RESUMO: A seleção de combinações que apresentem os melhores genitores e o conhecimento sobre os efeitos gênicos que controlam as características, são possibilitadas pelo uso da análise dialélica. O objetivo deste estudo, foi selecionar os genitores com alta frequência de alelos favoráveis e populações segregantes com maior potencial para produzir progênies superiores, e entender os efeitos genéticos no controle das características estudadas. Assim, 15 genitores foram divididos em dois grupos e cruzados em esquema de dialelo parcial 7×8, obtendo o total de 56 combinações híbridas. Parte das sementes F1 foram avançadas para geração F2. As combinações em duas gerações (F1 e F2) foram avaliadas em campo experimental, em delineamento em blocos ao acaso, com duas repetições, entre os meses de junho e outubro de 2022, em Viçosa, Minas Gerais, Brasil. As variáveis avaliadas foram espigamento, dias até a maturação (ciclo), altura da planta, comprimento da espiga, massa de cem grãos e produção de parcela. A análise dialélica foi realizada pelo modelo de Geraldi e Miranda-Filho, para dialelo parcial, adaptado do método de Griffing. O efeito aditivo predominou para o controle dos caracteres analisados. Os genitores CD 1303, CD 151, BRS 254, ORSFEROZ, ORS Guardião e ORSSENNA, apresentaram frequência de alelos favoráveis para diferentes características. No total, 41 combinações foram selecionadas, sendo, 20 em F1 e 21 em F2. Destas, foram identificadas sete populações de alto potencial genético para originar progênies.

ABSTRACT: The selection of combinations that include the best parents and the understanding of the genetic effects controlling the traits can be made using diallel analysis. This study selected parents with a high frequency of favorable alleles and segregating populations with the greatest potential to produce superior progenies, as well as to understand the genetic effects controlling the studied traits. For this end, 15 parents were divided into two groups and crossed in a 7×8 partial diallel scheme, resulting in a total of 56 hybrid combinations. Some of the F1 seeds were advanced to the F2 generation. The combinations in both generations (F1 and F2) were evaluated in an experimental field in a randomized complete block design, with two replicates, between June and October 2022, in Viçosa, Minas Gerais, Brazil. Days to heading, days to maturation, plant height, spike length, hundred-grain weight, and plot yield were assessed. A diallel analysis was performed using the Geraldi and Miranda-Filho model for partial diallel, adapted from Griffing’s method. Our results suggested a predominance of additive effects. The parents CD 1303, CD 151, BRS 254, ORSFEROZ, ORS Guardião and ORSSENNA exhibited favorable alleles for different traits. In total, 41 combinations were selected, 20 from F1 and 21 from F2 generations. Among these, seven populations were identified as having high genetic potential for producing superior progenies.

ABSTRACT Estimating the combining ability in wheat (Triticum aestivum L.) parents is a crucial tool for selecting promising segregating populations with potential to generate genotypes adapted to the Brazilian tropical regions, supporting the wheat production expansion. This study aimed to estimate the general and specific combining abilities of wheat parents and segregating populations, in order to develop progenies with greater genetic potential for tropical environment. During the winter harvest, nine parents and 20 F2 populations obtained through a partial diallel mating scheme (4 × 5) were evaluated using a randomized complete block design, with two replications. The evaluated traits included days to heading, plant height, tan spot, leaf rust, number of spikelets per spike, 100-grain mass and grain yield. The data were processed using diallel analysis. The general combining ability (GCA) effect was significant for days to heading, leaf rust and 100-grain mass in the group 1, and for leaf rust, number of spikelets per spike and grain yield in the group 2. The specific combining ability was significant for 100-grain mass, with the crosses TBIO Aton × ORS Madrepérola and TBIO Astro × ORS Madrepérola standing out, with at least one parent showing a high GCA for this trait. Additive genetic effects predominated in the expression of the evaluated traits. The parents TBIO Astro and ORS Destak were identified as promising for deriving tropical wheat progenies with higher genetic potential.

RESUMO A estimação da capacidade de combinação de genitores de trigo (Triticum aestivum L.) é uma importante ferramenta para a seleção de populações segregantes promissoras com potencial de originar genótipos adaptados às regiões tropicais do Brasil e favorecer a expansão da triticultura. Objetivou-se estimar as capacidades geral e específica de combinação de genitores e populações segregantes de trigo, visando desenvolver progénies de maior potencial genético ao ambiente tropical. Durante a safra de inverno, nove genitores e as 20 populações F2 obtidas a partir de cruzamentos em esquema dialélico parcial (4 × 5) foram conduzidos sob delineamento de blocos casualizados, com duas repetições. Avaliaram-se o espigamento, altura de planta, mancha amarela, ferrugem da folha, número de espiguetas por espiga, massa de cem grãos e rendimento de grãos. Os dados foram submetidos à análise dialélica. O efeito da capacidade geral de combinação (CGC) foi significativo para espigamento, ferrugem e massa de cem grãos no grupo 1, e ferrugem, número de espiguetas por espiga e rendimento de grãos no grupo 2. Houve efeito significativo da capacidade específica de combinação para massa de cem grãos, com destaque para os cruzamentos TBIO Aton x ORS Madrepérola e TBIO Astro x ORS Madrepérola, em que pelo menos um dos genitores apresenta alta CGC para o referido caráter. Houve predominância do efeito aditivo na determinação dos caracteres analisados. Os genitores TBIO Astro e ORS Destak são promissores para derivação de progénies de trigo tropical com elevado potencial genético.

