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Organic on-farm variety trials

Quality genetics within a cultivar

By Matthew Dillon

Quality genetics within a cultivar provides a farmer with plant materials that work well within their production systems. The optimal cultivar will help a producer bring in a crop with resistance to environmental extremes, pests and pathogens, be attractive and flavorful and mature early to maximize their market. Simply stated, the best inputs will result in the best product output.

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 certification. 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 and customer demand. There is a degree of gambling involved, so the more information a producer has of the available germplasm within a crop type, the smaller the risk. On-farm trials are the most direct and intimate way to gain this information tailored toward site-specific challenges, yet many producers avoid conducting trials because of the labor and land commitment, or lack the skills to conduct them effectively.

For several years the 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 long-term 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 is working with a diverse team of collaborators to develop an On-Farm Variety Trial Guide and host regional educational workshops. OSA was the recent recipient of an USDA-RMA partnership award for the "On-farm Varietal Trials” (OVT) project. The Guide will be available in printed and online versions in June, with field workshops over the course of the summer of 2007 (more information and dates will be available at

The Guide will cover 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. OSA Farmer Outreach Coordinator Micaela Colley and Dr. Jim Myers, professor of plant breeding at Oregon State University (OSU), will be the primary authors of the OVT Guide with assistance from project collaborators at the regional universities (OSU, WSU, University of Idaho, and of Alaska) and certification agencies (Oregon Tilth and WSDA). The Guide will be distributed at farm conferences, via extension, Oregon Tilth, and Organic Seed Alliance.

Organic producers are strong partners on the project, assisting in the creation of the guide and the teaching of the field workshops, as well as conducting field trials to be used in the workshops.

Six partnering producers in the Risk Management Agency Western Region states of Oregon, Washington, Idaho, and Alaska will conduct variety trials that are appropriate to their regions. The first field trials and workshops will occur at the six partnering farms with plans to expand the trials and workshops throughout the northwest and nationally. OSA is in discussion with several funders for this expansion, and to develop the online database linking the data generated from the on-farm trials.

Basics of on-farm trials

While the OVT Guide and workshops will explore many of the benefits, pitfalls, and details of on-farm trialing, there are basic steps that producers can take to begin this process on their own.

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 snapshot can be helpful. However, randomized replicated blind trials will give you the most scientifically sound – and useful – information. Varieties are assigned numbers, 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 to 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 and 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 use scoring baby spinach when it’s already bolting.

How to score a Trial: It helps to have more than one evaluator when scoring a trial. Invite neighboring farmers, interns, chefs or other customers to assist you. You can use a pad of paper or a spreadsheet to score the trials (evaluation available at on the Publications page). 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.

Assessing Data: The ultimate goal of trialing is to help direct your crop and variety choices. Data should serve to assist in your decision-making process. A formal, publishable research trial requires at least three replications in order to conduct valid statistics. The OSA Guide to On-Farm Variety Trials will include 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. 

As you go about making your seed choices this season, consider conducting a trial and familiarizing yourself with this process. It shouldn’t feel like a trial. The process of challenging and expanding your knowledge base of crop genetics can be enjoyable with the right planning and tools.

We hope to see you at one of the On-farm Variety Trial field days in the summer. Best of luck!

Matthew Dillon is the founder and Executive Director of Organic Seed Alliance.

For more information, contact the Organic Seed Alliance,, (360) 385-7192.

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