Evaluation of New Hybrid Cranberry Cultivars with Improved Fruit Quality, Yield and Disease Resistance

Progress report for ONE20-374

Project Type: Partnership
Funds awarded in 2020: $24,828.00
Projected End Date: 10/31/2023
Grant Recipient: University of Massachusetts
Region: Northeast
State: Massachusetts
Project Leader:
Dr. Giverson Mupambi
University of Massachusetts
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Project Information


Cranberry growers in Massachusetts (MA) are still mostly reliant on old cultivars, some of these cultivars like ‘Howes’ and ‘Early Black’ comprising 43.33% of total acreage have been cultivated by growers since 1843 and 1852 respectively. These cultivars have low productivity and are prone to diseases such as fruit rot. Additionally, MA does not have a breeding program for new cultivars. Growers in MA are interested in bringing in new hybrid cultivars from breeding programs in New Jersey and Wisconsin. However, without proper cultivar evaluation under MA growing conditions, growers are hesitant to do so because of the significant financial risk. The cost of renovating a cranberry bog is $10,000 to $25,000 per acre, and growers stand to lose out a lot when they ‘experiment’ with these new cultivars without proper evaluation.  This project, conducted in conjunction with a partner farmer, will evaluate new hybrid cultivars under MA growing conditions and provide growers with reliable data to use in the decision making process when considering bog renovation. The partner farmer will renovate a cranberry bog to be used as a test plot. Twelve new hybrid cultivars from breeding programs will be evaluated under rigorous scientific conditions. The experimental design will be a randomized complete block design with four replications per treatment. The data generated from the project will be disseminated to cranberry growers and other interested stakeholders through on-site field days, grower meetings, social media, the UMass Cranberry station website, peer-reviewed extension manuals, and research journals.

Project Objectives:

The project seeks to evaluate twelve new hybrid cranberry cultivars with improved fruit quality, yield, and disease resistance.  Data will be collected on yield, fruit quality, ease of establishment, and disease resistance. The questions we will answer are:

  1. Do the new hybrid cultivars outperform the cultivars currently grown in MA in terms of yield?
  2. Do the new hybrid cultivars have better fruit quality (fruit color, fruit firmness, internal quality, berry size) compared to the cultivars currently grown in MA in terms of yield?
  3. Do the new hybrid cultivars have a lower incidence of fruit rot and other diseases compared to the cultivars currently grown in MA?
  4. Do the new cultivars establish quickly (grow into all the available space) and come into full production earlier than the cultivars currently grown in MA?
  5. Do these new cultivars outcompete weed species found in MA, or do they need extra care in terms of weed control?

The project will benefit cranberry growers in MA by providing reliable information on yield performance, disease susceptibility and fruit quality of new hybrid cultivars under MA growing conditions. Growers will then be able to make informed choices when renovating their cranberry bogs. 


The majority of cranberry acreage in MA is still under old cultivars with low productivity and poor disease resistance.  The data in Table 1 represents the percentages of acreage of cultivars grown in MA as of 2017.  


Table 1: Percentages of acreage and the five-year average yield of cranberry cultivars grown in MA as of 2017.  The data was sourced from Ocean Spray and does not represent independent cranberry growers. Ocean Spray is a grower cooperative that represents 8,000 of the 13,000 acres under cranberry production in MA.


% of acreage

Commercial release

5 yr. yield avg. in MA (barrels/acre)









‘Early Black’




‘Ben Lear’




‘Mullica Queen®’




‘Crimson Queen®’








Unknown cultivars




Mixed cultivars




‘Grygleski 1’
















‘Scarlet Knight®’




n/a  - not available

The data shows that over 43.33 % of the acreage is still under the native cultivars ‘Early Black’ and ‘Howes’ “released” in 1852 and 1843 respectively. ‘Stevens’ and ‘Ben Lear’, which are the first generation of hybrid cultivars released in 1940 and 1900 respectively make up 39.74% of the acreage under cranberry production. Although ‘Stevens’ and ‘Ben Lear’ have higher yields, they were not specifically bred for disease resistance. Recently, disease resistance has become a desirable trait in cranberry production because of increased use restrictions on chlorothalonil which is a multisite inhibitor contact fungicide that is standard for fruit rot control (Wells et al., 2014). MA does not have an active cranberry breeding program, growers interested in new cultivars have to bring in new hybrids from the breeding programs in New Jersey and Wisconsin. However, since these new cultivars are not evaluated under MA growing conditions, they represent a substantial financial risk for growers.  The cost of renovating a cranberry bog is $10,000 to $25,000 per acre. Considering all these factors, the MA cranberry industry should plant new hybrid cranberry cultivars with improved fruit quality, yield, and disease resistance when renovating. Improved fruit quality and yields will increase profitability for farmers and improved disease resistance will lower environmental and health risks in agriculture through reduced pesticide usage. Our solution is to conduct a trial of the latest commercially released cranberry hybrid cultivars with a partner farmer under MA growing conditions and collect data on cultivar performance so that our growers can make better financial decisions.   Data will be collected on yield, disease incidence and ease of establishment. The experimental plots will also be made accessible to cranberry growers on field days, and growers will be able to walk through the demonstration plots.   Data collected can be used by cranberry growers in MA when making decisions for renovating their bogs, lowering their financial risk of planting untested hybrid cranberry cultivars.


