Morphoagronomic genetic diversity of Brazilian melon accessions based on fruit traits

Morphoagronomic characterization and genetic diversity analysis of fruit quality traits and production were performed in 42 Brazilian melon accessions and four commercial reference cultivars. The experiment was undertaken in three distinct environments in the Northeast Region, Brazil, which is the most productive culturing state. Analysis of variance (ANOVA) indicated significant differences among the locations for all evaluated traits, indicating that the locations were different from each other and influence the phenotypic gain. However, significant interactions among genotypes and locations were detected only in six of the studied characteristics, demonstrating that the edafoclimatic conditions quantitatively influenced the expression of important descriptors for fruit quality and production. The ANOVA performed for the variation in each location showed significant effect in all descriptors, suggesting wide variability among accessions and commercial cultivars, focusing on the Brazilian genetic resource. Differences in quantitative behavior characteristics and, consequently, in the groupings of genotypes of each accession and cultivars, in relation to the locations was found by Scott-Knott grouping test. Genetic diversity inferred by the Ward-Modified Location Model (Ward-MLM) multivariate analysis, allowed the detection of genetic divergence among accessions with the distribution of the germplasm analyzed in distinct canonical groups. The differences between the average quantitative characteristics, observed in the genotypes of the same accessions in different locations, influenced the grouping of these genotypes. Among the four groups formed from the Ward-MLM analysis, only the commercial cultivars were clustered together, suggesting that these cultivars differ from the other accessions, but have close characteristics introgreded during the process of genetic improvement. An association between these groups and the botanical classification of accessions was also observed, indicating genotypic conservation for some descriptor expression. The soluble solids content contributed was the most relevant fruit trait to contributed for multivariate clustering formation. The genetic variability detected in these accessions should be further used for breeding, to obtain more prolific cultivars, with high productivity that are adapted to the different production regions.