Rootstocks are commonly used in tree fruit production and, more recently, vegetable production systems (Djidonou et al., 2017; Zhao et al., 2018). However, the use of rootstocks in berry crops (strawberry, blackberry, raspberry, and blueberry) has not been commonly adopted. Rootstocks offer many advantages to crops, including size control (Basile and DeJong, 2018), increased yields (Xu et al., 2014), increased tolerance to biotic and abiotic stress (Liu et al., 2014), and enhanced soil adaptation (Penella et al., 2015).
Cultivated blueberry (Vaccinium species) have strict soil requirements for optimum growth. These include low pH (4.0–5.5), high organic matter, good aeration and drainage (Williamson et al., 2018), and readily available iron and ammonium (Darnell and Hiss, 2006; Nunez et al., 2015). As a result of these requirements, soil amendments and other modifications (e.g., sulfur applications) are used to increase organic matter, lower pH, and increase iron and ammonium availability. In the southeastern United States, pine bark is the common soil amendment used to increase soil organic matter and is typically incorporated into the top soil layer (Williamson et al., 2018). Without soil amendments, blueberry growth and yields decrease, and plants become chlorotic and nonproductive. However, soil amendments required for establishment and maintenance of blueberry plantings are costly (Julian et al., 2012) and may not be sustainable in the long term.
Vaccinium arboreum is a wild blueberry native to the southeastern United States. It is a single-trunk, small tree that is adapted to low-organic matter mineral soils. Furthermore, this species tolerates soil pH up to 6.5 and—contrary to cultivated Vaccinium—can assimilate nitrogen in the nitrate form (Darnell and Hiss, 2006), which is the predominant nitrogen form at higher pH. Because of the broader soil adaptation of V. arboreum compared with cultivated Vaccinium species, studies have examined the use of V. arboreum as a rootstock to increase soil adaptability of commercial blueberry production. Ballington (1996, 1998) found that grafting rabbiteye blueberry (V. virgatum) onto V. arboreum rootstocks increased plant growth and yield compared with own-rooted plants. More recently, Casamali et al. (2016) reported that SHB (V. corymbosum interspecific hybrid) grafted onto V. arboreum had increased yields compared with own-rooted plants when grown on nonamended soil, and similar yields compared with own-rooted plants on amended soil during the first 2 years of production. Thus, the use of V. arboreum as a rootstock for grafted SHB cultivars has the potential to decrease the use of pine bark (or other soil amendments) needed for optimal blueberry production, expand production areas to different soil types, and increase sustainability.
Although results from short-term research trials indicate the potential of using V. arboreum as a rootstock for blueberry, data from longer term trials are still needed. The current research continues the work initiated by Casamali et al. (2016) and examines the use of V. arboreum as a rootstock for SHB during 4 years after the establishment period. The hypothesis tested in the current research is that SHB grafted onto V. arboreum rootstocks have increased growth and yield compared with own-rooted SHB in both pine bark-amended and nonamended soils. The objectives were to evaluate the effects of soil treatment (amended vs. nonamended) and root system (own-rooted vs. grafted onto V. arboreum) on canopy growth, yield, berry weight, and berry quality in two cultivars of SHB. In addition, during the course of the experiment, root system differences in susceptibility to bacterial leaf scorch (Xylella fastidiosa) were observed; thus, incidence and severity of this disease were also evaluated.
