Abstract In plant breeding, the dialelic models univariate have aided the selection of parents for hybridization. Multivariate analyses allow combining and associating the multiple pieces of information of the genetic relationships between traits. Therefore, multivariate analyses might refine the discrimination and selection of the parents with greater potential to meet the goals of a plant breeding program. Here, we propose a method of multivariate analysis used for stablishing mega-traits (MTs) in diallel trials. The proposed model is applied in the evaluation of a multi-environment complete diallel trial with 90 F1’s of simple maize hybrids. From a set of 14 traits, we demonstrated how establishing and interpreting MTs with agronomic implication. The diallel analyzes based on mega-traits present an important evolution in statistical procedures since the selection is based on several traits. We believe that the proposed method fills an important gap of plant breeding. In our example, three MTs were established. The first, formed by plant stature-related traits, the second by tassel size-related traits, and the third by grain yield-related traits. Individual and joint diallel analysis using the established MTs allowed identifying the best hybrid combinations for achieving F1’s with lower plant stature, tassel size, and higher grain yield.

Abstract: This work aimed to determine variance components and genetic parameters, as well as phenotypic, genetic and environmental correlations among black oat (Avena strigosa) families grown in different crop season. Seventy-six black oat families and three controls (BRS Madrugada, BRS Centauro, BRS 139 Neblina) were evaluated in two crop seasons (2016 and 2017), using families with intercalary controls experimental design. The results reveled high potential of black oat families to compose a breeding program, due to families and controls variance were similar, variance components expressed greater genetic variance origin for crop season. Panicle weight and panicle grain weight presented high heritability and, these are correlated with panicle length. Thus, these traits can be used to select superior genotypes. Divergent meteorological conditions between crop seasons expressed few variations among phenotypic, genetic and environmental correlations, and it did not alter magnitude and sense of phenotypic and genetic correlations.

O objetivo deste trabalho foi caracterizar morfologicamente a dissimilaridade genética entre 25 genótipos de milho (Zea mays L.), visando a seleção dos mais divergentes e de maior potencial produtivo, por meio da análise multivariada, em cinco ambientes de cultivo do Sul do Brasil. As linhagens endogâmicas dos dois grupos heteróticos foram provenientes do banco de germoplasma da empresa KSP Sementes Ltda. Utilizaram-se 15 linhagens como genitores femininos e oito linhagens como genitores masculinos. Os ensaios foram conduzidos na safra agrícola 2011/2012 em cinco ambientes, com delineamento de blocos completos ao acaso com três repetições por local. Foram avaliados 15 caracteres de interesse agronômico. A divergência genética foi avaliada por meio do método de agrupamento de Tocher e UPGMA. As estimativas da D² indicam os pares de genótipos 6 e 22 como mais distantes geneticamente, e 1 e 14 os pares mais similares. Foram identificados nove grupos divergentes em ambos os métodos de agrupamento. Os caracteres profundidade de grãos, diâmetro do sabugo, massa de sabugo, diâmetro de espiga e peso de 100 grãos foram os principais determinantes na quantificação da divergência genética. Para o melhoramento de milho, os genótipos com maiores potenciais são 5, 15, 12, 20, 9, 25 e 10.

The aim of this study was to morphologically characterize the genetic dissimilarity among 25 maize (Zea mays L.) genotypes in order to select the most divergent and higher yield potential, by multivariate analysis, in five cultivation environments in southern Brazil. The inbred lines of the two heterotic groups were from the genebank company KSP Seeds Ltda. Fifteen inbred lines were used as female parents and eight inbred lines as male parents. The tests were conducted during the harvest 2011/2012 in five environments, in randomized complete block design with three replications per location. We evaluated 15 characters of agronomic interest. Genetic divergence was assessed by the clustering method of Tocher and UPGMA. Estimates of D² indicated genotype pairs 6 and 22 as genetically more distant, and 1 and 14 the most similar pairs. Nine different groups were identified in both clustering methods. The depth of grain, cob diameter, cob weight, ear diameter and weight of 100 grains characters were the main determinants in the quantification of genetic divergence. For breeding purposes, genotypes 5, 15, 12, 20, 9, 25 and 10 are those of higher potential.

Verificou-se as estimativas das capacidades de combinação de genitores de batata em gerações iniciais de seleção. Os experimentos foram realizados na Embrapa Clima Temperado, Pelotas (RS). Foram avaliadas 20 famílias derivadas de nove genitores cruzados em esquema parcial 4 x 5 (C-1750-15-95; 2CRI-1149-1-78; C-1786-6-96 e 'Eliza'; 'White Lady'; 'Asterix'; 'BP-1'; 'Vivaldi' e 'Ágria'). As famílias foram avaliadas na geração de plântula e na primeira geração de campo, utilizando o delineamento experimental de blocos com tratamentos ao acaso, com três repetições. A parcela consistiu de uma amostra de 15 genótipos de uma família. Nas duas gerações foram avaliados os caracteres rendimento, número e massa média de tubérculo. Os dados foram submetidos às análises de variância conjunta e dialélica parcial. Para rendimento verificou-se efeito gênico predominantemente aditivo, enquanto para número e massa média de tubérculo constatou-se tanto efeito aditivo e não aditivo, igualmente importantes. 2CRI-1149-1-78 e 'White Lady' revelaram-se os genitores mais promissores para os três caracteres, enquanto 'Ágria' destacou-se para massa média. As gerações expressaram estimativas similares de capacidade geral de combinação.

The combining ability of potato genotypes was estimated in early generations of selection. The experiments were carried out at Embrapa Clima Temperado, in Pelotas, Brazil. Twenty potato families derived from nine genotypes crossed in a 4 x 5 partial mating design (C-1750-15-95, 2CRI-1149-1-78, C-1786-6-96 and 'Eliza'; 'White Lady', 'Asterix', 'BP-1', 'Vivaldi' and 'Ágria') were evaluated. The families were evaluated in seedling and first field generation, in a randomized complete block design, with three replications of 15 genotypes. Each plot consisted of a sample of 15 genotypes of a family. In the two generations, yield, number and average tuber weight were evaluated. The data were submitted to analysis of variance and to partial diallel analysis. For yield, the gene additive effects predominated, while for tuber number and average tuber mass, both additive and non additive effects were equally important. 2CRI-1149-1-78 and 'White Lady' showed to be the most promising parents for the three traits, while 'Ágria' revealed superiority for mean tuber weight. The two generations presented similar estimative of general combining ability.