Choosing New Wheat Varieties
By John Fowler, District Agronomist with NSW DPI at Deniliquin (November 2011)
Wheat growers are often faced with the task of selecting a new variety. The decision as to which variety to choose can be a little daunting as there are dozens of new varieties to select from. In order to make a wise and informed decision, growers need access to accurate and unbiased information on all varieties available to them. They also need an objective selection process that highlights the better varieties and eliminates those less suited to their needs.
An excellent source of information on most winter crop varieties is the “Winter Crop Variety Sowing Guide” produced annually by NSW Department of Primary Industries. This booklet is available free of charge to all NSW growers, and can be obtained from your District Agronomist or viewed online (at http://www.dpi.nsw.gov.au/agriculture/field/field-crops/winter-cereals/winter-crop-variety-sowing-guide). The Victorian DPI also produces similar information which is available on their web site.
The booklet contains information on well over 100 wheat varieties, and can be used to systematically eliminate most varieties, bringing the selection back to one or two varieties. One approach is to:
- Select the top 10 yielding varieties for your region (NSW is split into the northern and southern silo groups, which are then further divided into east and west);
- If selecting for irrigation, eliminate those with poor lodging resistance;
- Eliminate all varieties not in the desired maturity range;
- Eliminate varieties with lower grain quality attributes (unless they are very high yielding);
- Evaluate the disease resistance of the remaining varieties (decide on which diseases to give priority);
- Incorporate any other specific selection criteria (eg. acid soil tolerance, herbicide tolerance or resistance, sprouting tolerance, etc);
- Make a selection from the 2 or 3 remaining varieties.
An alternative to this paper based selection technique is a simple computer program available on the “CropMate” web site. To access the program, go to http://cropmate.agriculture.nsw.gov.au then enter your location (eg. NSW, Deniliquin), select “Sowing” from the menu on the top line, then select “Variety Chooser”, enter the information in the drop down menus and you will be given a reduced selection of varieties and their relative yield performance. (This site contains a wealth of useful information for croppers, it is well worth visiting.)
Yield Performance The starting point for variety selection is yield performance. The sowing guide has tables summarising the yield performance of early sown varieties (ie. before 15 May) and main season sowing times. These tables compare the performance of varieties over the past decade, to a standard (eg. Janz for main sown trials) in percentage terms. They also indicate how many trials each variety has been in to generate the data (shown in brackets after the relative yield information). Data on varieties that have only been in a few trials (eg. less than 15) is less reliable than data on varieties that have been in many trials. The relative yield of newer varieties tends to decline marginally (usually 1 – 2%) once it has been included in more than 15 trials.
Lodging Resistance When selecting varieties for fully irrigated sites where the yield potential is regularly over 5 – 6 t/ha, then lodging resistance is essential. Data on lodging is contained in the “Varietal characteristics and reaction to disease” table on pages 14 – 16 in the 2011 guide.
Maturity grouping Ensure the variety you select suites your preferred sowing time. Most often, it will be varieties for main sowing times, so quicker maturing lines (eg. Axe) or longer seasoned varieties (eg. Mackellar) are not likely to suite. However, these varieties will have an important role for late (eg. Axe in June) or early (eg. Mackellar in March) sowings.
Grain Quality The maximum grain quality rating for each variety is clearly indicated in the sowing guide. Unfortunately, some high yielding varieties have a grain quality classification below the desirable APH or AH level. The variety Waagan for example has a maximum quality classification of ASW. This means it needs to have other desirable attributes in order to compensate for the potential lower grain price. The maximum grain quality rating will only be achieved under certain growing conditions. Grain size, grain protein, screenings etc are all impacted by crop agronomy and seasonal conditions. It is also worth noting that the grain quality of some varieties will vary depending on where they are grown. For example, the variety Young is rated APW in the north of NSW, but AH in the south.
Disease Resistance There are a number of disease issues to consider when selecting a variety. These include:
– the seriousness of the disease (does it decimate yield or does only have a small impact on yield?);
– the frequency of the disease (is it likely to be present every year?);
– the ready availability of control measures (can I successfully control it with fungicides?);
– the expense of control measures (are the fungicides relatively cheap to use?).
Select varieties that have good levels of resistance to the diseases most impacting your location. Be aware that disease resistance ratings may change from year to year, especially with Stripe Rust, as new strains of the pathogen develop.
Additional Selection Criteria There may be other selection criteria worth considering, such as:
– acid soil tolerance;
– sprouting tolerance;
– herbicide tolerance or resistance.
Some of this information is readily available, and is contained in the tables on pages 14 – 16 of the “Winter Crop Sowing Guide”. The information on tolerance of most varieties to a range of registered herbicides is contained in the “Weed control in winter crops” booklet, published each year by NSW DPI (a free publication, availed through your district agronomist or on the DPI web site).
New Herbicide Resistant Varieties
The release of the new “CL Plus” lines of wheat have given growers an additional herbicide management tool that should be considered. These lines are tolerant of the Group B herbicide imidazolinone (eg. Intervix -R-), which can be useful in the control of difficult weeds, particulary brome grass. Weed populations can develop Group B herbicide resistance relatively quickly, so these products need to be used with due diligence. However, they are a very usefil tool to incorporate in an overall weed control strategy.
Disclaimer: The material presented on these pages is from official and other sources and is considered reliable. It is provided in good faith and every care has been taken to ensure its accuracy. Ian Lea and Staff at Superior Seed Co. do not accept any responsibility for consequences which may arise from acceptance or recommendations made.