‘T-1101’ Rabbiteye Blueberry Krewer™

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D. Scott NeSmith Department of Horticulture, University of Georgia-Griffin Campus, Griffin, GA 30223-1797

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Rabbiteye blueberry (Vaccinium virgatum Aiton; syn. Vaccinium ashei Reade) cultivars constitute a major portion of the blueberry acreage in Georgia and across much of the Southeast (Krewer and NeSmith, 2002; Scherm et al., 2001). The species is largely grown because of its high plant vigor and adaptability to the area. However, the small fruit size of most current rabbiteye blueberry cultivars often diminishes their potential to compete with larger fruited highbush (Vaccinium corymbosum L.) cultivars from other regions in the fresh market arena. Small berry size also results in poor efficiency with hand harvesting, which often destines much of the rabbiteye crop to being machine harvested and used for processing. Thus, commercial growers could reap immediate tangible benefits from larger fruited rabbiteye cultivars that improve hand-harvest efficiency. Concurrently, many small pick-your-own operations would greatly benefit from larger fruited cultivars to improve the overall “harvest experience” for their customers. We have been diligently seeking to develop larger fruited rabbiteye cultivars at The University of Georgia (UGA) for the past 20 years with hopes of alleviating some of these issues. NeSmith (2014) described the recently released Titan™ (patented as ‘T-959’, USPP 24,135), and a second large-fruited cultivar T-1101 (USPP 28,623) rabbiteye blueberry Krewer™ is being released. Together, the two cultivars offer growers of rabbiteye blueberries companion cultivars suitable for pollinating each other that also have large, compatible berry size.

Origin and Description

Krewer™, named in honor of retired UGA Blueberry Extension Specialist Dr. Gerard Krewer, was selected in 2007 at the Georgia Experiment Station in Griffin, GA, originated from a group of seedlings derived from open pollinated ‘Vernon’ fruit in 2004. The maternal parent, ‘Vernon’ (USPP 18,291), is a 2004 UGA release (NeSmith et al., 2005). Tested and patented as ‘T-1101’ (USPP 28,623), Krewer™ is being released for commercial usage, and for pick-your-own and homeowner markets. Krewer™ ripens around the time of the early rabbiteye cultivars Alapaha (USPP 16,266), Titan™, and Vernon (NeSmith, 2014; NeSmith et al., 2002, 2005). Krewer™ has very large (2.7–3.1 g), firm berries that are medium blue, with a medium size, dry picking scar. Plants are vigorous and semiupright, having shown very good adaptation to both the Coastal Plains and Piedmont Regions of Georgia. No notable disease or other pest problems have been observed for Krewer™ that have not also been common in other blueberry cultivars and selections in the vicinity of the test plots. Krewer™ is estimated to have a chilling requirement of 350–450 h below 7 °C based on observations and comparisons with other cultivars. Propagation is easily accomplished using either softwood cuttings or in vitro tissue culture production. Plants have low self-fertility like most rabbiteye cultivars; therefore, planting with other cultivars with a similar flowering time is recommended for cross-pollination.

Performance

Krewer™ was tested in UGA Research Farm plantings at Alapaha and Griffin, GA locations starting in Fall 2009. Tables 1 and 2 present multiyear fruit and plant data for Krewer™ and three commercial blueberry cultivars as standards at the two sites. Overall, numerical ratings indicate Krewer™ berry size was superior to that of ‘Alapaha’ and ‘Vernon’, being similar to the large-fruited Titan™ at both locations. The new cultivar generally ripens early in the season, along with ‘Alapaha’, ‘Vernon’, and Titan™, but tends to flower 5–7 d earlier than those cultivars.

Table 1.

Four-year average ratings of some fruit and plant characteristics of Krewer™ and rabbiteye standard cultivars Alapaha, Vernon, and Titan™ from 2011 to 2014 in field test plots at Alapaha, GA. Rating scales are based on a 1–10 score, with 1 being the least desirable and 10 being the most desirable. A value of 6 and 7 (except for cropping score) is generally considered to be the minimum acceptable rating for a commercial cultivar. These plants were established in Fall 2009.

Table 1.
Table 2.

Four-year average ratings of some fruit and plant characteristics of Krewer™ and rabbiteye standard cultivars Alapaha, Vernon, and Titan™ from 2011 to 2014 in field test plots at Griffin, GA. Rating scales are based on a 1 to 10 score, with 1 being the least desirable and 10 being the most desirable. A value of 6 and 7 (except for cropping score) is generally considered to be the minimum acceptable rating for a commercial cultivar. These plants were established in Fall 2009.

Table 2.

A detailed assessment of the berry attributes, weight, firmness, and Brix for Krewer™ and other cultivars during the 2012 and 2013 seasons is denoted in Table 3. Mean berry weight was obtained from three samples of 25 berries per cultivar; firmness was determined for three 25-berry samples using a FirmTech II device (Bioworks Inc., Wamego, KS); and Brix readings were determined from a subsample of five berries using a handheld refractometer (Extech Instruments, Boston, MA). Data were obtained from the first 25% to 30% of ripe fruit for each cultivar. Krewer™ had notably larger berries than ‘Alapaha’ and ‘Vernon’ each year. Firmness of Krewer™ was less than that of Titan™ each year, but better than those of ‘Alapaha’ and ‘Vernon’ in 2012. Brix readings were highest for Krewer™ in 2012 and for Krewer™ and ‘Alapaha’ in 2013.

