Cultivar Development
Overview
Every year, the WWQL Cultivar Development Team gathers samples from the state Variety Testing programs for Oregon, Washington, and North Idaho. For each market class within each state, five locations are selected that fulfill the following:
- An average test weight that would put them into US Grade #2 or better
- An appropriate protein content for their market class
- No apparent Falling Number issue
Each sample will be tested on roughly two dozen parameters and analyzed using Student’s t-score to determine differences from the check variety. What this tells us is how the test average compares to the check average, taking into account the variation of both.
To make it into the annually published Preferred Variety List, there must be three years of data and at least 15 paired observations between the test and check, grown in the same year and same location; this is because fifteen observations is where the t-score tends to stabilize and change very little with more observations. Three years also allows for “smoothing out” of difficult years, as we know some varieties are more tolerant to environmental stress than others.
Some of the benefits of the t-test are that they’re unbiased, objective, and trait-specific with weights consistent with industry needs. We perform this t-test for each individual quality trait; however, not all traits are included in the final t-score calculation and traits are weighted based on importance to industry. The weights were decided on by the PNW Wheat Quality Council ~25 years ago and have been revisited every few years to ensure their relevancy to modern markets. For example, in soft wheat, milling and baking are heavily weighted as those are the primary drivers of the quality standards our wheat is held to.
