‘Honeycrisp’ is a popular new apple cultivar in the premium fresh-fruit marketplace (Rosenberger et al., 2004). Because of the high returns for ‘Honeycrisp’ in the North American markets, Nova Scotia growers are interested in learning how to efficiently manage this cultivar in their region (Nichols and Wright, 2003). The cultivar is hardy and responds well to the more northerly climates (Luby and Bedford, 1990). Although developed in Minnesota and described as a good annual cropper requiring no flower thinning, ‘Honeycrisp’ has exhibited an extreme propensity for overcropping resulting in biennial bearing (Crassweller et al., 2005; Embree and Nichols, 2005; Robinson and Watkins, 2003).
Biennial bearing is the tendency of a cultivar to cycle between a full (“on”) crop year and a minimal (“off”) crop year resulting in inconsistent fruit quality and quantity (Monselise and Goldschmidt, 1982). Biennial bearing can be controlled to some extent by managing crop load in the “on” year, but results vary with cultivar (Schwallier et al., 2006; Singh, 1948). Research has shown that blossom thinning is more effective than fruitlet thinning alone to increase the potential for return bloom (Byers, 1997; Johnson, 1995; Preston, 1954; Singh, 1948; Tromp, 2000), stimulate tree growth, and increase fruit size (McArtney et al., 1996). For many cultivars, the optimal crop load is between 5 and 6 fruit/cm−2 trunk cross-sectional area (TSCA) (Robinson and Watkins, 2003), but this varies with cultivar and depends on many factors, including spur habit and tree vigor (Singh, 1948).
Managing blossom density and crop load to control the strong biennial nature of this cultivar is one of the greatest challenges for ‘Honeycrisp’ producers. To meet this challenge, we evaluated the impact of adjusting blossom density and subsequent crop load on growth, fruit quality, and return bloom.
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Crassweller, R. McNew, R. Azarenko, A. Barrit, B. Belding, R. Berkett, L. Brown, S. Clemens, J. Cline, J. Cowgill, W. Ferree, D. Garcia, E. Greene, D. Greene, G. Hampson, C. Merwin, I. Miller, D. Miller, S. Moran, R. Obermiller, J. Rosenberger, D. Rom, T. Roper, T. Schupp, J. Stover, E. 2005 Performance of apple cultivars in the 1995 NE-183 regional project planting: I. Growth and yield characteristicsJournal for the American Pomological Society 59 18 27
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