Assessment of fruit quality of sweet orange trees grafted on different rootstocks through Mixed Models (REML/BLUP)

The objective was to relate, based on quality characteristics, the potential of fifty-nine (59) sweet orange cultivars grafted onto the 'Sunki Tropical' tangerine rootstock and the 'Trifoliata' citrandarin hybrids 'San Diego', 'Riverside', and 'Indio', using 236 combinations with mixed models. The orchard was established in 2015. The following parameters were evaluated at stage III (fruit maturation): fruit weight (g), juice yield (JY, %), total soluble solids content (TSS, °Brix), titratable acidity (TA, g of citric acid per L-1), and the Ratio (TSS/TA). The mixed model methodology (REML/BLUP) was used to estimate/predict the fruit maturation parameters for different scion and rootstock combinations. The scion and rootstock combinations differed statistically for total soluble solids, titratable acidity, ratio, and juice yield. The rootstocks 'San Diego', 'Riverside', and 'Indio', and the 'Sunki Tropical' mandarin induced juice yields (55.05% to 60.05%), soluble solids (10.70°Brix to 12.38°Brix), and titratable acidity (0.50% to 0.66% citric acid) in sweet orange trees that were within quality standards. In the ranking, the combinations, in order, of 'Pera CNPMF D-9'/'Riverside', 'Pera Selection CNPMF C-32'/'Riverside', 'Pera Selection CNPMF D-3'/'San Diego', 'Pera Selection Olímpia'/'Sunki Tropical', 'Valência Selection CNPMF'/'Sunki Tropical', 'Diva'/'Sunki Tropical', 'Melrosa'/'Índio', 'Pera CNPMF D-6'/'Sunki Tropical', and 'Pera C-21'/'Riverside', scion and rootstock, respectively, stood out. These are combinations with greater potential for commercial exploitation because they meet quality standards.