All posts by Thomas Björkman

A new resource for plant research

The plant research community has a valuable and practical new resource available: a rapid-cycling Brassica oleracea population that can be used to map the genetics of many traits simply by phenotyping. The population and related resources are described in a recent publication led by Zach Stansell in Thomas Björkman’s lab at Cornell University.

  • The map and reference genome are complete
  • Bioinformatic-analysis pipeline is available
  • Seed is available for free
  • Researchers only need to phenotype and analyze


The BolTBDH population is derived from a from a cross of rapid-cycling Chinese kale with broccoli. It is particularly valuable for studying reproductive development because progeny lines have inflorescences that range from non-heading to fully heading broccoli. Variation is documented for many other traits, such as architecture and glucosinolate content, and variation in many others remains to be explored and documented.

To1000 is a small plant with long inflorescences, Early Big is a normal broccoli
Parents of BolTBDH: the rapid-cycling Chinese kale, TO1000 and the broccoli ‘Early Big’.

Continue reading A new resource for plant research

Selecting subjective traits in multiple sites.

Zach Stansell has adapted his tool for breeders so that it is usable for any crop that has a highly subjective breeding goal.

Stansell with computer code
Zach Stansell has developed an R package that helps breeders assess their criteria for subjective traits like beauty in many locations.

We are sharing the information with various media outlets. The first pass is a publication in the Cornell Chronicle.

Many horticultural crops need to meet the quality criteria of a particular market or of the main breeder. They need to meet those criteria in many environments. How can you test for   quality  in many locations at the same time. This technique is good at predicting the reference person’s quality score by having trained raters make objective measurements.

The package is posted on GitHub so that anyone can use it for free. It is annotated and revised to work with just about any trait of interest or any crop. The revision was done with Deniz Akdemir, Cornell statistician. The development of the method is published in HortScience (Stansell, Zachary, Thomas Björkman, Sandra Branham, David Couillard, and Mark W. Farnham. 2017. Use of a Quality Trait Index to Increase the Reliability of Phenotypic Evaluations in Broccoli HortScience 32:1490-1495. doi: 10.21273/HORTSCI12202-17 )

 

Managing nitrogen timing in summer-harvested broccoli

Picture of tight and loose heads, with cross-section of the heads
Late nitrogen application can cause early side-branch elongation, making the heads less desirable on the market. The top image shows a tight head with solid side branches. The lower image has a head that has begun to loosen at the sides. This effect can be reduced by having the last nitrogen application at least four weeks before harvest so that the growth rate is slowing down a bit just as harvest begins.

One of the challenges with raising broccoli in the East is getting heads to stay dense. In the warmth of summer, the outer branches of broccoli tend to start elongating a little before harvest maturity. They “blow up” in the words of many producers. The result is a head that doesn’t pack tightly in the box and has soft edges that are prone to damage in handling.

The solution is to let growth slow a little during the week before harvest. Growth is promoted by the combination of warmth, water, nitrogen, and sunlight. Warmth is a given for harvests in July and early August, sunlight we have no control over, and abundant water sometimes comes whether we want it or not. The main management tool is nitrogen.

Slowing growth by reducing nitrogen is a considerable challenge because abundant nitrogen is needed during the vegetative growth to get strong, healthy, fast-growing plants. The best approach is to supply nitrogen relatively early in the growing period, and not add nitrogen in the last four weeks.

Many popular broccoli varieties are harvested starting only eight weeks after transplanting. Therefore, the last nitrogen application should be only four weeks after transplanting. At that time, the foliage is near full cover, which a good time for a traditional side-dress application as well as cultivation to get escaped or newly germinated weeds. Fertigation through a trickle-irrigation system would be during the fourth week. At that time, the plants are large enough to take up the nitrogen but not so far along that excess growth at harvest will cause loose heads.

Applying all of the nitrogen before planting is a possibility. Ordinarily, applying 120 to 150 pounds per acre of nitrogen preplant is ill-advised because of the high likelihood of leaching before the crop takes it all up. However, because broccoli is only in the ground for about nine weeks through the end of harvest, and reaches its maximum uptake five weeks after transplanting, the risk of leaching loss is relatively low compared to the typical situation. Pre-plant application of the fertilizer opens up production options that don’t allow side-dressing or liquid fertilization.