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Materials and methods:
  1. Establishment of cultivar trial

The project will be carried out on a ≈0.9-acre commercial cranberry bog at Mann Farms in East Wareham, MA (Latitude: 41.7748115; Longitude -70.6208475). The bog will be renovated in the winter of 2020/21 by applying 10 inches of sand to the existing planting. Drainage tiles and sprinkler irrigation system will be installed during bog renovation. The twelve hybrid cranberry cultivars to be evaluated are listed in Table 2.   

Table 2: List of cultivars to be evaluated in the project.

Cultivar Name:

Commercial release 

Summary of key attributes

'Ruby Star®'


-Very strong yearly growth, strong bud sets, consistently high fruit yields



-Large berry size, excellent bud set traits, high yield potential, fertilizer tolerance, can be scaled up to full production relatively quickly



-Contains significantly higher red pigment, short seasonal maturity reduces the risk of crop damage due to unpredictable late-season weather events, excellent vigor, the yield is comparable to other commercial varieties.

'Crimson King'*


-Highest yielding, high color throughout the canopy

'Valley King'*


-High yield, very large fruit

'Pilgrim King'*


-Extremely large fruit, uniform color, high yield

'Midnight 8'*


-High yield, very early color, excellent rebud          

'Granite Red'*


-Extremely firm fruit, excellent fresh fruit keeping quality, large fruit with uniform color



-High yield potential, mid-season ripening, large round berry (averaging about two grams per berry) and uniform fruit color



-High yields with early to mid-season ripening

'Scarlet Knight®'


-Early ripening to a dark red, uniform color, lower titratable acidity, good keeping and storage properties



-high yield, improved disease resistance, and good fruit color

*There cultivars are not registered trademarks

-This list is not final and is subject to change pending additional consultations with cranberry growers and industry stakeholders over the summer.

-Efforts are being made to obtain more disease-resistant cultivars which are in final stages before commercial release at Philip E. Marucci Center for Blueberry and Cranberry Research and Extension in New Jersey.

Two cultivars, 'Stevens' and 'Mullica Queen®' will be used as the standard controls. 'Stevens' is the most widely grown cultivar in MA (Table 1) and 'Mullica Queen®' is a newer cultivar from New Jersey that does well in MA with the highest yields (Table 1). The experimental design will be a randomized complete block design with four plot replicates for each cultivar. Each plot replicate will be ≈ 40 feet long, and 15 feet wide with 2 feet buffer rows left in between. Cranberry vines will be sourced in December 2020 from the different breeding programs. The vines will be stored in a cooler at the UMass Cranberry Station and propagated as cuttings in a greenhouse at the UMass Cranberry Station. Standard commercial greenhouse guidelines will be followed during propagation. The rooted cuttings will be planted on the bog starting May 2021. After planting, standard cultural practices will be followed for fertilization, weed management, and irrigation.

  1. Data collection:

Year 1: In Year 1, data collection aims to classify the ease of establishment of each hybrid cultivar and susceptibility to diseases. Data on light interception will be collected using a ceptometer to measure how easily the new cultivars grow under MA growing conditions. Disease resistance will be scored visually by looking at the severity of any symptoms that may appear. Samples will also be collected for pathogen identification in the lab using plating methods.

Year 2:  In Year 2, the bog will be flooded in spring to kill off all the flowers. This will stop fruit formation, and all the resources in the vines can be devoted to vegetative growth. By doing so, the new cultivars are expected to be fully established by the end of Year 2. Data collection in Year 2 will be similar to Year 1, focusing on the ease of establishment of each cultivar and susceptibility to diseases.

