Abstract
Fruit samples that are in the same size range (sized samples) are often used to estimate juice content, soluble solids content (SSC), titratable acidity (TA) and ratio of SSC: TA. Typically fruit samples are taken around the tree at a 3-6 ft height. We compared fruit quality of a 20-fruit sized sample of 'Valencia' oranges [Citrus sinensis (L.) Osb.] on Carrizo citrange [C. sinensis (L.) Osb. × Poncirus trifoliata (L.) Raf.] or rough lemon (C. jambhiri Lush.) rootstocks with whole tree harvests at seven commercial groves in Florida. Ten trees were sampled and harvested at each location. Juice content samples averaged 6.8% higher than the whole tree measurements and SSC and TA means were 4.7 and 7.2% lower, respectively. SSC content of the sized sample and actual whole tree values were poorly correlated, probably because SSC is generally much higher in the top vs the lower portions of the canopy and SSC is quite variable within the tree. Sample and whole tree juice content levels were moderately correlated and TA content sample levels were highly correlated with whole tree measurements. Within tree variation for these quality factors is lower than for SSC. Therefore, sized samples provide a relative measure for estimating whole tree juice quality for juice content and TA but are less reliable for estimating SSC.
