Desempenho agronômico de laranja 'Valência' em combinação com 13 porta-enxertos no Rio Grande do Sul, Brasil

The objective of this work was to evaluate the agronomic performance of 'Valencia' sweet orange ( Citrus sinensis ) tree, in combination with 13 rootstocks cultivated in soil and climate conditions of the Brazilian state of Rio Grande do Sul. The following agronomic variables were evaluated: scion height and volume, plant production, production efficiency, productivity, fruit diameter, fruit mass, peel mass, juice yield, soluble solids content, titratable acidity, soluble solids:acidity ratio, ascorbic acid, peel color, antioxidant capacity, and phenolic compounds. A randomized complete block experimental design was used, with three replicates and nine plants per plot, in a two-factor arrangement (13 rootstocks and the 2015 and 2016 harvests). The following rootstocks stood out: TSKC × TRDP-023 for its juice yield (54.0 and 51.7%), soluble solids:acidity ratio (8.66 and 6.99), and ascorbic acid (49.3 and 51 mg 100 g -1 ); and the citrandarin 'San Diego', for its higher phenolic-compound content (106.4 and 74.9 100 g -1  gallic acid), coloration (76.2 and 75.9 ho), and ascorbic acid (42.2 and 44.7 mg 100 g -1 ). The TSKC × TRDP-026 and TSKC × CTQT1434-004 rootstocks induce canopy formation and productive precocity in 'Valencia' orange trees grown in the southern region of the state of Rio Grande do Sul state, in the first few years of growth.