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Selection of desirable characters for papaya genetic improvement programs associated with hydric and thermal stress1 1 Research developed at Universidade Estadual Paulista “Júlio de Mesquita Filho”, Faculdade de Engenharia de Ilha Solteira, Ilha Solteira, SP, Brazil

Seleção de caracteres para programas de melhoramento genético do mamoeiro sob estresse hídrico e térmico

HIGHLIGHTS:

Young seedlings provide efficient data for identifying promising characteristics for the evaluation of papaya varieties.

With only two components, it was possible to explain 70% of the variability for both cultivars.

Principal component analysis (PCA) helps identify desirable characteristics of seedlings, thereby reducing costs and time.

ABSTRACT

Papaya cultivation is widespread in Brazil, particularly in the states of Bahia and Espírito Santo, where most commercial plantations are concentrated. Owing to the economic and social importance of papaya, the present study aimed to determine the explanatory variables between the genotypes of two cultivars: Golden (from the Soil group) and Tainung Nº 1 hybrid (from the Formosa group), cultivated under high temperatures and hydric stress. The genotypes containing more desirable agronomic characteristics were identified for use in plant genetic improvement programs. Principal component analysis (PCA) was applied to select the desirable genotypes for Golden and Tainung Nº 1 cultivars based on specific variables analyzed for two groups of variables; for group 1, the plant height, stem diameter, leaf length, leaf width, and leaf number were analyzed, whereas for group 2, the leaf and root dry mass, stem dry mass and fresh mass of 10 discs, fresh mass, and stem and root fresh mass were analyzed. When exposed to hydric and thermal stress, the Tainung Nº 1 cultivar outperformed the Golden cultivar for the evaluation characteristics selected for use in genetic improvement programs.

Key words:
Carica papaya L.; variability; multivariate analysis

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