Trials Field Day Results Summary

September 15, 2014

Our 2014 cucumber, melon and winter squash trials are funded by a one year SARE grant. Primary goals are to evaluate resistance to Cucurbit Downy Mildew, and to identify resistant seedstocks. We are also looking at eating quality and productivity. Downy Mildew has been the number one limiting factor in cucurbit production on our farm, affecting seed crops as well as market crops of cucumber, squash, melon, gourd and watermelon. We want to find varieties that will do better, and to share the results. Some of what we find will be useful as is, and some will be useful in future breeding projects. Another part of our SARE project is a grower survey about cucurbit seed needs. This will be useful in planning future trials and breeding projects. Please consider taking the survey!   tinyurl.com/cucurbitsurvey

 

Basic Methods:

Our trials include three replications of most entries, plus some single entries. Each entry has five plants. We made an effort to promote uniform field conditions. Each of the trials are planted in a space that had a single crop last year. Fertility inputs were applied carefully and evenly. The trials are surrounded by border plantings to avoid “edge effect,” in which edge plantings perform better or worse than the rest of the trial.

Michael Mazourek from Cornell’s Department of Plant Breeding helped us design the trials. His program focuses on breeding vegetables for organic growing conditions, and has produced several Downy Mildew resistant varieties. They are very accessible and fun to work with. We also consulted with Organic Seed Alliance and used their publication “On-farm Variety Trials: A Guide for Organic Vegetable, Herb, and Flower Producers.” This is a great resource and inspiration that can be found for free online. Cornell and OSA will also be helping with data analysis.

 

Winter Squash Trial:

-20 replicated entries, plus 25 single entries.

-12 foot row spacing, 2 feet between plants and 12 feet in-row between entries.

-Fertilized with tofu okara at 4 tons per acre; compost at 2 tons per acre (side dressed); potassium sulfate and magnesium sulfate at 200 pounds per acre each (side dressed); previous crop was grass hay.

-Planting date (direct seeding) was June 10th for most entries, with a May 20th planting date for the Caribbean tropical pumpkins. We planted late to maximize Downy Mildew exposure.

-We had to train the vines every few days all summer!

-Most of the entries are Cucurbita Moschata species. Many are tropical pumpkins, including from Puerto Rico, Cuba, Jamaica, Panama, China, India, Costa Rica and Thailand. Several varieties are from the Southeast US.

-Controls are Waltham butternut and Johnny’s 6823 PMR butternut.

-Downy mildew has been the primary disease in the trial, but the C. Maxima varieties have also experienced significant bacterial wilt and damage from vine borers. Powdery mildew has been present to a slight degree, except on the Acorn squash where there was heavy incidence. We have recorded weekly disease incidence ratings since August 22nd.

What we’ve found so far:   Just about everything is more DM resistant than Waltham butternut, which had almost complete dieback by August 22, 73 days after planting. Many of the tropical pumpkins are especially resistant.

There was good fruit set on the Waltham, and I am not clear about whether fruits are mature enough to be marketable – I think they are, but not of optimal quality. Fruits are mostly sweet but seeds are not mature. An early-planted Waltham crop would have had plenty of time this year to produce well before DM got bad. In 2013 however, we experienced near crop failure with early planted Waltham due to DM, which arrived earlier in 2013 than in 2014.

Yield measurements, brix readings, tasting, dry matter measurement, and assessment of fruit maturity are important parts of the evaluation that haven’t happened yet.

One important question involves the relationship between productivity and disease. Some of the varieties may have low disease incidence because they’re not putting as much energy into making fruit. To some extent, Waltham may have the opposite tendency.

A goal of this project is to find a more DM resistant butternut than the controls. There are four entries that may meet or partially meet this goal, though they aren’t as resistant as the tropical pumpkins. Greek Sweet Red, Pequenia Asar, Seminole-Waltham Cross (F3) and Butterbush Offtype, a selection from Burpee’s Butterbush.