Abstract In many cases, traditional analysis of breeding trials based on analysis of variance (ANOVA) do not allow a suitable genetic evaluation. Alternatively, mixed model-based approaches create the possibility of dealing with unbalanced data and modeling spatial trends. The aims of this study were to compare the goodness-of-fit of the model and the genotype ranking through different residual modeling approaches and to select the best performing tropical wheat genotypes based on the best-fitting model. A panel of tropical wheat genotypes was evaluated in three field trials conducted between 2020 and 2021 for grain yield. Linear mixed model analyses were used on the data to estimate the genetic parameters and to predict the genotypic values in analyses of single- and multi-environment trials. Accounting for spatial trends in the analyses of single- and multi-environment trials provides better outcomes than the compound symmetry model does.

RESUMO: As análises de correlações canônicas baseadas nas correlações genotípicas, permitem determinar associações entre grupos de caracteres e realizar a seleção direta ou indireta de genótipos superiores. Objetivou-se com este trabalho investigar a existência de relações lineares e multivariadas entre caracteres de alta e baixa herdabilidade via análise de correlações canônicas com base nas correlações genotípicas. O experimento foi conduzido no Campo Experimental Professor Diogo Alves de Melo da Universidade Federal de Viçosa, em Viçosa, Minas Gerais. 90 cultivares de trigo foram avaliadas sob o delineamento alpha-lattice 9 × 10, com três repetições e parcelas constituídas por quatro linhas de três metros espaçadas a 0.20 metros. Os grupos canônicos foram estabelecidos entre altura de espiga e planta, dias para o espigamento, número de espiguetas por espiga e número de grãos por espiga (Grupo I) e, peso de espiga, massa de grãos da espiga, massa de 100 grãos, peso hectolitro e produtividade de grãos (Grupo II). Houve dependência entre os grupos estabelecidos, o que permitiu a investigação das relações entre os caracteres com base em seus valores genotípicos. Os caracteres ciclo e altura de plantas podem ser utilizados para a seleção indireta de genótipos superiores em peso hectolitro e produtividade, fatores estes importantes para indústrias e produtores.

ABSTRACT: Canonical correlation analysis based on genotypic correlations allows determining the associations between groups of traits and carrying out the direct or indirect selection of superior genotypes. This study investigated the existence of linear and multivariate relationships between high and low heritability traits via canonical correlation analysis based on genotypic correlations. The experiment was conducted at the Professor Diogo Alves de Melo Experimental Field at the Universidade Federal de Viçosa, in Viçosa, MG. 90 wheat cultivars were evaluated under a 9 × 10 alpha-lattice design, with three replications and plots consisting of four rows of three meters spaced at 0.20 meters. Canonical groups were established between spike height and plant height, days for heading, number of spikelets per spike, and number of grains per spike (Group I) and, spike weight, spike grain mass, 100-grain mass, hectoliter weight, and grain yield (Group II). There was dependence between the established groups, which allowed the investigation of the relationships between traits based on their genotypic values. The traits cycle and plant height can be used for indirect selection of genotypes superior in hectoliter weight and grain yield, which are important factors for industries and farmers.

ABSTRACT A large set of variables is assessed for progeny selection in a plant-breeding program and other agronomic fields. The meta-analysis of the coefficient of variation (CVe) produces information for researchers and breeders on the experimental quality of trials. This analysis can also be applied in the decision-making process of the experimental plan regarding the experimental design, the number of repetitions, and the treatments and plants/progenies to be measured. In this study, we evaluated the dataset distribution and the descriptive statistics of CVe through the Frequentist and Bayesian approaches, aiming to establish the credibility and confidence intervals. We submitted CVe data of ten wheat (Triticum aestivum L.) traits reported in 1,068 articles published to the Bayesian and Frequentist analyses. Sample data were analyzed via Gamma and normal models. We selected the model with the lowest Akaike Information Criterion (AIC) value, and then we tested three link functions. In the Bayesian analysis, uniform distributions were used as non-informative priors for the Gamma distribution parameters with three ranges of q~U (a,b,). Thus, the prior probability density function was given by: p θ = 1 β - α , θ ∈ α , β . The Bayesian and Frequentist approaches with the Gamma model presented similar results for CVe; however, the range Bayesian credible intervals was narrower than the Frequentist confidence intervals. Gamma distribution fitted the CVe data better than the normal distribution. The credible and confidence intervals of CVe were successfully applied to wheat traits and could be used as experimental accuracy measurements in other experiments.