Year 3: Intensive data collection will start in Year 3. This will be the first year of production. During the spring, data will be collected on bloom phenology by counting the number of flowers on the fruiting uprights. Ten fruiting uprights will be tagged in each plot replicate for all the cultivars. The total number of flowers will be assessed as well as the length of the flowering period. The ratio of flowering to vegetative growth will also be determined by collecting biomass samples using a 6-inch ring in each plot replicate for all the cultivars, separating the uprights into different classes, and then counting them. Starting eight weeks before commercial harvest (≈ mid-August), fruit samples will be collected for maturity indexing. The samples will be collected using a square foot quadrant in each plot replicate. The sample from each plot replicate will be weighed to estimate yield. A sub-sample of 25 fruit will be collected to measure fruit length, fruit diameter and fruit firmness using a FirmTech Fruit Firmness Tester®. The rest of the sample will be divided into two. Half the sample will be tested for fruit color development using the standard total anthocyanin test. The other half will be used to measure total soluble solids and titratable acidity. At commercial harvest, two square foot quadrants will be collected from each plot replicate for a more accurate estimate of yield potential. The samples collected at commercial harvest will also be assessed for fruit rot incidence in addition to the other tests described above.

Year 4 - Year 7: Although these years fall outside the timeline on this project, data collection will continue until Year 7. Full production is expected to be in Year 5, and yield data collected over several years may indicate trends like the susceptibly of the new cultivars to alternate bearing. Therefore, it is essential that data collection continues past the duration of project funding.

Data collected will be analyzed using one way ANOVA for significant differences between cultivars.

Progress ending 12/31/2020:

  1. Material Transfer Agreements (MTA)
    1. On the 14th of September 2020, we signed a standard MTA for the transfer of biological materials with the Wisconsin Alumni Research Foundation for the transfer of Ruby Star®, Sundance® and Hyred®.
    2. On the 21st of September 2020, we signed a standard MTA for the transfer of biological materials with Valley Corporation for the transfer of Crimson King, Valley King, Pilgrim King, Midnight 8, and Granite Red.
    3. As of December 2020, the MTA with Rutgers University was still outstanding. An issue arose pertaining to the sale of berries after samples have been collected. The problem was resolved, and the MTA is expected to be signed during the next reporting period.
  2. Propagation material
    1. In December 2020, we received the propagation material from Cranberry Creek Cranberries (representing the Wisconsin Alumni Research Foundation) and Valley Corporation. Valley Corporation replaced Valley King variety with Badger. They felt the latter was more suited to MA growing conditions. 
    2. The propagation material was stored in a walk-in cold room at 45°F and 100% relative humidity.

Progress ending 12/31/2021.

Propagation of the rooted cuttings began in early March in the greenhouse and continued until April. At the same time in March, the renovation of Section 1 of State Bog (≈0.75 acres)  at the UMass Cranberry Station was initiated. Initially, the project was going to be conducted at a grower collaborators' site. Unfortunately, because of some of the conditions that were imposed by one of the breeding programs, the location had to be shifted to the UMass Cranberry Station. The grower collaborator is still involved in the project, with regular meetings being held to discuss the progress of the project. The grower collaborator has also visited the new planting for an on-site meeting. The renovation included stripping off the top 10 inches of the bog and replacing it with new sand. A new irrigation and drainage system was also installed. The planting of the new cultivars started at the beginning of June and was finished by the end of June. The new cultivars were irrigated twice daily for 30 mins each, following guidelines for new cranberry plantings. The rooted plugs were planted at the industry standard 1-foot spacing. At planting, 50 lbs/A nitrogen and 100 lbs/A phosphorous were applied to the new planting following recommendations for new planting. After the roots were established, 10lbs nitrogen was applied every two weeks until mid-August. The new vines were successfully established with high colonization rates at the end of the growing season. At the end of the growing season in September, aerial imaging was done using a drone to quantify the establishment of the vines. The data is still being analyzed.

Progress ending 12/13/2022

To enable the evaluation of varietal performance under Massachusetts conditions, the following activities were carried out during the current reporting period (1) data collection with drones, (2) collecting vegetative samples for nutrient assessment, (3) preliminary fruit quality assessment (color and rot) (4) assessment of weed infestations (5) assessment of insect damage.

Data was collected using drones with red-green-blue (RGB) and multispectral cameras. The data images collected using drones were stitched together, and maps were created to evaluate the (1) establishment rate of the new cultivars and (2) health of the new cultivars using vegetation indices such as normalized difference vegetation index (NDVI). They were clear differences in establishment rates based on drone data (Figure 1).  The top performing cultivars in terms of canopy establishment were RU 4, VC 1, and VC 3.  The same trend applied to canopy health with clear differences observed between cultivars(Figure 2).

Fertilizer applications at the study site were managed as per current UMCS recommendations for new plantings. At the end of the growing season, samples were collected and sent for nutrient assessment to determine the response of the different cultivars to fertilizer application as per current guidelines. The results from plant tissue analysis are still being analyzed and will be used to adjust fertilizer recommendations for the coming growing season. 

