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tion of sweetness of the fruit (Sater et al., 2021). Neither trait was affected by graft ing in any of the studied seasons. All fruit reached the expected TSS values for SHB ‘Patrecia’ (higher than 10 %) (Munoz, 2016). However TSS:TTA declined drastically dur ing late season in 2022, below the expected values (higher than 14 units). This decline in fruit quality (lower TSS and higher TTA) might be related to increasing night tempera tures during the late spring in Florida. Simi lar declines have been documented in straw berry (Menzel, 2022) and grape (Gaiotti et al., 2018). This was the only occasion when fruit quality was below the commercial stan dard. Since fruit from all treatments was af fected, these results suggest that sparkleberry rootstocks did not have an influence on the internal fruit quality of blueberry fruits. Summary Blueberry plants grafted onto sparkle berry rootstocks R1 and R2 produced more fruit than own-rooted blueberry plants start ing three years after planting in a minimally amended (50% of the recommended amount of pine bark) soil. Grafting reduced berry firmness, but fruit quality attributes met or exceeded commercial standards. These find ings suggest that grafting SHB onto sparkle berry clonal rootstocks is a promising ap proach to producing commercial yields of high-quality fruit in soils with higher pH and lower amounts of pine bark. Additional re search is necessary to identify rootstock-sci on combinations that maximize productivity and longevity while minimizing soil input requirements. References Cited Bowerman, J.R., Spiers, J.D., Coneva, E., Tilt, K.M., Blythe, E. K., Marshall, D.A. 2013. Propagation of sparkleberry (Vaccinium arboreum) improved via cutting type. Acta Hort. 1014, 385-388. https://doi. org/10.17660/ActaHortic.2013.1014.87 Cappai, F., Benevenuto, J., Ferrão, L. F. V., Munoz, P. 2018. Molecular and genetic bases of fruit firm ness variation in blueberry - a review. Agron. 8(9), p. 174. https://doi.org/10.3390/agronomy8090174

Casamali, B., Darnell, R. L., Kovaleski, A. P., Olm stead, J. W., Williamson, J. G. (2016a). Vegetative and reproductive traits of two southern highbush blueberry cultivars grafted onto Vaccinium arbore um rootstocks. HortScience 51, 7, 880-886. https:// doi.org/10.21273/HORTSCI.51.7.880 Casamali, B., Williamson, J. G., Kovaleski, A. P., Sargent, S. A., Darnell, R. L. (2016b). Mechanical harvesting and postharvest storage of two southern highbush blueberry cultivars grafted onto Vaccini um arboreum rootstocks. HortScience 51, 12, 1503 1510. https://doi.org/10.21273/HORTSCI11323-16 Darnell, R.L. and Hiss, G.K. 2006. Uptake and assimi lation of nitrate and iron in two Vaccinium species as affected by external nitrate concentration. J. Amer. Soc. Hort. Sci. 131:5– 10. https://doi.org/10.21273/ JASHS.131.1.5 Darnell, R. L., Williamson, J. G., Bayo, D. C., Har mon, P. F. 2020. Impacts of Vaccinium arboreum Rootstocks on Vegetative Growth and Yield in Two Southern Highbush Blueberry Cultivars. Hort Science 55(1), 40-45. https://doi.org/10.21273/ HORTSCI14585-19 Ehlenfeldt, M. K., Martin, R. B. 2002. A survey of fruit firmness in highbush blueberry and species-intro gressed blueberry cultivars. HortScience 37(2):386 389. https://doi.org/10.21273/HORTSCI.37.2.386 Fang, Y., Nunez, G. H., Fisher, P., Munoz, P. R. 2022. Effect of container size, substrate composition, and genotype on growth and fruit quality of young south ern highbush blueberry in a container-based inten sive production system. Sci. Hort. 302, p. 111149. https://doi.org/10.1016/j.scienta.2022.111149 Gaiotti, F., Pastore, C., Filippetti, I., Lovat, L., Bel fiore, N., Tomasi, D. 2018. Low night temperature at veraison enhances the accumulation of anthocya nins in Corvina grapes ( Vitis Vinifera L.). Sci Rep 8, 8719. https://doi.org/10.1038/s41598-018-26921-4 Li, Q., Yu, P., Lai, J., Gu, M. 2021. Micropropagation of the potential blueberry rootstock - Vaccinium arboreum through axillary shoot proliferation. Sci. Hort. 280, p. 109908. https://doi.org/10.1016/j.sci enta.2021.109908 Lyrene, P.M. 1997. Value of various taxa in breed ing tetraploid blueberries in Florida. Euphytica 94, 15–22. https://doi.org/10.1023/A:1002903609446 Menzel, C.M. Effect of temperature on soluble sol ids content in strawberry in Queensland, Australia. 2022. Horticulturae. 8, 367. https://doi.org/10.3390/ horticulturae8050367 Munoz, P. 2016. Blueberry Breeding Program. Patre cia: General description. https://www.blueberry breeding.com/patrecia [accessed 25 Aug 2022]. Nunez, G.H., Olmstead, J.W. Darnell, R.L. 2015. Rhi zosphere acidification is not part of