This early-nitrogen approach is also helpful in reducing hollow stem. Hollow stem is likewise a symptom of excessive late vegetative growth. The main tool for managing hollow stem is adjusting the plant population. If hollow stem is a problem, it’s likely that both yield and quality will be improved by spacing the plants closer together. In New York we have found an in-row spacing of 8 inches to work quite well. But limiting late nitrogen also tempers the growth rate at the right time.

This article was published in VegEdge on June 5, 2019. A publication of the CCE Cornell Vegetable Program.

Fresh broccoli from Mexico now plays an important role

The Eastern Broccoli Project is intended to supply some of the growth in broccoli consumption in the East. The bulk of supply comes from coastal California in the summer and the desert southwest in the winter. But now, imports from Mexico are playing a greater role.

When the project started in 2009, Mexico was not a significant supplier of fresh broccoli to the East. That has changed. The volume from Mexico to the US is over $200 million per year. The frozen market is almost entirely from Mexico and Central America.

Fresh wholesale value is up from $60 to 250 million. Frozen has risen from $250 to $350 million.
The total value of imported fresh broccoli has quadrupled over the past ten years. Current imports represents about one fourth of the total wholesale volume. That amount can put pressure on prices. Frozen has risen modestly.
The wholesale price has risen from $0.30 to $0.50 since 2008
The wholesale price of imported broccoli has been rising steadily.

Mexican imports primarily compete with winter production in Florida and Georgia. The volume in the winter months has been rising over the last five winters, more than the summer imports. Growers in those areas are also expressing concern about the effect of the USMCA trade deal, fearing that it would allow dumping in their market.

Eastern production is closer to the Northeast market than either Mexico or the desert, but it is significant. The distance to the terminal market in Bronx NY from Hastings, Florida is 1000 miles in 15h of driving.  From San Luis Potosi, Mexico is 2400 miles in 36 hours, and from Yuma, Arizona is 2600 miles in 39 h.

Demand peaks at 60 million pound in January and bottoms in July at 20 million pounds. is fairl
Winter is the peak of fresh broccoli imports, but there is significant volume all year. The quantity shipped in January and February has been increasing most.

 

Volume varies modestly between 40 and 60 million pounds with peaks in March and October
Frozen broccoli imports are fairly stable throughout the year, reflecting a continuous consumer demand.

There are some facilities to freeze broccoli in New York. Developing a frozen deal for New York growers would be needed for a customer like a school system that specified New York broccoli under the farm-to-school program, but needed ready-to use product in their kitchens during the school year. The frozen-food giant Bonduelle raises and freezes broccoli in Québec, so the economics can be made to work nearby.

Thanks to USDA-ERS economists Kamron Daugherty and Broderick Parr for compiling this important information.

More Eastern farms are raising broccoli according to 2017 Census of Agriculture

We have eagerly awaited the 2017 Census of Agriculture to see whether the Eastern Broccoli Project is having an effect. Today, the results were released, allowing us to compare our early effect (2017) with the pre-project baseline. We are happy to see so many more Eastern farms finding a place for broccoli in their crop mix.

State
2012
2017
Gain
Maine 145 273 88%
Vermont 87 111 28%
New Hampshire 61 116 90%
Massachusetts 135 243 80%
Rhode Island 25 27 8%
Connecticut 51 132 159%
New York 290 535 84%
Michigan 158 443 180%
Pennsylvania 245 522 113%
New Jersey 64 136 113%
Delaware 5 19 280%
West Virginia 23 95 313%
Maryland 44 76 73%
Virginia 105 221 110%
North Carolina 140 317 126%
Tennessee 28 142 407%
South Carolina 34 100 194%
Georgia 44 138 214%
Florida 76 168 121%

Fertilizing the broccoli orchard

We have good fertility recommendations for various areas in the East on the resources tab.

A recent Bizarro comic has a great reference to broccoli’s ability to use fertilizer.

Fertilizer makes broccoli grow big
(c) Dan Piraro Used by permission.

We are not in cahoots with the “National Board of Broccoli Producers,” so broccolini is a fair stand-in at the Eastern Broccoli Project.

