Australian soybeans come of age
GroundCover™ Issue: 113 | Author: Bob Freebairn, agricultural consultant, Coonabarabran, NSW
- The GRDC-funded Australian Soybean Breeding Program has developed varieties with yield improvements of 20 to 25 per cent
- Gains have been made in grain quality enabling access to higher-value markets
- Gains have also been made in variety resistance to disease
Soybean grain yield gains of 20 to 25 per cent, improved grain quality and marketability, and advances in disease resistance are some of the measurable outcomes from the GRDC-funded Australian Soybean Breeding Program.
While recent releases have seen significant varietal improvement, new lines in the pipeline suggest that even more improvements are on the way.
The largest soybean production area is the New South Wales north coast. Other important regions include inland northern NSW, the southern Queensland coast, the Riverina, and the north-west of Western Australia and Northern Territory. With a wide latitude range (12° to 36º south) and different daylight-length and district differences in temperatures, disease and environments, developing Australian varieties has been a sizeable challenge.
Most overseas soybean-growing regions are different to Australia, so rarely are these varieties suited to Australia. However, valuable traits from many sources are being incorporated into Australian varieties.
Two new varieties, Richmond and Hayman, typify the gains being made in plant breeding combined with regional assessment and selection.
These releases represent yield gains of about 20 per cent more than the first generation of higher-quality clear-hilum varieties with large seed that were released a decade ago, and about 10 per cent higher than the once predominant dark-seeded types.
High-quality clear-hilum varieties with appropriate protein level and seed size opened the Australian soybean industry to many higher-value human consumption markets compared with the dark-seeded types used principally for crushing (meal and oil).
Hayman sets a new benchmark for high yield, high quality and improved disease resistance for many areas. In some areas it is also the best variety for silage and hay – an important soybean role in many mixed grain and livestock farms.
Hayman is most suited for grain in areas such as the Darling Downs and Lockyer Valley, northwards to the Burnett and Mackay regions of Queensland, and for the NSW north coast in the latest planting window (from the end of January to early February). At the early or mid-season planting windows it has too much biomass for a grain crop, but this is ideal where the objective is hay or silage production.
Hayman has improved protein content and quality, including clear hilum and large seed size. It also possesses the 11sA4 protein null (like Bunya) that is valued by tofu processors for its gelling qualities.
Hayman is suitable for hay and silage production in the NSW north coast and Northern Tablelands areas because of its slower maturity and longer period of pod filling. This can be especially beneficial where delays due to wet weather are common.
Richmond is also a high-yielding release with a high-quality clear hilum that suits the early to mid-season planting window in northern NSW and southern Queensland. It is a compact plant with minimal lodging, and has clean leaf drop and even ripening.
It is resistant to powdery mildew, tolerates manganese toxicity, which is common in coastal soils, and has the highest weathering tolerance of all clear hilum varieties.
Australian soybean areas are different to other soybean-growing regions such as in the US. Desirable traits for Australian growing conditions, such as disease resistance, high quality and agronomic aspects, are not readily available in overseas varieties.
For example, no other major world soybean area other than east-coast Australia faces wet, humid harvests, so searching for improved germplasm has been difficult. Screening at Grafton, NSW, has identified material with better weather tolerance and this characteristic has been incorporated into clear hilum lines.
As the soybean planting window is so wide in areas such as the north coast (sowing times vary from mid-November to early February), varieties with different daylight-length sensitivity and different maturities are required. Using local selection nodes, it has been possible to identify lines developed by Dr Andrew James that fulfil these roles for each region.
As there has been no need for attributes such as Roundup Ready® and Bacillus thuringiensis (Bt) pest resistance, the Australian soybean program has not adopted GM. A non-GM Australian soybean industry is also a bonus for many export markets.
As has occurred in other crops, non-GM tolerance to the Group B herbicide sulfonylurea has been successfully incorporated into soybean germplasm by Dr James.
New South Wales Department of Primary Industries (DPI) research agronomist Dr Natalie Moore says that depending on the region, several important diseases affect soybeans and are addressed by the Australian Soybean Breeding Program.
Phytophthora root rot is a threat in irrigated systems, especially in southern NSW and northern Victoria. While there are many strains, good resistance to the strains known to be important has been incorporated into the latest varieties.
Bacterial pustule and blight-susceptible lines are screened for and susceptible lines are deleted. Material is also screened for good resistance to downy mildew. Powdery mildew resistance is important for areas such as the Liverpool Plains.
Dr Moore is excited by the discovery of resistance to soybean leaf rust, which is rapidly being incorporated into the next generation of varieties.
At least 32 lines of soybean leaf-rust resistance have been identified in a screening nursery at the NSW Department of Primary Industries in Grafton and have been incorporated into the breeding program as a high priority.
Part of the GRDC-supported Northern Pulse Agronomy Initiative research project is to better understand the role of soybeans in fixing soil nitrogen (Nikki Seymour from the Queensland Department of Agriculture, Fisheries and Forestry leads this part of the research) and soil nitrogen build-up for rotational crops following soybeans. Agronomic practices such as sowing time, variety and various management aspects are also being assessed.
A broad understanding that soybeans can leave the soil richer by about 40 kilograms per hectare of nitrogen per tonne of yield means good crops can provide hundreds of dollars a hectare of extra value for subsequent rotation crops.
Other aspects of the Northern Pulse Agronomy Initiative include variety-specific agronomy packages for the various soybean-growing areas. Sowing rates, plant population, optimum sowing time for specific varieties, choice of variety for different rotations (for example, early-sown quick-finishing ones for rotations where another crop is planned as soon as soybean is harvested) and weed and pest control strategies are part of the investigation, specific to individual newly released varieties.
More information:Dr Natalie Moore,
02 6640 1637,
GRDC Project Code CSP 00157, DAN00171
Region North, South, West