Where Carrots Come From
As a someone who did not grow up in a farming family, the past twenty years have been a constant learning about the intricacies and complexities of our global food system. My understanding of food has evolved from “Food comes from the grocery store” to “Food comes from [insert choice of complex explanations here]”. At this point I feel I am starting to know things pretty well – but more often than I would like to admit I am introduced to a new aspect of our food system that expands my understanding of agriculture and how it affects our everyday lives. My latest experience, if you haven’t guessed already, involved carrots.
My carrot revelations came courtesy of Dr. Phil Simon, USDA professor at the University of Wisconsin; Micaela Colley, Program Director at Organic Seed Alliance; and a group of graduate students, post-docs and plant breeders gathered together in Southern California in early March to immerse themselves in the world of carrots.
A World of Carrots
This world of carrots was located at the USDA Desert Research and Extension Centre in Holtville, California, just 15 km north of the Mexican border, where Dr. Simon was overseeing more than 2000 trial plots of carrots as part of the USDA ARS carrot breeding program – a program that started with his predecessor Clint Peterson, along with University of California Extension Specialist Vince Rubatzky, in 1969 and which Dr. Simon took over in 1986 and has been coordinating annually since. These trial plots were a combination of varieties in the USDA germplasm collection (about 750); crosses Dr. Simon made as part of this breeding program; varieties submitted by other breeders; and a selection of market-available cultivars. These plots of carrots represent a good portion of the genetic material available for plant breeders across the World and many carrot breeders from US and international seed and breeding companies were on hand to check out these carrots to see what might make a good addition to their own breeding programs.
I was lucky enough to join this group thanks to Micaela Colley from Organic Seed Alliance (OSA), who I have worked with over the past several years through my role as Seed Security Program Director at FarmFolk CityFolk in British Columbia. While BC seed growers often look to OSA for resources and guidance, we also have a specific interest in carrot seed here in BC. The BC climate is ideal for carrot seed production and since 2013 we have been working on a project exploring carrot seed production in isolation cages due to the prevalence of Queen Anne’s lace in BC – a common weed which freely cross-pollinates with domesticated carrots, rendering their seed unmarketable.
Overcoming the Two-Year Carrot Lifecycle
Carrots are a biennial crop, meaning it takes two growing seasons to set seed. The first season the carrot itself is grown and in the second season it sets seed. In between growing the roots and setting seed, carrots must undergo a vernalization period (exposure to cold temperature for a certain amount of time) to induce flowering and seed set. In Northern coastal climates this can happen in the ground, but vernalization can also be achieved by harvesting the roots and putting them into cold storage.
The Southern California location at the USDA Desert Research Centre offers perfect winter growing conditions for carrots. Carrots can be planted here in October for harvest and evaluation in March. Once the best individuals and plots are selected by Dr. Simon and his team, the carrots go directly into cold storage for vernalization and are shipped up north to be planted for seed production. The seed crop matures in September and can then be shipped back down to California for planting. This allows Dr. Simon to produce seed for this biennial crop in just one growing season and cuts the breeding time for a new biennial carrot cultivar in half.
When doing an evaluation on 2000 plots of carrots you need a pretty good system, and Dr. Simon seems to have things well worked out – he has a great team of graduate students, post-docs and staff to help – most of whom are also working on their own carrot projects under his guidance.
The process starts with a list – a very big list of all the varieties and their locations in the two fields that were allocated to these trials. This list has all the plot numbers; the names of the variety sowed in each plot, and additional details about each variety such as which carrots were the parents that were cross pollinated to produce a certain variety. There were very few fancy variety names in this list as they were mostly still named by numbers at this point.
The next step (we may be skipping a few steps here, but I need to consider my word count) is loosening the soil around the growing carrots so they can be easily pulled and laid on the soil for a visual inspection. One of the research center’s field crew comes by with the tractor and a soil loosening implement and “frees” all the carrots in a selected row. Then the team gets to work – pulling the carrots and laying them across the bed for a visual inspection. Different plots were assessed for different traits and carrots which meet the criteria that Dr. Simon or one of the team is looking for get packaged, labeled, and boxed for the next part of the process – a closer inspection and a tasting.
