Author: Brian

Without bumble bees, a flowering plant that can self-pollinate lost substantial genetic variation within only nine generations, an experimental study found.

A group of “selfing” monkeyflower plants lost 13% to 24% of their genetic variation compared to another group that were propagated by bumble bees. This loss could rob the plants of their ability to adapt to environmental challenges, according to the study published in the journal Evolution. With bee populations on the decline in nature, the findings point to serious issues for wild plants and crops that rely on these pollinators.

“We found that in a very short amount of time, there were major consequences on the genomes of the plants when they had to adopt selfing,” said Jeremiah Busch, a Washington State University evolutionary biologist and lead author on the study.

Pollinators like bees are important to biodiversity in their own right, Busch added, but the study indicates that their decline will also have potentially devastating impacts on plants, and quickly.

“If pollinators are lost, it’s not just going to be a problem for the pollinators: plant populations will lose genetic variation in tens of generations — not thousands, but tens,” said Busch.

While scientists have known that adopting self-pollination can endanger a plant species’ long-term survival, they did not know exactly how that worked genetically or how quickly.

Busch’s colleagues set up a controlled greenhouse experiment using yellow monkeyflower plants, a common wildflower found in the Western U.S., in which a group of plants were isolated from their bumble bee pollinators. At first the non-bee plants produced few seeds, then they produced a lot as they adapted to self-pollinate. The flowers changed as well with their male and female reproductive parts, the tops of their stamens and pistils, moving closer together to allow for the easier transfer of pollen.

While the selfing plants continued to reproduce, they lost genetic variation compared to a control group that were visited by bumble bees.

Adaptation is key to explaining these surprising declines, Busch said. In selfing populations, a favored genotype will spread if it has an advantage, but so do all other mutations it carries, simply because they are lucky enough to reside in that plant’s genome. This phenomenon of “genetic hitch-hiking” is much less pronounced when bees visit plants because offspring are a mix of their parents’ genetic variability.

“Strong inbreeding fundamentally altered the consequences of adaptation,” he said.

Future research should follow plants over a longer period of time to see if and when the loss of genetic variation leads to population collapse, said Busch.

“A really important next step is to see how fast highly inbred groups will have their viability decline over time – to know how quickly those populations will go extinct,” he said. “We need to really understand what the consequences are from pollinator loss. It will matter for wild populations of plants and crops. A lot of crops depend on bees.”

This work was supported by the National Science Foundation as well as a WSU sabbatical to Busch that allowed him to work with co-authors John Kelly and Sharif Tusuubira at University of Kansas as well as Sarah Bodbyl-Roels from the Colorado School of Mines.

USDA Farm Service Agency has launched the Food Safety Certification for Specialty Crops (FSCSC) Program, a new cost share program that provides financial assistance for specialty crop operations that incur eligible on-farm food safety program expenses related to obtaining or renewing a food safety certification in calendar years i2022 or 2023. To receive the financial assistance, the following eligibility requirements (among others) are required: have obtained or renewed a 2022 food safety certification that was issued between June 21, 2022, and December 31, 2022; have paid eligible expenses; be a specialty crop operation; and meet the definition of a small business or very small business; and be located in the 50 United States or U.S. territories.

Costs covered by the program include:

• Developing a food safety plan for first-time food safety certification
• Maintaining or updating an existing food safety plan
• Food safety certification (audit) costs
• Microbiological testing for water, soil/amendments, and products
• Food safety training
• Certification upload fees

Learn More: FSC Specialty Crops


Todd Mattos, Program Manager
Northwest Territory
USDA AMS SCP SCI Division
410 North Kings Road, Ste. 118
Nampa, Idaho
Cell:  (208) 650-0256
Office (208) 467-6187
Email: todd.mattos@usda.gov

Research looks at ways to increase adoption of public food forests in communities

Public food forests exist on publicly owned or stewarded land. They are designed to be open to local residents to participate in their implementation and development. The July 22^nd, 2022 Sustainable, Secure Food Blog looks at recent research into some obstacles small cities and towns have in developing more public food forests.

According to blogger Sarah Coffey, public food forests can vary in their design. An ideal design would use the vertical space of the forest well. Low shrubs with tall trees. Ground cover could be replaced with herbs.

Each species plays a different role in this type of agroecosystem. These multiple storied polycultures (i.e., growing multiple crops at once in the same space) can optimize yields in a sustainable and regenerative way.

To learn about these perspectives, Coffey and her colleagues surveyed mayors of towns in Virginia, USA, with less than 25,000 residents.

