Different versions of this article appeared in In Good Tilth, ACRES USA, and Organic Producer
On-Farm Variety Trials – A Valuable Tool for Innovation
By Matthew Dillon
Quality genetics within a cultivar provide a farmer with crops that work well within their production, processing, and marketing systems. The optimal cultivar will help a producer bring in a crop with high resistance to environmental extremes and the stress of pests and pathogens, appropriate maturity to maximize market opportunities, and the nutritional and taste qualities for their costumers. A farmer who sources inappropriate cultivars is more prone towards crop loss, poor market sales, and in the case of organics, could put them at a regulatory risk of losing organic certification. Additionally, in organic production there are fewer “spray on solutions” to problems in the field so quality genetics are all the more important as a risk management tool.
Deciding which cultivars to plant is a complex and personal choice for producers. Influencing factors include past experience, recommendations, photos or descriptions in a seed catalog, evaluation reports from trials, customer demand and leaning over the fence to see what the neighbors are growing. Planting a new crop or selecting a new variety entails a degree of gambling, but the more information a producer has regarding the available cultivars on the market within a crop type, the higher the likelihood that they will minimize the risk inherent in that gamble. On-farm trials are the most direct and intimate way to gain this information as they are tailored toward site-specific challenges, yet many producers avoid conducting trials because of the labor and land commitment, or because they lack the skills to conduct them effectively.
For several years Organic Seed Alliance (OSA) has been in discussions with farmers, educators, seed companies, and researchers to develop a network of on-farm trial information to assist producers in choosing the most appropriate germplasm for their needs. The longterm vision includes an online database that producers or researchers could search for on-farm trial data by region, crop, genetic characteristics and/or varietal name. As a first step in this process Organic Seed Alliance worked with a diverse team of collaborators to develop an “On-Farm Variety Trial Guide” and a series of field days to demonstrate the benefits and methods of trials. The Guide covers benefits of on-farm trials including compliance with the NOP rule, planning and designing a trial, sourcing germplasm, trial methods and management, how to assess data, and templates for recording and managing trial data.
Perhaps you are considering expanding your crops this year; you want to add fresh herbs to sell to local restaurants; the idea of a a rainbow bunch of colored carrots seems like a good eye catcher in your farmers market booth but you are only familiar with classic orange varietals; a couple of acres of dent corn would decrease the feed bill for your layers but your not sure what variety will have the best emergence in your cold spring soils. Or perhaps you just aren't happy with how often you need to weed that acre of carrots, and wonder if you can find a variety with fast growing tops that will out compete the weeds without losing any root quality or yield. Knowing the basics of on-farm trials can make your innovation easier. Here's an overview of what you will find in the Guide.
Basics of On-farm Trials
- Trial Practicality and Objectives: Trials require resources, so don't juggle too many trials in a single season. Determine what you can invest in labor and land. Prioritize crops that are of particular economic importance, crops that you are considering introducing or expanding, or those for which you are having a difficult time sourcing seed. Prioritize your objectives and the traits you will be scoring. Are you looking for new varieties to diversify your fresh market offerings? Is there a need for a variety that meets a certain challenge like frost tolerance? Or is the goal to find good organically available varieties?
- Variety Selection and the Importance of a Standard: Once the objectives are identified then its time to start scouring seed catalogs for varieties that meet your criteria. Look for descriptions of the traits you desire. Always include a familiar, standard variety (one you normally produce) as a benchmark in the trial. This provides a point of reference when evaluating the trial varieties and is useful to check if the current season’s conditions are abnormally affecting the crop. If you experience environmental extremes during the trial, and your standard does poorly along with your trial varieties, then you know that it was probably due to conditions, rather than your trial varieties having poor quality genetics.
- Determine and Plan Your Trial Method: There are times when a producer may only be able to plant test rows to gather varietal information, and this observational snapshot can be helpful. However, randomized replicated blind trials will give you the most scientifically sound – and useful – information. Varieties are assigned number, markers/tags are created with these numbers, and the varieties are planted in multiple blocks in the field. In one block the varieties can be planted in an ordered fashion (1-n) while in all other blocks the order is randomized to avoid field effect (extreme positive or negative conditions). Draw numbered tags out of a hat, then sow and record with a plot map. Replicating and randomizing increases the assurance that the differences observed between the varieties is really due their genetic differences, not the result of field variability.