Most of the Maxima squashes experienced a lot of Bacterial Wilt and vine borer damage. Candy Roaster Melon appears to be somewhat less affected, and Arka Surimata (India) appears unaffected.

 

Cucumber Trial

-35 replicated entries and 23 single entries.

-6 foot row spacing; 1 foot between plants and five feet between entries in-row.

-Provided Nitrogen with early cowpea cover crop, supplemented by tofu okara side dressing at a rate of 1.75 tons per acre. Last year’s crop was sorghum-sudan cover crop.

-Planting date was June 27; transplant dates were July 12 and 13.

-We obtained many of the seedstocks from the USDA Plant Introduction Station in Ames, Iowa. This is a great resource. Most of the entries were chosen because they showed resistance in a previous test or because we otherwise suspected DM resistance. Many of the entries are Chinese trellising cucumbers.

-Downy Mildew pressure has been severe in the trial, and there has also been a lot of Bacterial Wilt. This combination will make the data somewhat more difficult to analyze. We have recorded weekly DM and BW foliage ratings since early August.

What we’ve found so far:   Most of the entries produced much better than the susceptible control, Straight Eights, with yields up to 25 times higher. Many varieties did better than the moderately resistant control, Marketmore 76, yielding up to 3.5 times more.

There is definitely a correlation between DM pressure and yield, though it is complicated by Bacterial Wilt incidence.

10 Chinese trellising cucumbers yielded well in the trial, as well as two Thai varieties, three varieties from India and one from the Philippines. Cornell’s breeding lines DMR-264 and DMR-261 did well, as did Ivory Queen.

There is an edge effect in the westernmost row, with yields disproportionately high. Prevailing winds blow spores from western rows to their eastern neighbors. The western row was bordered by melons, which seems to have been inadequate in this regard.

 

Melon Trial

-32 replicated entries and 4 single entries

-7 foot row spacing; 1.5 feet between plants; 6 feet between entries in-row

-Provided Nitrogen with early cowpea cover crop, supplemented by tofu okara side dressing at a rate of 1.75 tons per acre. Last year’s crop was sorghum-sudan cover crop.

-Planting date was June 13; transplant dates were June28 and 29.

-Controls were Delicious 51, Hale’s Best and Athena.

-Many of the seedstocks for the trial came from the USDA Plant Introduction Station in Ames, Iowa.

– Downy Mildew pressure was severe in this trial, as was Bacterial Wilt for some entries. Weekly disease ratings started on 8/11.

What we’ve found so far:  There were only a handful of varieties that were able to produce sweet fruits, and there appears to be good correlation between DM foliage ratings and brix readings. Seminole (average of 9.6 brix), Tai Nang (11.4 brix) and Trifecta (10.3 brix) stand out as the sweetest, followed by Hannah’s Choice (8.9 brix), Edisto 47 (8.4 brix), Sivan (8.3), Wrangler (8.1) and Athena (7.6). Almost all of the Seminole, Tai Nang and Trifecta melons tasted sweet, and the intermediate varieties had mixed sweetness. Hales Best averaged 5.6 brix; Delicious 51 averaged 6.8 brix.

Seminole had the best DM foliage ratings in the trial, followed by Tai Nang, Edisto 47, Trifecta, Hannah’s Choice, Wrangler, Sivan, Athena and 124112 (though 2 of 3 entries died from wilt).

Many of the unusual PI entries were very susceptible to Bacterial Wilt, and most were highly impacted by BW and/or DM.

Keeping up with the evaluations was challenging, and part way into the trial we decided to stop evaluating most of the entries that weren’t orange netted melons. Evaluating varieties that showed poor disease resistance and unusual eating qualities was difficult and did not seem valuable. This left 19 replicated entries and 3 single entries.

 

Please check back on our website for final results in about six weeks.

 

 

 

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One thought on “Trials Field Day Results Summary

  1. Pingback: Cucurbit Trial Field Day | Twin Oaks Seed Farm

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