Fruit samples were collected at 2-week intervals for assessment of fruit color (Figure 3). The samples were stored in the freezer and will be used to assess fruit color using the total anthocyanin method (we had no access to the labs because of building renovations).

Weed infestations at the study site were managed as per current UMCS recommendations for new plantings of cranberry vines. Growers strive to maximize cranberry vines colonization in Years 1-3 by minimizing weed infestations. Weeds in new cranberry plantings are managed with the use of pre-emergence and postemergence herbicides and hand weeding. The following herbicides were applied to the study site in 2022: Devrinol 2XT (napropamide) at 9 qt/A on 20 May and 29 June; Callisto (mesotrione) at 8 oz/A on 6 June, and Intensity One (clethodim) at 16 oz/A on 6 June and 8 July. Periodic hand-weeding was performed as needed throughout the season. The most common weeds in the study site were soft rush (Juncus effusus), haircap moss (Polytrichum spp.), crabgrass (Digitaria sanguinalis), and orange grass (Hypericum gentianoides). No insect damage was observed during the reporting period on the test plots

As of the 2022 growing season, as the canopy/planting is still establishing, we did not specifically observe any particular cultivar highly resistant or susceptible to diseases. In 2023, we will monitor closely for fruit rot and other diseases (Phytophthora root rot, Upright dieback) of commercial importance in Massachusetts.

Research results and discussion:

 Figure 1
Evaluation of canopy establishment
Evaluation of canopy health
Differences in canopy health as evaluated as observed by data collected with a multispectral drone.
Samples for fruit color anlaysis
Differences in fruit color between cultivars collected on 09-16-2022

Research conclusions:

Multiple of seasons of data are still needed in order to draw conclusions on the performance of the new cultivars. 

Participation Summary
2 Farmers participating in research

Education & Outreach Activities and Participation Summary

1 Published press articles, newsletters
2 Webinars / talks / presentations

Participation Summary:

238 Farmers participated
Education/outreach description:

The UMass Cranberry Station has a well-established and robust extension support network in addition to the institutional capacity to disseminate the project’s results. The Cranberry Station has an “open door” philosophy that facilitates communication between the researchers, cranberry growers, and industry personnel. Educational materials will be developed and shared via different avenues.  The different ways to share educational materials will include posters, fact sheets, Cranberry Station’s monthly newsletters, Cape Cod Cranberry Growers’ Association’s newsletter, online UMass ScholarWorks (digital library repository) and social media. The results from the project will also be disseminated to the broad network of cranberry growers and industry stakeholders through our annual workshops, field days, and extension outreach meetings. Annual webinars will be hosted to reach growers from other cranberry production areas that cannot physically attend our workshops and field days. The webinars will be posted on the Cranberry Station YouTube channel for future access. Results will also be communicated to the international cranberry research community at North American Cranberry Research and Extension Workers (NACREW) biennial meeting in 2023. At the end of the project, we will prepare manuscripts for publication in a peer-reviewed journal.

Progress ending 12/31/2021.

The Covid19 pandemic impacted certain extension outreach activities such as on-farm workshops/ field days, resulting in no in-person gatherings.  That being said, extension outreach was carried out in other virtual meetings, a newsletter article, and social media as listed below. 

  1.  An overview of the project was presented to 178 Massachusetts cranberry growers during the virtual annual research update
    meeting. 2021 Update Mtg_ Evaluation of New Hybrid Varieties with Improved
  2.  The progress of the project was shared in a newsletter disseminated to cranberry growers and stakeholders in
    Massachusetts (238 subscribers). CRANBERRY STATION NEWSLETTER
  3.   The progress report was shared during the annual Cranberry Station Board of Oversight meeting. Mupambi G New Hybrids 2021
  4.   A social media post about the project was shared on LinkedIn with 1364 views of the post in the feed.

Progress ending 12/31/2022.

  1. The progress of the new trial
  2. An overview of the project was presented to 160 Massachusetts cranberry growers during the virtual annual research update meeting. 2022 Update Mtg Jan 27: Update on New Variety Evaluations and PGR Trials

Learning Outcomes

178 Farmers reported changes in knowledge, attitudes, skills and/or awareness as a result of their participation
Key areas in which farmers reported changes in knowledge, attitude, skills and/or awareness:

Massachusetts cranberry growers gained awareness of new selections of varieties available from breeding programs in New Jersey and Wisconsin. 

Project Outcomes

1 Grant applied for that built upon this project
1 Grant received that built upon this project
$89,400.00 Dollar amount of grant received that built upon this project
2 New working collaborations

Information Products

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.