Choosing a rootstock for citrus fruit is a crucial decision made by growers. Important traits that should be considered include tolerance to diseases and pests, scion compatibility, soil and climate conditions, suckering, and precocity, because all of these can affect the yield, quality, and health of the tree (Roose, 2014). A poor choice of rootstock will have negative effects on the plant, including increased disease rates and lower fruit production. Specific rootstocks are known to differ in regard to fruit quality (Roose, 2014), and the choice of rootstock involves chemical, flavor, and liking effects (Benjamin et al., 2013).
The ‘DaisySL’ mandarin is known for its low seed count, mid-to-late season ripening, medium-to-large fruit size, and excellent flavor (Roose and Williams, 2010). Originating from researchers at the University of California, Riverside, the fruit was created from irradiated budwood of the ‘Daisy’ mandarin (Fortune × Fremont) and officially released in June 2009. Although it was cited as being of high quality, past assumptions were based on chemical measurements, including °Brix and titratable acidity (Roose and Williams, 2010).
Recent research of consumer preferences for mandarins and oranges has shown that preference is dependent on many sensory modalities, such as taste, texture, and flavor attributes (Goldenberg et al., 2015; Obenland et al., 2009; Simons et al., 2018a, 2018b; Tietel et al., 2011). Few studies have evaluated children’s preferences regarding mandarins; however, children are among the target consumers for mandarins (Simons et al., 2018a).
During this study, ‘DaisySL’ mandarins (C. reticulata Blanco) were grown at the University of California Lindcove Research and Extension Center in Exeter, CA. Budwood was grafted to three different common rootstocks found in California: Rough lemon (C. macrophylla, C. jambhiri Lush.), Trifoliate [P. trifoliata (L.) Raf.], and Carrizo (C. sinensis L., Osbeck Poncirus trifoliata L.). In California, oranges from Rough lemon rootstocks have higher yields, but the fruit tend to have lower levels of soluble solids and acid (Roose, 2014). Carrizo and Trifoliate are both considered good to excellent rootstocks for internal fruit quality (sugar, acid, and juice content) in California (Roose, 2014). These rootstocks were chosen for the ‘DaisySL’ variety due to their known differences in fruit production characteristics, especially fruit quality, for oranges. The aims of this research were to determine the differences in chemical profiles between rootstocks and to determine if these differences caused sensory or consumer liking differences. Because past research revealed higher soluble solids and acids in oranges (Roose, 2014), we hypothesized that the fruit grown on the Carrizo and Trifoliate rootstocks would be preferred by both adults and children.
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