Waist high broccoli in a field with black soil.
Broccoli on muck soil gets a lot of nitrogen and water, and can grow very tall. Retired Cornell broccoli researcher Joe Shail provides the scale.

One consideration is that broccoli can get too big, and get hollow stem. Growers harvesting in the heat of summer find that making the last nitrogen fertilization four weeks before harvest helps avoid the excessive burst.

Some early varieties are maturing in 50 days in the summer. If you do the math, that means the last nitrogen side dress or fertigation is just three weeks after transplanting. Putting on ~150 lb/ac of nitrogen without burning the plants takes some planning.

Quality standards for local broccoli

Excellent thesis work by Carol Jiayi Dong and Phil Coles was just published in the Journal of Food Distribution Research

Article title

The article, titled Produce Buyer Quality Requirements to Form an Eastern Broccoli Industry is available open access at JFDR.

The article show that wholesale buyers expect broccoli to look familiar. Local variants with slightly different color or flower-bud size were acceptable only to natural food reseller, not at standard supermarkets. The challenge for a new region is to meet standards that were developed for other production areas.

Carol is currently pursuing her PhD in ag economics at UC Davis, Phil is  a professor of practice in business at Lehigh University.

Webinar: Raising organic broccoli in the East

We invite interested eastern growers and distributors to participate.

Wednesday January 23, 12:00 – 1:00 pm EST

Introduction
Click here for the full recording. The hamburger menu on the video lets you move to specific sections of the webinar.

Eastern buyers are eager to source more Organic broccoli locally. Fortunately, broccoli is suited to Organic practices. Nevertheless, meeting that demand will require efficient production.

This webinar will cover management approaches for Organic production that help production efficiency. Prospective growers will come away with a better sense of how to achieve success, and current Organic broccoli growers are likely to pick up some useful ideas to increase their profitability.

Presenters

  • Jeanine Davis, Margaret Bloomquist and Richard Boylan, North Carolina State University, experts on organic production systems
  • Thomas Björkman, Cornell University. Vegetable physiologist
  • Bryan Brown, NYS IPM. Weed management specialist and expert on organic weed management
  • Jill Eccleston, Cornell University, Integrated control of emerging insect pests

Topics

  • Organic nutrition for a nitrogen-hungry crop
  • Weed management in high fertility and short season
  • Insect management amid many hungry pests
  • Varieties suitable for organic production in the East
  • The market for organic broccoli

Join the webinar by clicking this link: https://cornell.zoom.us/j/855304241 on a computer, tablet or smartphone. To test your Zoom connection in advance, please visit https://zoom.us/test. It may take a minute or so to install the small software.
To get the audio only on a telephone, call +1 646 876 9923 and enter meeting id 855304241

Sponsored by the Eastern Broccoli Project (a multi-institutional project funded by USDA National Institute of Food and Agriculture, Specialty Crop Research Initiative).

Alternaria strikes in 2018, overwhelms Quadris

Alternaria was widespread in the East this year. Unrelenting rain after mid-August created conditions in the Northeast that were conducive to this normally secondary disease. More important, the strain going around was not controlled by the most commonly used fungicide.

Alternaria lesions on head are deep. Even one renders the head unmarketable.

 

Christy Hoepting conducted a fungicide trial to test both our current fungicide program and new materials. Azoxystrobin (Quadris) is widely used, and a 2014 survey in New York showed no resistance. (Cornell pathologists Meg McGrath and Chris Smart are checking for known and novel resistance in 2018 isolates.)

This year, Tim Coolong reported in August that a Quadris-resistant strain was showing up in Georgia. Christy’s trial showed Quadris failing to control in New York. The good news is that the Alternaria was susceptible to fluxapyroxad and pyraclostrobin, the active ingredients in Priaxor. Priaxor is already labeled for use in New York, except Long Island.

The hot and humid weather with heavy rainfall from remnants of hurricanes during August was the perfect storm for Alternaria leaf spot (ALS) to rage out of control in brassica crops across Western New York in 2018. Cornell Vegetable Program fresh market specialists received several complaints about a disease that caused unsightly lesions on both leaves and marketable portions of brassica plants. When ALS attacks the head of broccoli or cauliflower, it renders them unmarketable. Hoepting visited with a grower who was planning to cut broccoli production by one-third, because he had just lost over 85% of his most-recent 5-acre planting to ALS head rot, a loss of $7,500. She immediately set up an ad hoc small-plot replicated trial on his farm in hopes of finding a fungicide that could control this devastating disease.

