-The objective of this work was to evaluate the productivity and quality of papaya fruits (Carica papaya) of the Solo (12 genotypes) and Formosa (9 genotypes) heterotic groups over two harvest seasons. The experiment was conducted under field conditions in the municipality of Pinheiros, in the state of Espírito Santo, Brazil, in a randomized complete block design. Ten morpho-agronomic and physicochemical variables of the fruits were measured in winter (210-300 days after planting) and summer (450-540 days after planting). The data were subjected to the combined analysis of variance, to the breakdown of the genotype x environment interactions, and to the grouping of means by the Scott-Knott test. Although harvest season affected the evaluated characteristics, it did not alter the classification of the genotype. In the Solo group, the H 36-45 and UC 15 hybrids stand out due to their greater productivity, fruit weight, and soluble solids contents. In the Formosa group, the Rubi Incaper 511 cultivar shows greater productivity, higher number of commercial fruits, and lower number of deformed fruits over both evaluated harvest seasons.Index terms: Carica papaya, agronomic performance, environmental effect, genotype evaluation. Produtividade e qualidade de frutos de mamão Formosa e Solo em duas épocas de colheitaResumo -O objetivo deste trabalho foi avaliar a produtividade e a qualidade de frutos de mamoeiro (Carica papaya) dos grupos heteróticos Solo (12 genótipos) e Formosa (9 genótipos), em duas épocas de colheita. O experimento foi conduzido em condições de campo em Pinheiros, ES, em delineamento de blocos ao acaso. Dez variáveis morfoagronômicas e físico-químicas dos frutos foram avaliadas no inverno (210 a 300 dias após o plantio) e no verão (450 a 540 dias após o plantio). Os dados foram submetidos à análise de variância conjunta, à decomposição da interação genótipo x ambiente e ao agrupamento das médias pelo teste de Scott-Knott. Embora a colheita em diferentes épocas tenha influenciado as características avaliadas, não alterou a classificação dos genótipos. No grupo Solo, destacam-se os híbridos H 36-45 e UC 15, por suas maiores produção e massa do fruto e por seu alto teor de sólidos solúveis. No grupo Formosa, a cultivar Rubi Incaper 511 apresenta maior produção, maior número de frutos comerciais e menor número de frutos deformados nas duas épocas de colheita avaliadas.Termos para indexação: Carica papaya, desempenho agronômico, efeito ambiental, avaliação de genótipos.
Selection of superior genotypes based on the simultaneous responses to different characteristics is a fundamental strategy in plant breeding. This study aimed to compare the efficiency of four selection index constructed using phenotypic and genotypic values in a segregating population of the cultivar Rubi Incaper 511. Eight morpho-agronomic variates and the severity of black-spot and phoma-spot were evaluated under field conditions. The classical selection index were calculated based on non-standardized phenotypic means (NSM), standardized means (SM), and genotypic values predicted by REML/BLUP (GVP), using predetermined economic weights. Additionally, the rank sum (RS) was obtained on the basis of the classification of individuals in these three selection index. For ten characteristics, the selected individuals showed a higher mean than did the original population. The best selection differential values were obtained by SM, however, the highest degree of coincidence among the selected individuals was obtained between GVP and RS (80%). The index used were efficient at selecting individuals with higher soluble solids and lower diseases severity evaluated. Therefore, for the papaya breeding programs, different selection index need to be evaluated to maximize genetic gain.
Few cultivars of papaya from the Formosa group are available to producers, and the development of new genotypes is indispensable. Thus, the use of effective selection strategies to obtain more productive cultivars and better quality fruits is also necessary. The aim of this study was to select of half-sib families (HSF) of papaya using the methodology of mixed models. Nineteen HSFs from the Incaper’s papaya breeding program were evaluated in a randomized block design with five replicates and nine plants per plot. The selection was made based on fruit mass (FM), pulp thickness (PT), soluble solids content in pulp (SS) and number of fruits (NF). The genetic parameters and genotypic values were estimated by the REML/BLUP procedure. The selected HSFs increased FM by 26.1%; the PT in 10.5%; the SS in 7.5% and; the NF in 13.0%. The additive heritability within the progenies and the individual variation coefficient obtained indicate that the selection between and within the HSFs can provide greater genetic gains. The selection based on the REML/BLUP methodology was efficient to obtain simultaneous genetic gains for all variables under study despite the negative correlation between them.
-Correlations and path analysis allow the understanding of the interrelations between characteristics of interest to the plant breeding. However, in order for their results to be reliable, the undesirable effect of multicollinearity must be excluded. The objective of this study was to estimate the correlations and their partitioning in direct and indirect effects, by path analysis, on the fruit production per plant (FP) of papaya from the heterotic Solo and Formosa groups, using two different strategies to circumvent multicollinearity. Eleven agronomic variables were evaluated in twelve papaya genotypes from the Solo group and nine from the Formosa group. Path analysis was obtained with the FP as the basic variable and to eliminate multicollinearity were used the discard of variables and the ridge path analysis. For the Solo group, fruit length and pulp thickness had greater direct effects on FP. In the Formosa group, the number of commercial fruits had a direct and indirect effect on FP. The two methodologies used to circumvent multicollinearity had high coefficient of determination, with better values for the ridge path analysis. The results indicated that the interrelation between the study characters was different in the Solo and Formosa groups. Thus, indirect selection strategies should be specific for each heterotic group. Index terms: Carica papaya L., ridge path analysis, indirect selection, correlations. Análise de trilha sob multicolinearidade para produção de mamoeiro dos grupos Solo e FormosaResumo -As correlações e a análise de trilha permitem o entendimento das inter-relações entre características de interesse ao melhoramento de plantas. Porém, para que os resultados dessas análises sejam confiáveis, é preciso excluir o efeito indesejado da multicolinearidade. O objetivo desse trabalho foi estimar as correlações e seus desdobramentos em efeitos diretos e indiretos, pela análise de trilha, sobre a produção de frutos por planta (FP) de mamoeiro dos grupos heteróticos Solo e Formosa, usando duas diferentes estratégias para contornar a multicolinearidade. Foram avaliadas 11 variáveis agronômicas em 12 genótipos de mamoeiro do grupo Solo e nove do grupo Formosa. A análise de trilha foi obtida tendo o FP como variável básica e para eliminar a multicolinearidade foi utilizado o descarte de variáveis e a análise de trilha em crista. Para o grupo Solo, o comprimento do fruto e a espessura da polpa tiveram maiores efeitos diretos sobre o FP. No grupo Formosa, o número de frutos comerciais teve grande efeito direto e indireto sobre FP. As duas metodologias utilizadas para contornar a multicolinearidade tiveram alto coeficiente de determinação, com melhores valores para a análise de trilha em crista. Os resultados indicaram que a inter-relação entre os caracteres em estudo foi diferente nos grupos Solo e Formosa. Assim, as estratégias de seleção indireta devem ser específicas para cada grupo heterótico. Termos para indexação: Carica papaya L., análise de trilha em crista, seleção indireta, correlações.
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