ABSTRACT Manual phenotyping for papaya Carica papaya (L) breeding purposes limits the evaluation of a great number of plants and hampers selection of superior genotypes. This study aimed to validate two methodologies for the phenotyping of morpho-agronomic plant traits using image analysis and fruit traits through image processing. In plants of the ‘THB’ variety and ‘UENF/Caliman-01’ hybrid two images (A and B) were analyzed to estimate commercial and irregularly shaped fruits. Image A was also used in the estimation of plant height, stem diameter and the first fruit insertion height. In ‘THB’ fruits, largest and smallest diameters, length, and volume were estimated by using a caliper and image processing (IP). Volume was obtained by water column displacement (WCD) and by the expression of ellipsoid approximation (EA). Correlations above 0.85 between manual and image measurements were obtained for all traits. The averages of the morpho-agronomic traits, estimated by using images, were similar when compared to the averages measured manually. In addition, the errors of the proposed methodologies were low compared to manual phenotyping. Bland-Altman's approach indicated agreement between the volume estimated by WCD and EA using caliper and IP. The strong association obtained between volume and fruit weight suggests the use of regression to estimate this trait. Thus, the expectation is that image-based phenotyping can be used to expand the experiments, thereby maintaining accuracy and providing greater genetic gains in the selection of superior genotypes.

RESUMO Os objetivos deste trabalho foram gerar estimativas de capacidade combinatória de 22 linhagens de mamoeiro com testadores do grupo 'Solo' e 'Formosa' em esquema de top cross e identificar híbridos agronomicamente superiores. As linhagens foram selecionadas em gerações de retrocruzamentos para conversão sexual, tendo como genitor recorrente, o genótipo dióico 'Cariflora' e como doador a linhagem elite ginóico-andromonóica, 'SS 783'. As linhagens per se, os híbridos top crosses (híbridos T1 e híbridos T2) e duas testemunhas comercias foram avaliados em um delineamento em látice 8x8 quanto ao número de nós sem fruto (NNSF-un), número de frutos deformados (NFD-un), número de frutos comerciais (NFC-un), peso médio de fruto (PMF-g), comprimento do fruto (CF-mm), diâmetro do fruto (DF-mm), espessura média da polpa (EP-cm), firmeza do fruto (FF-N), firmeza da polpa (FP-N), teor de sólidos solúveis (TSS-°brix) e Produtividade (PROD-t ha-1). Obtiveram-se as estimativas de capacidade especifica de combinação pela diferença entre a média de cada híbrido obtido de um testador, com a média geral dos cruzamentos com o mesmo testador. A análise de variância realizada com as médias ajustadas revelou variabilidade genética entre grupos de tratamentos para todas as características avaliadas, bem como dentro de cada grupo de tratamento. Considerando os híbridos T1, as combinações que melhor conciliaram as estimativas de CEC para as características produtivas e de qualidade de frutos foram: L3xT1, L8xT1, L10xT1, L11xT1, L16xT1, L17xT1 e L20xT1. Para os híbridos T2 foram: L12xT2, L13xT2, L17xT2, L21xT2 e L22xT2.

ABSTRACT The aim of this study were to generate estimates of combining ability in 22 lines of papaya using testers from the 'Solo' and 'Taiwan' group in a top-cross scheme, and identify those hybrids which are superior agronomically. The strains were selected from generations backcrossed for sexual conversion, with the dioecious genotype Cariflora as recurrent parent, and the elite ginoic -andromonoic line, SS 783, as donor. The lines themselves, the top cross hybrids (T1 hybrids and T2 hybrids), and two commercial controls were evaluated in an 8 x 8 lattice design for number of nodes with no fruit (NNSF-un), number of deformed fruit (NFD-un), number of commercial fruit (NFC-un), average fruit weight (PMF-g), fruit length (CF-mm), fruit diameter (DF-mm), average pulp thickness (EP-cm), fruit firmness (FF-N), pulp firmness (PF-N), level of soluble solids (TSS-°brix) and productivity (PROD-t ha-1). Estimates of specific combining capacity were obtained from the difference between the average for each hybrid obtained from the tester and the overall average of crossings with the same tester. The analysis of variance carried out with the adjusted average values revealed genetic variability between treatment groups for all the evaluated characteristics, as well as within each treatment group. Considering the T1 hybrid, the combinations that best reconciled the CEC estimates for the characteristics of production and fruit quality were L3xT1, L8xT1, L10xT1, L11xT1, L16xT1, L17xT1 and L20xT1; for the T2 hybrids the combinations were L12xT2, L13xT2, L17xT2, L21xT2 e L22xT2..