One of the highlights for me of assessing field trials during this visit was working with Dr. John Navazio of Johnny’s Selected Seeds (and formerly with OSA) who had two rows of his own breeding materials in the field. I have known John for about 15 years as he has been been a regular visitor to BC to lead workshops and field days over the years. Much of my own training in seed production and plant breeding comes from John so it was great to spend some time in the field with him looking at his breeding materials. That said, I might have offended him at one point when he asked our opinion on one of the plots and I responded: “It looks like crap!” After a good chuckle I had to remind him of one of the best lessons he taught me in selection: You may not always know what you like, but you almost always know what you don’t like. Of course, I may have slightly tempered my opinions on other varieties after that plot…
Among the graduate students Dr. Simon had on his team, many of them had projects which included assessing certain beds of carrots for specific traits. One project in particular was that of PhD candidate Charlene Grahn, whose research focus was on carrot top height – a trait that could determine a carrot variety’s ability to outcompete weeds. There were two interesting aspects to this research. The first was one of the methods Charlene used to assess canopy cover in a carrot plot: an app called Canopeo, a camera-based measurement tool that helps measure canopy cover in a crop. Charlene would take a photo above each plot and then use the app to determine the percentage of canopy cover for each variety. The second interesting part of this research was that Charlene was doing it in both organic and non-organic carrots. Canopy cover can be an effective trait for weed suppression in organic crops.
The canopy cover was part of a bigger organic research project called Carrot Improvement for Organic Agriculture:
The Carrot Improvement for Organic Agriculture (CIOA) project is a breeding effort to address the critical needs of organic carrot farmers by developing orange and novel colored carrots with improved nematode and disease resistance, improved weed competitiveness, and improved nutritional value and flavor. The project is also comparing the relative performance of varieties in organic versus conventional farming systems through replicated trials in four states and exploring the response of various genotypes to soil microbial environments.
In many ways it was the organic component of the trials that enticed me to join this group in Southern California, but I also knew the overall trials would be valuable in better understanding carrots and their breeding. It was just a coincidence the research was taking place in a warm climate during the last dregs of a Pacific Canadian winter.
Closer Inspection and Tasting
After the team had done a first selection of carrots in the field the next step was a closer look at many of the varieties on a table in a shadier spot than the field – and a tasting as well. This was where it was quite impressive to see Dr. Simon at work, going through each of the varieties carefully, yet quickly, to select individuals for further breeding. In some varieties only one individual was selected for further breeding while other varieties were eliminated completely – not having achieved the desired outcome from the cross pollination from which they came.
Tasting was an important part of each assessment and generally including aspects of flavour, sweetness, and texture. Small tastes of each variety was key to not letting one’s pallet get overburdened – not a skill I have. Often, after tasting five to six carrots they all start tasting the same to me; so key for me was spacing out tastings to give my palate time to rest, though I did get a little better at tastings over time!
Engaging the Team
While Dr. Simon was focused on assessing each variety carefully, he also did a great job involving the rest of the team in the process – listening attentively to others’ input and often actively asking others in the group which individuals they liked in a certain variety. I remember a group of us all looking at a purple carrot which Dr. Simon was selecting for a yellow core. He asked each of us individually to pick which ones we liked and these were then selected as a group for further breeding. I kind of felt I may have contributed a little to the future of purple carrots in that moment! Here’s hoping it was a beneficial contribution.
This sort of inclusion and engagement from Dr. Simon made my time down there particularly valuable. I was lucky enough to have several moments of one-on-one conversation with Dr. Simon and multiple times he would come find me to follow up on a conversation we had had previously and to show me some examples in the field to demonstrate a point from a previous discussion.
Off to the Cooler for Vernalization
Once all the breeding materials were selected they were immediately put into coolers to start the vernalization process. They were then put into a refrigerated truck and shipped north for seed production. Most of the carrots were sent to Wisconsin while many made their way back to Washington State where the Organic Seed Alliance would oversee their next stages of development in organic systems. It was tempting to obtain some roots to bring back to BC for seed production, but I didn’t have the time or energy to do the paperwork required to bring the roots across the border. So I will just keep in touch with OSA to keep up to date on progress with those varieties.
This experience working with Dr. Simon and his team in Southern California was extremely valuable in understanding carrots from both a breeding and seed production perspective. This immersion in carrots, and in working closely with so many people doing research with carrots, will certainly help improve my carrot seed production skills and help me better assess carrots in our own carrot variety trials back in BC. I can’t wait to visit these plots again in early 2020 on my next working holiday!