Rootstocks for the grapefruit hybrid Sweetie ('Oroblanco') under organic and conventional management

The yield (kg ha(-1)) and quality (weight, total soluble solids (TSS%), TSS:acid ratio, antioxidative activity in juice and peel) of Sweetie (Citrus maxima x C. paradisi, also known as oroblanco) fruit grown on the non-traditional 'Poorman's Orange' rootstock were similar to and often better than that of Sweetie grown on the commercial standard sour orange rootstock, which is susceptible to tristeza. Yield and quality of fruit grown on 'Swingle' citrumelo rootstock were inferior to that of sour orange. Fruit grown on 'Marsh' grapefruit as a rootstock were of similar or slightly lesser quality than 'Poorman'. Sweetie fruit grown organically were higher in TSS% and titratable acidity than those grown in a conventionally-managed grove, but with a significant decrease in yield, regardless of rootstock.