Table 3.

Berry weight, firmness, and Brix for Krewer™ and standard cultivars Alapaha, Vernon, and Titan™ at Griffin, GA, during 2012 and 2013. These plants were established in 2009.

Table 3.

The total yield per plant was determined for three single plant replicates via multiple hand harvests in selection test plots at Alapaha, GA, in 2013 and 2014 for Krewer™ and ‘Vernon’ (Table 4). Mean berry weight was also determined from three 25-berry samples for each plant at each harvest. These data support that Krewer™ is also high yielding and further supported the new cultivar's tendency to produce large berry size.

Table 4.

Yield and berry weight for Krewer™ and ‘Vernon’ at Alapaha, GA, during 2013 and 2014. These plants were established in 2009.

Table 4.

With all of the positive attributes, Krewer™ does carry the negative characteristic of being slightly to moderately susceptible to fruit splitting. Fruit splitting is a physiological phenomenon, not completely understood, that occurs periodically for certain varieties after heavy rains that occur during fruit ripening (Marshall et al., 2007). Limited field observations indicate that, Krewer™ could encounter fruit splitting problems under certain conditions; however, Titan™ has been shown to be even more susceptible (NeSmith, 2014). Another less desirable trait for Krewer™ is that there can be some delay in the development of blue color over the entire berry. Those harvesting will need to let the fruit fully mature before harvest to avoid “pink backs” with the fruit. However, full color development does occur if the fruit is not harvested prematurely. Finally, early flowering could predispose Krewer™ to spring frost damage in some years at vulnerable locations.

In summary, ‘T-1101’ rabbiteye blueberry Krewer™ (Fig. 1) is large-fruited, with good firmness and Brix. A high degree of plant vigor, good yields, and an early ripening time are desirable features of this new cultivar. Krewer™ is somewhat susceptible to rain splitting; however, this potentially negative trait is outweighed by the benefits of the very large berry size and other positive attributes.

Fig. 1.
Fig. 1.

Fruit of ‘T-1101’ rabbiteye blueberry Krewer™ during ripening.

Citation: HortScience horts 53, 1; 10.21273/HORTSCI12704-17

Availability

Blueberry ‘T-1101’ (USPP 28,623) Krewer™ is owned by the University of Georgia Research Foundation. Propagation rights are controlled by the University of Georgia Research Foundation, Innovation Gateway, GSRC Boyd Bldg, Athens, GA 30602-7411 (http://research.uga.edu/gateway/).

Literature Cited

  • Krewer, G. & NeSmith, D.S. 2002 The Georgia blueberry industry: Its history, present state, and potential for development in the next decade Acta Hort. 574 101 106

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  • Marshall, D.A., Spiers, J.M., Curry, K.J. & Stringer, S.J. 2007 Laboratory method to estimate rain-induced splitting in cultivated blueberries HortScience 42 1551 1553

    • Search Google Scholar
    • Export Citation
  • NeSmith, D.S. 2014 ‘T-959’ rabbiteye blueberry Titan™ HortScience 49 672 673

  • NeSmith, D.S., Draper, A.D. & Spiers, J.M. 2002 ‘Alapaha’ rabbiteye blueberry HortScience 37 714 715

  • NeSmith, D.S., Draper, A.D. & Spiers, J.M. 2005 ‘Vernon’ rabbiteye blueberry HortScience 40 2200 2201

  • Scherm, H., NeSmith, D.S., Horton, D.L. & Krewer, G. 2001 A survey of horticultural and pest management practices of the Georgia blueberry industry Small Fruits Rev. 1 4 17 28

    • Search Google Scholar
    • Export Citation
  • Fruit of ‘T-1101’ rabbiteye blueberry Krewer™ during ripening.

  • Krewer, G. & NeSmith, D.S. 2002 The Georgia blueberry industry: Its history, present state, and potential for development in the next decade Acta Hort. 574 101 106

    • Search Google Scholar
    • Export Citation
  • Marshall, D.A., Spiers, J.M., Curry, K.J. & Stringer, S.J. 2007 Laboratory method to estimate rain-induced splitting in cultivated blueberries HortScience 42 1551 1553

    • Search Google Scholar
    • Export Citation
  • NeSmith, D.S. 2014 ‘T-959’ rabbiteye blueberry Titan™ HortScience 49 672 673

  • NeSmith, D.S., Draper, A.D. & Spiers, J.M. 2002 ‘Alapaha’ rabbiteye blueberry HortScience 37 714 715

  • NeSmith, D.S., Draper, A.D. & Spiers, J.M. 2005 ‘Vernon’ rabbiteye blueberry HortScience 40 2200 2201

  • Scherm, H., NeSmith, D.S., Horton, D.L. & Krewer, G. 2001 A survey of horticultural and pest management practices of the Georgia blueberry industry Small Fruits Rev. 1 4 17 28

    • Search Google Scholar
    • Export Citation
D. Scott NeSmith Department of Horticulture, University of Georgia-Griffin Campus, Griffin, GA 30223-1797

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Contributor Notes

A contribution of the University of Georgia Agricultural Experiment Station's Griffin Campus. This research was supported, in part, by state and Hatch Act funds allocated to the Georgia Agricultural Experiment Stations.

Professor.

Corresponding author. E-mail: snesmith@uga.edu.

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  • Fruit of ‘T-1101’ rabbiteye blueberry Krewer™ during ripening.

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