Only 20% of towns that included food production systems in their plans included food-bearing trees and shrubs. (Most included vegetable gardens and annual crops). And the majority (80%) didn’t include municipal ordinances for implementing food forests. A plan like this would include where, what, and when to plant.

The study found the mayors’ greatest perceived concern was how they would be maintained in the long-term. This included aesthetic and safety issues associated with downed fruits and obstructing visibility in rights-of-way. A lack of physical space and competing within these spaces with other, more profitable uses, were other barriers.

The research team has several suggestions to increase adoption of public food forests, including:

• Developing municipal ordinances that protect food forests from competing uses.
• Partnering with non-governmental organizations, land trusts, schools, or places of worship to address long-term maintenance concerns.
• Emphasizing the benefits that are aligned with those of traditionally valued green space.

“Our findings suggest that stressing these aspects of a food forest rather than just food production and ecological benefits could increase acceptance by elected officials or city/town staffers,” says Coffey.

To read the entire blog, visit: https://sustainable-secure-food-blog.com/2022/07/22/what-are-public-food-forests/

Photo: Public food forests can provide several “services” to the community, in addition to providing food. These berry bushes, for example, have roots that help absorb water from heavy rains, reducing stormwater loads. They provide food to pollinators, improving biodiversity. Credit: Morguefile.

For high-resolution photos please contact Caitlin Heitman, cheitman@sciencesocieties.org.

Washington State University will be hosting an insect and weed control field tour on July 20^th from 2-4 pm.
 
Join them at the WSU Commercial Vegetable Farm in Pasco to view experiments funded by the CBORC and Washington State Commission on Pesticide Registration focused on pre-emergent herbicides and various treatments for control of seedcorn maggot. The plot tour will be begin at 2 pm and conclude at 4 pm. Research results will be discussed and attendees will be able to view the results first hand. This is not their standard onion field day focused on cultivar evaluations. That field day will be held August 25^th near Quincy.
 
Location: Washington State University Commercial Vegetable Research Farm, Pasco, WA. Plots are near the intersection of A Street and Heritage Blvd. Approach from that intersection, proceed south through the open gate onto the gravel road. Follow the road to the south and west and the small (10 acre) circles will be directly on your right (West) about ½ mile down the gravel road. The onion plots are on the South side of the Western most pivot.


Tim Waters, Ph. D.
Professor/Regional Vegetable Specialist/Franklin County Director
Washington State University Extension Franklin and Benton County
Agriculture and Natural Resources Unit, CAHNRS
Mobile: (509) 545-3511
Email: twaters@wsu.edu

Carrie H. Wohleb, Ph.D.
Associate Professor / Potato, Vegetable & Seed Crops Specialist
WSU Extension – Grant County – Columbia Basin
Agriculture & Natural Resources Program Unit, CAHNRS
Washington State University
Mobile: 509-707-3510
Email: cwohleb@wsu.edu

Teleos Ag Solutions will be hosting two fumigation stewardship training events in August.

The first will be in Moses Lake on August 2 at the Big Bend Community College.  The second will be in Kennewick on August 3 at the 3 Rivers Convention Center.

There will also be an online option for those who can’t attend in person.

Click HERE for more information, including the agenda with start times and speaker information.

A light breakfast, raffle items, and a buffet lunch will be provided.

Please RSVP by July 30, 2022 to rmatson@teleosagsolutions.com.

Certis Biologicals has launched MeloCon LC, a water-dispersible concentrate containing spores from a naturally occurring soil fungus which controls a variety of harmful nematodes at every lifecycle stage.

The improved liquid concentrate formulation of MeloCon LC provides greater convenience in storage, handling and tank-mixing and allows for application flexibility when fumigant and conventional chemistries cannot be applied, according to Certis.

MeloCon LC is labeled for use in all states except California, with registration pending.

Visit www.certisbio.com.

By Christopher G. Galbraith and Sushila Chaudhari, Michigan State University

Carrot growers have faced their share of weed control challenges in recent years. Growing resistance to herbicides from important modes of action, such as the photosystem II inhibitors (Group 5), has led to reduced efficacy and an increasing number of escaped weeds. These escapes threaten yield potential in future seasons if allowed to reach reproductive maturity and disperse seed, increasing not only weed pressure but also prevalence of resistance genes in the population.

