Long-term Evaluation of Mature-line and Juvenile-line ‘Valencia’ and ‘Vernia’ Sweet Orange Budlines on ‘Carrizo’ Rootstock

Field trials are critically important to the citrus industry because they provide scientific data from replicated plantings that can be used to determine which rootstock-scion combinations to plant. The field trial reported here was a semi-commercial-scale scion trial involving several selections of ‘Valencia’ and one ‘Vernia’ selection on the ‘Carrizo’ citrange rootstock. The purpose of this trial was to evaluate ‘Valencia’ and ‘Vernia’ scion selections from various sources to identify accessions that could complement the existing scion cultivar range and provide a wider harvest window. The scions consisted of advanced seedless somaclonal ‘Valencia’ selections, irradiated material, and an assortment of other selections, including accessions from Australia, Brazil, and California. Of special interest were young (juvenile line) sources. A secondary objective was to assess the relative response of the selections to huanglongbing (HLB), which was discovered in Florida during this trial. The location of this trial was Lake County, FL, USA, and the trees were planted in Mar 2000. A randomized complete block design was used with four replications of multiple tree plots. Data collected included total soluble solids, titratable acidity, sugar-to-acid ratio, pounds-solids per box, number of boxes per tree, pounds-solids per acre, cumulative pounds-solids per acre, and HLB rating. There were significant differences among the scions for several variables, including boxes of fruit per tree, pounds-solids per acre, HLB rating, and others. The findings of this research suggest that there are differences in performance among scion selections for a variety of horticultural traits important to citrus growers and processors.