UPGMA clustering reveals maturity-dependent diversity for fruit quality traits in acerola

Characterizing genetic diversity for fruit quality traits can support germplasm management and the

identification of contrasting parents for acerola breeding. This study assessed the multivariate

diversity of 35 acerola (Malpighia emarginata DC.) genotypes at the big green and red-ripe stages

over two production cycles. The experiment followed a randomized complete block design with

three blocks per cycle. Fruit diameter, mass, firmness, soluble solids (SS), titratable acidity (TA),

SS/TA ratio, and ascorbic acid (AA) content were evaluated. Genotypic values were predicted by

REML/BLUP separately for each maturity stage. Standardized predicted genotypic values were

used to calculate Euclidean distances, followed by hierarchical clustering using the unweighted

pair-group method with arithmetic mean (UPGMA). Five groups were identified at each maturity

stage. At the big green stage, group sizes were 2, 12, 19, 1, and 1 genotypes, with the largest group

representing 54.3% of the germplasm. BRS Rubra and Okinawa formed isolated groups, indicating

distinctive multivariate profiles. At the red-ripe stage, groups comprised 2, 3, 4, 6, and 20

genotypes, with 57.1% concentrated in the largest group. Cophenetic correlations were 0.742 and

0.650 for the big green and red-ripe stages, respectively. The most divergent pairs were ACO 03 ×

BRS Rubra at the big green stage (distance = 8.10) and Camta × PROG 052 at the red-ripe stage

(8.15). Changes in group composition and in the most divergent pairs indicate that multivariate

fruit-quality diversity is maturity-dependent. Therefore, maturity stage should be considered when

characterizing acerola germplasm and identifying contrasting genotypes for breeding.