When early-season control fails, new practices are required to handle these larger weeds that are no longer susceptible to herbicide application. The standard strategy in west Michigan and other regions is to hire teams of hand labor to manually remove weeds before they are able to set seed, a practice which poses a major financial burden to growers. As the need for better late-season control continues to rise, growers are looking for new tools and technologies that will help them take action.

Herbicide Programs for Early-Season Control

Beginning the season with strong control through selection of effective herbicides and practices is essential for optimizing yield in slow-emerging crops like carrot. Surface cultivation, flame-weeding or application of a burndown herbicide can be used to clear existing weeds prior to crop emergence. Numerous cultivation implements can be used for between/in-row weeding throughout the season.

Preemergence chemical options include linuron (Lorox 50DF), pendimethalin (Prowl H₂O), prometryn (Caparol 4L), S-metolachlor (Dual Magnum) and trifluralin (Treflan 4EC). Linuron and prometryn can also be used postemergence for broadleaf control, along with metribuzin (Tricor 4F). Postemergence options for grasses consist of fluazifop-P (Fusilade DX 2E), sethoxydim (Poast 1.5E) and clethodim (Select Max 0.97E). Herbicide application rates can be found in Fig. 1.

While starting out with effective control is crucial, it is also important to plan for control of escaped weeds later in the season as part of an overall integrated weed management program.

Electrical Weeding: A New Option for Late-Season Weed Control

Electrical weeding is an emerging technology that is sweeping across many agronomic and horticultural crop industries. Commercial equipment is available that terminates weeds through contact with a tractor-mounted, high-voltage electrode which is charged via a power take-off driven generator/transformer system. Upon contact, the current is conducted through the weed as it returns back to its source through the soil and a grounding device. Electrical energy is converted into heat as it moves through the plant, causing systemic tissue death. This novel practice is being leveraged as a form of late-season weed control by Michigan carrot growers to manage escapes, resistance and the weed seed bank.

A summer 2021 research trial at Michigan State University put electrical weeding to the test by evaluating its success within various control programs. Different combinations of early-season Prowl/Lorox applications with variable timing and number of electrical weeder passes performed later in the summer were compared in terms of crop injury and weed control. Yield data and in-season foliar injury ratings were collected to discern the level of inadvertent crop damage. Carrot root subsamples were also taken at harvest to determine both average length and extent of damage to internal tissue from the electric current.  

Results show that two electrical weeder passes applied at the same time is optimal in terms of balancing control and operating costs. No evidence was found to indicate that any of the electrical weeding treatments cause damage to the crop’s internal root structure. Two electrical weeder passes in succession did show slightly higher foliar injury. However, there was no meaningful difference in carrot yield or length between any of the non-chemical treatments (Fig. 2, Fig. 3) besides slight variation resulting from higher weed pressure found in plots where two passes were applied in succession.

This finding indicates that electrical weeding’s primary benefit may not be so much that it boosts yield in the current season, but that it can reduce pressure in later years by eliminating mature weeds before they set seed. Electrical weeding serves as a form of long-term weed management when employed to clean up fields following early-season control practices, preventing further replenishment of the weed seed bank and escaped weeds from interfering with harvest.

These preliminary results showing electrical weeding’s effects on weed control and crop damage are just the beginning in terms of the potential of this new technology. The current research program at Michigan State is testing the effects of electrical weed control on environmental factors such as weed seed viability and microbial populations inhabiting the root zone. Data from the research is also being used in constructing a profitability analysis between electrical and hand-weeding to determine which is more cost effective. There is also growing interest around the potential of electrical weeding for elimination of bolting carrots in order to prevent harvest of these unmarketable roots. As growers are faced with the dire challenge of controlling resistant weed populations, electrical weeding shows promise as a viable option for improving integrated weed management in modern carrot production.

Authors’ note: Funding for this research was provided by USDA National Institute of Food and Agriculture (NIFA) Hatch Project number MICL102562, MDARD State Specialty Crop Block grants, USDA NCR-SARE Graduate Student Grant and the Michigan Carrot Research Committee.

By Bill Rolling and Phil Simon, USDA-ARS Vegetable Crop Research Unit

USDA researchers are taking a close look at exactly what makes some carrot seeds germinate better than others in an effort to ultimately breed cultivars with improved germination. The work starts with the USDA carrot germplasm collection, which contains seed of more than 1,800 carrot accessions from around the world. This collection is a tremendous resource for carrot cultivar improvement because it contains incredible genetic diversity representing novel traits for improved environmental stress tolerance, pest and disease resistance, and beneficial plant physiology.