- Consistent Practices, Inputs and Field Location: If you want to compare the nature of varieties you have to give them the same nurture. From seeding to harvest, treat each variety in your trial equally, with the same inputs, irrigation, potting soil, fertility treatment, etc. If varieties are not treated consistently, then your observations and scoring will be skewed. In order to minimize variability, select a location with relatively uniform conditions, where soil type, irrigation, drainage, sun exposure are as equal as possible throughout the field. Avoid planting trials on the edge of a field as conditions there tend to be highly variable.
- Record Keeping: Keep a good research log. Record varietal names and seed source, planting dates, transplanting dates, maturity, etc. Make sure all trial varieties are identifiable through the season. Planting tags are useful, but always make a map as tags can disappear or be damaged by workers, machinery, or Mother Nature.
- When to Score a Trial: You can score a trial at multiple times in the season depending on your objectives - emergence in seed trays or in the field; juvenile stages of development for harvest reasons or for assessing the varieties ability to compete against weeds; early maturity or ability to hold in the field. For crops that you are familiar with you can usually project the dates you will need to score based upon timing of planting. Keep a good watch so the crop doesn't get ahead of you. There's no benefit in scoring baby leaf salad spinach when it's already bolting.
- Invite an additional set of eyes: It helps to have more than one evaluator when scoring a trial. Consider inviting neighboring farmers, interns, local consumers, chefs, or buyers for a grocer or distribution company to assist you. Integrating this customer feedback loop can really open your eyes, and gives your accounts a sense of personal importance. We've seen farmers make deals right in the middle of an evaluation because of the way a variety leaps out at one of their customers.
- How to Score a Trial: You can use a pad of paper or a spreadsheet to score the trials (evaluation template available with Guide). We suggest using a 1-9 scoring range. Walk the field for a while to get a feel for the differences in the varieties. Begin with one trait, early maturity on tomatoes for example. You may decide to actually count ripe fruit for all the plants in the variety, or it may be obvious enough that you can simply visually assess varieties for their degree of maturity. Stick with the same assessment technique once you begin. Always find your 1s (in this example, least amount of overall maturity in the variety) and your 9s (highest amount of maturity) first. Once you get clear with these extremes you can begin to walk the blocks and record your scores for all varieties. Score all traits. Along with scoring, take the time to write out your observations - information that might not be captured in numbers. Collect all of the evaluators' observations and data and average out the scores.
As you go about making your seed choices this season, consider conducting a trial and familiarizing yourself with this process. The process of challenging and expanding your knowledge base of crop genetics can be enjoyable with the right planning and tools; it shouldn't feel like a trial. Best of luck.
- Assessing Data: The ultimate goal of trialing is to help direct your crop and variety choices. Data should ultimately serve to assist in your decision-making process. Data may be in the form of numerical measurements, qualitative scoring, or observational notes. Each of which offers benefits. A formal, publishable research trial requires at least three replications in order to conduct valid statistics. The Guide includes descriptions of how to statistically analyze a replicated trial. However, observational trials (one replication) or two replications can still offer some useful information. Many growers prefer to record notes or score varieties on a scale, rather than take measurements as it is easier, less time consuming and allows incorporating a range of qualities in one impression. Others are number crunchers and find value in actually measuring traits such as yield to see which variety produced over time. The key is to record your results diligently in order to compare performance from year to year. Often the best and worst will stand out from memory, but some of those in between, might be important to retrial as performance varies from year to year. We suggest at the end of the season to at least record an overall ranking of varieties based on your key criteria, so that you know which ones to put into production, which to trial again, and which to drop out of the system.
The On-Farm Variety Trials Guide is available for free download here.
Matthew Dillon co-founded Organic Seed Alliance in 2003 and currently serves as an advisor. Prior to OSA, Dillon was the Executive Director of Abundant Life Seed Foundation.