By the time the broccoli was ready to harvest, differences among treatments in side-by-side plots were striking. In the untreated check, 98% of the heads were unmarketable due to severe ALS, while the best fungicide in the trial, Merivon (fluxapyroxad and pyraclostrobin) had only 5% unmarketable heads.  The fungicides that the grower had been using, Bravo and Quadris (azoxystrobin), resulted in 98% and 49% unmarketable heads, respectively. Commercially available fungicides Switch, Quadris Top and Endura had significantly lower unmarketable heads than Quadris with only 10 to 33%.

Priaxor can be applied at most 2 times sequentially and 3 times total. The only targeted fungicide that can be used with it in a program is Switch (cyprodinil and fludioxonil) because its active ingredients are in different chemical groups (FRAC groups 9 and 12) from those of Priaxor (7 and 11).

If the grower were to adopt a 4-week fungicide program with top-performing fungicides, he could expect to get at least 75% marketable heads. Compared to his Bravo/Quadris program, which only yielded 1470 pounds and net $1,323 per acre, the new program could increase both yield and net profit 5-fold by 5881 pounds and $5,562 per acre, despite a 5-fold increase in cost of fungicides from $44 to $223 per acre. After viewing the fungicide trial on his farm, the grower immediately adjusted his fungicide program to include the most effective fungicides in all of his remaining brassica plantings. He is planning to resume full broccoli production next year with the new fungicide program, which has potential to increase profit by $166,860 in his 30 acres of broccoli. Trial results will be shared with CVP growers over the winter, so all conventional growers can benefit from improved ALS control in their brassicas.

Alternaria leaf lesions with other diseases three weeks after one heavy rainfall event and regular showers afterwards

 

The Alternaria pattern can give false hope. There are lesions on older leaf, then clean younger leaves that grew after the big rain. However, the infection also affects the head.

For a 2014 survey showing all 47 isolates being susceptible to Quadris, see Kreis, Dillard and Smart. Plant Disease. http://dx.doi.org/10.1094/PDIS-03-16-0414-RE

 

Note added January 11: Today at the Southeast Vegetable Conference, Dr. Bhabesh Dutta of the University of Georgia at Tifton showed that the pathogen present in Georgia this year is a different (new) species of fungus that it is not controlled by azoxystrobin. Pathologists around the East are testing isolates from their regions to determine whether this species is the one that cause unusually high losses in the region.

This result is useful in that Dr. Dutta has already identified a fungicide program that should be effective in 2019. If the other azoxystrobin-resistant isolates turn out to be the new species, it mean that there has not been a change in the usual Alternaria.

Seepage irrigation

One fascinating thing about visiting Southwest Florida farms is seeing their distinctive seepage irrigation system. I had heard it described, but I didn’t really get it until I saw it in action.

Unique soils in Florida have allowed growers there to develop a an effective irrigation system that differs in many respects from what I have seen anywhere else. Sandy soils overlay a hardpan just below the maximum rooting zone. That situation allows lateral seepage of irrigation water over considerable distances with hardly any slope.

Main irrigation canals move water from water reserves in the abundant swampland to the fields. To irrigate a field, irrigation ditches are filled from those canals, then emptied when irrigation is done.

 

Irrigation water seeps sideways into the soil from the ditch. It reaches far enough that there are 12 beds between ditches. The water level is maintained precisely so that soil under the roots is wetted, but the roots are not drowned.

 

One of the significant advantages of this system is less disease. Because all the water stays underground,  it is rarer for the foliage to be wet and the humidity, while naturally high, is lower. Thus the conditions for fungal spores to germinate and for hyphae to grow are considerably less common.

A couple other unique features  make the system work. First, the land is very flat. Whole fields can be irrigated where the underground water table is maintained at an exact distance below the soil surface on the bed tops. In addition, field are interspersed with vast swamplands that serve as storage for irrigation water. Irrigation water can not only be drawn from these reservoirs, but it is also returned to them at the end of an irrigation cycle.