In 2016, a USDA project was initiated to identify beneficial traits in the USDA carrot collection and to use “fingerprints” found in the genetic data to efficiently introduce novel traits into production cultivars. The traits studied as part of this project were selected based on a survey of carrot industry stakeholders. Over 80 percent of the respondents of this survey were interested in improved germination. This is an important trait to emphasize because strong germination and stand establishment can reduce weed pressure without additional herbicide application, and consistent stands result in more harvestable roots.

The USDA carrot germplasm collection is a great place to look for novel traits relating to strong germination and stand establishment. With this goal, over 700 accessions from the USDA carrot germplasm collection were grown in Hancock, Wisconsin, to determine if there is variation for germination and to provide initial observations of accessions that are strong or weak germinators.

Search for Strong Germinators

Preliminary results from that previous project led to the current study titled “Screening Diverse Carrot Germplasm for Improved Germination and Seed Characteristics” funded by USDA-NIFA (#2020-10758). There are two major parts of this project: (1) identify accessions from the USDA carrot collection that germinate exceptionally and can be used to improve germination in cultivars; and (2) test if seeds’ traits such as size, shape or weight can be used to identify higher quality seeds with higher germination.

A total of 225 carrot accessions from the USDA collection are included in the study to identify parents to include in breeding programs targeting higher germination. Germination is highly complex, affected by genetics, the environment, and interactions between genetics and the environment. For this reason, seeds are being produced in a controlled greenhouse environment with each of the accessions represented by three to six individual plants.

Seeds were harvested in 2021, and a second replication of seeds is being produced in 2022. With this experimental design, the practicality of breeding for this trait can be estimated, while at the same time identifying those accessions that can be sources of improved germination. Once produced, seeds will be tested as to how well the seeds germinate in a controlled environment under optimal conditions, as well as challenging conditions including cool and overly warm temperatures.

Role of Seed Characteristics

Ten inbred varieties from the USDA carrot breeding program were used in experiments to estimate the relationship between seed characteristics and stand establishment. The seeds of these inbreds were quality “graded” by passing seeds through soil sieves to separate larger seeds and smaller seeds, followed by weighing the seeds. Seeds were considered high quality when they were larger and heavier and low quality when smaller. The germination and stand establishment of quality-graded seeds are being compared to a random sample of seed when grown in Hancock, Wisconsin, and El Centro, California.

Germination and carrot canopy height measurements were taken throughout the 2021 season at Hancock, Wisconsin. There, the high quality and low quality seeds germinated similarly. This matched results from a controlled environment germination experiment where quality-graded seeds had similar viability, though the lower quality/smaller seeds did germinate at a slightly lower percentage. Despite similar germination, this single year of results indicated that the high quality seeds were producing larger seedlings that were developing more quickly over the first six weeks of the growing season.

In El Centro, California, measurements were taken at the end of the growing season, with the number of harvestable roots acting as a proxy for stand establishment. Here, the high quality grade out-produced the low quality grade, and a significantly larger number of harvestable roots were produced.

This research will continue throughout 2022-23 to replicate the experiments completed in 2021. We look forward to sharing the final results of this project in 2023.

Experimental carrot hybrids with potential nematode resistance attracted the attention of researchers at the annual USDA carrot hybrid trial.

The trial featured 70 cut-and-peel types, 90 cello types and 90 novel types of different sizes, shapes and colors. Entries included commercially available carrot varieties and hybrids from seed companies as well as experimental varieties and hybrids from seed companies and public institutions such as USDA-ARS.

The trial gives carrot producers and breeders a chance to see how hybrids and varieties perform under the same growing conditions and is meant to identify carrot breeding material and eventual new varieties with improved production, quality, and disease resistance qualities.

Of note in this year’s trial was the number of cello experimental hybrids from the USDA-ARS program that have parents with nematode resistance. Tom Horejsi with the USDA-ARS in Madison, Wisconsin, who helps set up the trial, pointed out that these hybrids could provide growers with options to produce carrots in soils with nematode infestations.

The trial was planted at the University of California Desert Research and Extension Center in El Centro, California, in late October 2021 and harvested in early March. Due to COVID restrictions, the harvest and evaluation of the trial was not open to the public and trial scores will not be posted. However, a limited number of judges did evaluate the trial for traits such as uniformity, shape, color, size and percentage of marketable roots from each entry.

Photos of entries in this year’s trial can be viewed online at www.vcru.wisc.edu/carrottrial. The website also includes trial results going back to 1998. This trial has been ongoing since the late 1960s.