Ballington, J.R. 1996 Performance of own-rooted ‘Premier’ rabbiteye blueberry vs. ‘Premier’ grafted on V. arboreum through three harvest seasons on a Fuquay soil HortScience 31 749 750
Ballington, J.R. 1998 Performance of own-rooted ‘Premier’ rabbiteye blueberry (Vaccinium ashei Reade) compared to ‘Premier’ grafted on Vaccinium arboreum Marsh (Sparkleberry) through four harvest seasons. Proceedings of the 8th North American Blueberry Research and Extension Workers Conference. p. 178–181
Brannen, P., Krewer, G., Boland, B., Horton, D. & Chang, C.J. 2016 Bacterial leaf scorch of blueberry. Circular 922. <https://extension.uga.edu/publications/detail.html?number=C922&title=Bacterial%20Leaf%20Scorch%20of%20Blueberry>
Casamali, B., Darnell, R. L., Kovaleski, A.P., Olmstead, J.W. & Williamson, J.G. 2016 Vegetative and reproductive traits of two southern highbush blueberry cultivars grafted onto Vaccinium arboreum rootstocks HortScience 51 880 886
Darnell, R.L. & Hiss, S.A. 2006 Uptake and assimilation of nitrate and iron in two Vaccinium species as affected by external nitrate concentration J. Amer. Soc. Hort. Sci. 131 5 10
Djidonou, D., Zhao, X., Brecht, J.K. & Cordasco, K.M. 2017 Influence of interspecific hybrid rootstocks on tomato growth, nutrient accumulation, yield, and fruit composition under greenhouse conditions HortTechnology 27 868 877
Ehlenfeldt, M.K. & Martin, R.B. 2002 A survey of fruit firmness in highbush blueberry and species-introgressed blueberry cultivars HortScience 37 386 389
Galletta, G.J. & Fish, A.S. Jr 1971 Interspecific blueberry grafting, a way to extend Vaccinium culture to different soils J. Amer. Soc. Hort. Sci. 96 294 298
Harmon, P. & Hopkins, D. 2009 First report of bacterial leaf scorch caused by Xylella fastidiosa on southern highbush blueberry in Florida Plant Dis. 93 1220
Julian, J.W., Strik, B.C., Larco, H.O., Bryla, D.R. & Sullivan, D.M. 2012 Costs of establishing organic northern highbush blueberry: Impact of planting method, fertilization, and mulch type HortScience 47 866 873
Kunitake, H., Tsuda, H., Takagi, R., Ohno, Y., Kurori, Y., Yoshioka, K., Kage, T., Ito, T. & Komatsu, H. 2006 Possibility of wild blueberry Shashanbo (Vaccinium bracteatum Thunb.) as rootstock for cultivation of northern highbush blueberry in warm region Engeigaku Kenkyuu 5 105 110
Liu, J., Li, J., Su, X. & Xia, Z. 2014 Grafting improves drought tolerance by regulating anti-oxidant enzymes activities and stress-responsive gene expression in tobacco Environ. Exp. Bot. 107 173 179
Lyrene, P.M. 2008 Southern highbush blueberry plant named ‘Farthing’. Patent PP19341. 14 Oct. 2008
Lyrene, P.M. 2010 Southern highbush blueberry plant named ‘FL01-173’. U.S. Patent 21553. 7 Dec. 2010
Nunez, G.H., Olmstead, J.W. & Darnell, R.L. 2015 Rhizosphere acidification is not part of the strategy I iron deficiency response of Vaccinium arboreum and the southern highbush blueberry HortScience 50 1064 1069
Penella, C., Nebauer, S.G., Quinones, A., San Bautista, A., Lopez-Galarza, S. & Calatayud, A. 2015 Some rootstocks improve pepper tolerance to mild salinity through ionic regulation Plant Sci. 2390 12 22
Williamson, J.G., Olmstead, J.W., England, G.K. & Lyrene, P.M. 2014 Southern highbush blueberry cultivars from the University of Florida. Univ. Fla. Coop. Ext. Serv., HS 1245
Williamson, J.G., Olmstead, J.W. & Lyrene, P.M. 2018 Florida’s commercial blueberry industry. Univ. Fla. Coop. Ext. Serv., HS 742
Xu, C., Ma, Y. & Chen, H. 2014 Technique of grafting with Wufanshu (Vaccinium bracteatum Thunb.) and the effects on blueberry plant growth and development, fruit yield and quality Scientia Hort. 176 290 296
Zhao, X., Liu, Q., Sanchez, M.T. & Dufault, N.S. 2018 Performance of grafted seedless watermelon plants with and without root excision under inoculation with Fusarium oxysporum f.sp. niveum race 2 HortScience 53 1340 1346