Resumo -O objetivo deste trabalho foi avaliar descritores quantitativos e estimar parâmetros genéticos em genótipos de mamoeiro (Carica papaya). Foi instalado um experimento em blocos aumentados, para a avaliação de 27 genótipos, entre cultivares, variedades melhoradas e variedades locais, com o uso de 30 descritores relacionados à planta, folhas, flores, frutos e sementes. Após diversos ciclos de melhoramento, os genótipos ainda mostravam ampla variabilidade quanto aos descritores avaliados. A maior parte da variação fenotípica ocorreu em razão da variância genotípica. A herdabilidade variou de 60,48 a 99,05% e, em 80% dos casos, foi superior a 80,46%. A razão entre o coeficiente de variação genético e o ambiental foi maior do que a unidade para 63% das características. Há diferenças agronômicas suficientes para uso dos genótipos "per se" ou como parentais em programas de melhoramento, em razão de agregarem variação genética, qualidade de frutos e tipo agronômico.Termos para indexação: Carica papaya, desenvolvimento de variedades, melhoramento genético, seleção de parentais, variação genética. Evaluation of papaya genotypes using agronomic descriptors and estimation of genetic parametersAbstract -The objective of this work was to evaluate quantitative descriptors and to estimate genetic parameters in genotypes of papaya (Carica papaya). An experiment was settled using augmented blocks, for the evaluation of 27 genotypes, among cultivars, improved lines and local varieties with 30 descriptors related to the plant, leaves, flowers, fruit and seeds. After several cycles of breeding, the genotypes still showed broad variability for the evaluated descriptors. Most of the phenotypic variation occurred due to genetic variance. The heritability ranged from 60.48 to 99.05%, and in 80% cases it was higher than 80.46%. The ratio between genetic and environmental coefficients of variation, was greater than the unity for 63% traits. There are enough agronomic differences which allow for the use of the genotypes "per se" or as parents in breeding programs because they aggregate genetic variation, fruit quality and agronomic type.

This study was conducted to define a list of sufficient minimum descriptors to distinguish between papaya genotypes quickly and precisely. To this end, 30 quantitative and 21 multi-category descriptors related to plant characteristics, such as leaves, flowers, fruit and seeds were evaluated in 27 genotypes of papaya, including crops, local varieties and improved lines. The quantitative descriptors were subjected to principal components analyses using the Singh and direct selection methods, whereas a correlation analysis was conducted for the qualitative descriptors. Eighteen and fifteen quantitative descriptors were discarded by the Singh and direct selection methods, respectively. However, considering the simultaneous analyses of these methodologies, 60% of the descriptors were selected to maximize the total variation of the genotypes. Six of the multi-category descriptors were monomorphic, and two were highly correlated with other characteristics and were discarded. The minimum descriptors that were selected had high discrimination potentials when they were analyzed together. Thus, for the purposes of the protection of varieties and the classification of the genotypes of papaya, there were found to be 18 quantitative and 13 multi-category minimum descriptors that contributed significantly to the total variation and possessed low correlation with each other. The elimination of descriptors did not entail a loss of information. Those descriptors that contributed most significantly to the first three principal components were the stem diameters, fruit lengths and widths, inflorescence peduncle lengths, thickness of fruit skin, leaf widths, dry and fresh seed weights and ratio between fruit lengths and widths and between total soluble solids and total titratable acidities.