principalmente por suas características de importância econômica. O objetivo deste trabalho foi avaliar o potencial de híbridos resultantes de um dialelo parcial entre cinco linhagens de pimentão desenvolvidas para o sistema de cultivo hidropônico e dois híbridos simples, utilizando modelos mistos. Foram realizados cruzamentos no esquema de dialelo parcial entre as linhagens (L1B, L6, L7, L18 e L19) e os híbridos simples ‘Valdor’ e ‘Atlantis’. As plantas foram cultivadas em sistema hidropônico com substrato e irrigadas três vezes ao dia com solução nutritiva. Com base em modelos mistos, foram avaliadas as características: diâmetro médio de frutos (DF); comprimento médio de frutos (CF); número médio de frutos por planta (NFP); massa média de frutos (MMF); produção precoce (PP) e massa média de frutos por planta (MFP). A linhagem L6 foi a que expressou maior estimativa de capacidade geral de combinação para MFP, MMF e PP, revelando-se promissora para recomendação. O híbrido triplo que apresentou melhor capacidade específica de combinação para DF, MMF, MFP e PP, foi L6 x ‘Valdor’. Os híbridos triplos foram eficientes para incrementar a produtividade para as características de interesse com a aplicação da modelagem mista.

ABSTRACT: The use of mixed models for evaluating diallel crosses is a highly timely option to the reliable prediction of progeny genetic values. In the sweet pepper crop, hybrids are commercially explored on a large scale, mainly because of their characteristics of economic importance. This study aimed to assess the potential of hybrids obtained from a partial diallel among five sweet pepper lines developed for the hydroponic cultivation system and two simple hybrids, by applying mixed models. It was performed crosses in the partial diallel scheme among the (L1B, L6, L7, L18, and L19) lines and the simple hybrids ‘Valdor’ and ‘Atlantis’. Plants were cultivated in hydroponic system with substrate and irrigated three times a day using nutrient solution. On the basis of mixed models, the following traits were assessed: mean fruit diameter (FD), mean fruit length (FL), mean fruit number per plant (FNP), mean fruit mass (FM), early yield (EYIELD), and mean fruit mass per plant (FMP). The L6 line was the one that showed the highest estimate of general combination capacity for FMP, FM, and EYIELD, proving to be promising for recommendation. The hybrid that provided the best specific combining ability for FD, FM, FMP, and EYIELD was L6 x ‘Valdor’. Triple hybrids were efficient to maximize yield for the traits of interest by the use of the mixed model.