Caracterização pós-colheita e divergência genética de acessos de umbuzeiro

Abstract

In Brazil, the umbu has gained more and more attention, due to its high socioeconomic potential, still in the process of domestication and few areas cultivated with selected materials. Despite its importance, there are few studies aimed at increasing the information base and the possibilities of use. The objective of this study was to evaluate the fruits of the collection of umbuzeiro accessions belonging to EPAMIG-Norte, in terms of physical and chemical characteristics. And also to estimate the genetic divergence through morphological markers, obtained by the evaluation of the plants in the field and to relate it with the divergence obtained through ISSR markers. To evaluate physical and chemical characteristics, the experimental design used was completely randomized, with 16 treatments (accessions of umbu from EPAMIG) with four replications with 10 fruits each, during two harvests. The physical analyzes were performed: fruit mass (g), longitudinal (cm) and transversal (cm) diameters, firmness (FIRM). To obtain the chemical characteristics, the content of soluble solids (TSS), titratable acidity and color analysis were evaluated. Joint analysis of variance (p<0.05) was performed and, when significant, the means were compared using the Scott-Knott mean grouping (p<0.05). To obtain the morphological characteristics, the plant height, crown area, trunk height, trunk circumference of 12 plants of each accession were evaluated. Molecular genotyping was performed by extracting DNA from leaf primordia using ISSR primers. Dissimilarity based on molecular markers was estimated using the Gower Index. Individual dendrograms were obtained for each analysis using the UPGMA method.A tanglegram was generated to illustrate the similarities between the associations of the two dendrograms. For the physical and chemical attributes of the fruits, there was a significant interaction between the harvests only for the TSS and FIRM variables, and the 2022 harvest showed better averages. In the 2021 harvest, it was observed that there was no significant difference between the accessions for the titratable acidity variable, while for the other variables there was a significant effect. In the morphological characterization, the effect of accessions was significant for all evaluated traits. The formation of four distinct groups was observed, with high variability, in relation to the means of accessions, except for the characteristic trunk circumference and trunk height. Based on the genetic diversity estimated via ISSR markers among the umbuzeiro accessions, it was possible to verify the formation of two distinct groups. The comparison between the morphological and molecular data revealed divergences and similarities. The umbu accessions under study present little variation for the soluble solid attributes and pH. For fresh consumption and/or processing, the accessions Epamig 06 and Epamig 13 stand out because they have a high percentage of pulp, small percentage of rind, and high SS/AT ratio. The EPAMIG 04 and EPAMIG 12 accessions were the ones that most diverged by morphological analysis and the EPAMIG 08 accession was the most distant by molecular analysis, being able to be tested in crosses to evaluate the segregating populations and possible obtainment of heterosis.