Variety selection tool for winter wheat

1. Variety filters

Filters are a simple way to exclude varieties from an analysis. They allow you to specify market requirements, account for key diseases and reflect preferred agronomic features. Only varieties that meet your needs show in the scatter plot chart (bottom right).

Use the drop-down menus to select end-use (e.g. UKFM groups), other market options (suitability for export and distilling), ripening days, latest safe sowing date and resistance to orange wheat blossom midge (OWBM).

Use the green slide selectors (or number boxes) to define preferred ranges for disease resistance, lodging (+ or – PGR), sprouting and grain quality (Hagberg Falling Number – HFN, specific weight and protein). Note: For many fields, it is possible to select values to one decimal place. Often rounded up/down to the nearest whole number in the RL publication (e.g. most disease ratings), the tool provides greater selection power. Note: take care to not exclude unintended data (e.g. to show varieties with a published resistance rating of 7, select a range of 6.5–7.4).

Finally, use Filter panel (2) to interrogate Grain Quality (Protein %, Hagberg Falling Number and Specific Weight) and supplementary yield data: sowing date (early drilled, before 25 September or late drilled, after 1 November), rotational position (second and more) and soil type (light or heavy).

Select ‘Clear all filters’ to reset all values to the RL default values (i.e. as published in the main RL with no varieties excluded).

2. What is agronomic merit?

Disease resistance and good agronomics are considered more crucial than yield by many farmers and agronomists. Agronomic merit is a non-yield based metric that aims to capture the genetic potential for resistance to disease and lodging, to help farmers and agronomists with variety selection. The RL includes resistance ratings for key diseases and lodging. However, the relative importance of these factors will depend on your particular situation. Agronomic merit takes account of a variety’s resistance to six key diseases and lodging as well as their relative importance and is displayed on the X-axis of the chart. The table below provides an example of an agronomic merit calculation.

*RL resistance ratings use a simple scale: from 1 (least resistant) to 9 (most resistant). **Ratings and weightings shown for illustrative purposes. Importance: Very high = 10, high = 7, medium = 4 and low = 1.

By default, the importance of each of the diseases is set up in the tool depending on the regional yield data selected (UK, East, North or West). However, you can determine how agronomic merit is calculated by placing greater importance on things that really matter on your farm. You can do so by clicking the relevant button for each factor. In addition, to view a particular RL resistance rating on the X-axis instead of Agronomic merit, click on the corresponding RL rating button. This sets the weighting for the selected resistance rating to 1 and the others to 0.

3. Disease importance

4. Regions used for calculation of regional yields.

5. Alternative views

The coloured dots can also show a range of alternative views. For example, scope of recommendation (East, West and North) or end-use groups  – use the ‘Distinguish by varieties’ drop-down box.

Yellow and brown rust ratings

The RL 2021/22 featured major changes to the disease-rating-calculation approach for winter wheat yellow and brown rust.

Miscellaneous

Average LSD (5%) values for Yield are overlaid on top of the graphs, the LSDs for other variety characteristics are shown in the first column of the table on the second page, provided no varieties have been filtered out.

Tool updates