Wheat breeding for the north - the impact of new technologies and breeding targets
Author: Haydn Kuchel, Meiqin Lu, Tom Kapcejeves, Kerrie Gleeson, Steve Jefferies - Australian Grain Technologies | Date: 25 Feb 2015
Take home message
Wheat breeding won’t solve every problem facing growers, but it is a key component of continued wheat industry profitability. Excitingly, DNA testing is already increasing rates of variety improvement and is starting to open up opportunities to tackle traits that were previously placed in the “too hard basket”. Previously it was not feasible for a breeder to add new traits while focusing on improving the essential traits of yield, quality, and disease resistance. New technologies in breeding now make adding new traits while also enhancing rates of genetic gain for yield, quality and disease resistance possible. There are however still genetic and resource limitations. It is practically impossible to have everything, so where do we start? So what should be the targets going forward? How important is rust resistance vs weed competitiveness? What about quality vs long coleoptile for moisture seeking? What do you want?
The role of wheat breeding
Since its inception, wheat breeding has assisted growers in the north to meet their quality, production and profitability targets. However with changing farming systems, the impact of cost-price squeeze, a rapidly growing world population and the potential impact of climate change, wheat breeding needs to deliver greater rates of improvement to growers. Many of the gains made by wheat breeding go financially unnoticed by growers. Improvements in end-use quality and a broadening of the genetic basis to rust resistance, protect the existing value of the wheat industry against competitors and nature’s challenges. They ensure growers profit margins do not reduce, but they don’t necessarily increase return. However growers (and consumers) also need to see varieties released that lead to improvements in productivity and profitability. So how can we achieve that?
End use quality and rust resistance have always been key strengths of the northern wheat improvement programs. More recently, the Narrabri based AGT breeding program has placed additional emphasis on grain yield, crown rot tolerance and root lesion nematode tolerance. This strategy is now starting to pay dividends for growers, with the release of varieties such as Mitch and Suntop, which set new standards for grain yield in the northern region.
It’s not just the variety that matters, but how you use it.
Once a new high yielding variety is released, is that the end of it? Should breeders wipe their hands and move on to the next thing? Or are there more gains that could be achieved by breeders and agronomists working together to develop management practices tailored to each variety? For example, in 2014 many farmers would have started growing the new high yielding variety Suntop. This variety offers a great package to farmers in the north. It has high quality (APH), broad disease resistance and is higher yielding than any other wheat in its class (Table 1).
Table 1. The relative yield (from 2008-2013 NVT, % trial mean) and disease resistance ratings (from NSW sowing guide) features of five wheat varieties bred for the northern region.
|
Suntop |
Dart |
EGA Gregory |
Spitfire |
Sunvale |
NE NSW |
116 |
102 |
110 |
104 |
99 |
NW NSW |
114 |
101 |
109 |
104 |
98 |
SE QLD |
108 |
99 |
105 |
103 |
99 |
SW QLD |
111 |
98 |
109 |
103 |
99 |
Stem Rust |
MR |
MR |
MR |
MR |
R |
Stripe Rust |
MR |
MR |
MR |
MR |
MR |
Leaf Rust |
R |
MR |
MR |
MS |
MRMS |
Yellow Leaf Spot |
MSS |
MS |
MSS |
MSS |
MSS |
Crown Rot |
MSS |
MSS |
S |
MS |
MSS |
RLN Tol |
MT |
MI |
MT |
MTMI |
MTMI |
RLN Res |
MR |
MSS |
MS |
MS |
MS |
Black Point |
MR |
MRMS |
MS |
S |
RMR |
But with a big jump in yield, comes the need to modify or adapt management practices. As yield increases, protein concentration is diluted and more nitrogen (or timely application of nitrogen) is needed to maintain APH protein levels. Alternatively, growers may decide that they are better off accepting AH with Suntopand save the cost of added nitrogen. Last year, in conjunction with the help of AMPS Agribusiness, AGT ran a trial specifically aimed at asking; what nitrogen application regime will lead to the maximum return for the growing number of Suntop farmers? In Figure 1, we see that as expected, the yield of Suntop increases (by ~0.8t/ha) with the application of nitrogen (100 units). However more importantly, the manner in which the nitrogen is applied can be manipulated to suit the objectives of each farming business. In the 2014 trial at Narrabri and Rowena, delaying nitrogen application reduced the risk of high screenings and increased protein content relative to the 100% upfront nitrogen application treatment. Grain yields were lower when nitrogen was delayed, but depending on the price premium of APH over AH, the higher protein achieved by delayed nitrogen application may be the more profitable option. The use of late (during flowering) foliar applications of N could be considered to specifically target APH in Suntop.
This nitrogen application trial is just the start. Over the next few years, AGT will be increasing its investment in agronomic trialling in order to generate data to assist growers with decisions such as: time of sowing, sowing rate, disease management and fertiliser management. When combined with existing farm management strategies and new variety adoption, these variety specific practices should be another source of increased profitability for the northern region.
New technology: is DNA testing a game changer?
New technologies, particularly in the realm of DNA testing, are already impacting on breeding effectiveness. Whilst the effect of DNA testing has already been dramatic, it is the potential that it offers over the next 5-10 years that may see a paradigm shift for wheat variety development. Up until now, we have used molecular markers (ie DNA fingerprinting) to select for relatively simple traits such as rust resistance, acid soil tolerance and basic end use quality, earlier in the breeding process (which take 8-10 years). As the price of DNA testing gets cheaper, and as we develop new knowledge about the genetic basis to more complex traits, we can begin to expand the application of this technology. Within two to three years, we expect to be able to use DNA breeding tools effectively for improving traits like crown rot tolerance, root lesion nematode tolerance, baking quality and even grain yield.
This change will require greater financial investment by plant breeding companies, but should lead to a greater rate of genetic gain for growers. It may also allow us to take on more traits, but regardless of the technology we have access too we cannot add every trait, or in fact many traits, so it is critical to prioritise the traits we can add, but which ones? This is where we need grower input.
So what do we focus on?
When prioritising a set of target traits, it is a relatively straight forward process when the economic value of a trait is known. But what about traits where the value is either farming system dependent, or where the value is observed only in subsequent crops, or where the value is associated with an increase in risk?
In addition to highlighting some breeding traits that might be targets into the future, this presentation will use TurningPoint® to get your response to the question “what traits should we focus on”?
Summing it up
- Breeder’s are constantly adopting new technologies which will increase the rate at which we can deliver benefits to growers into the future.
- Clear communication between growers and breeders will ensure that breeding objectives will align with farming objectives.
- Short term gains can be made by mixing and matching variety with agronomy to maximise productivity and profit, while limiting risk exposure to each farming enterprise’s business plan.
Acknowledgements
AGT would like to thank all the growers, agronomists and researchers who contribute to the science of wheat breeding through conversation, suggestions, research and access to farm land for trials.
Contact details
Haydn Kuchel
Australian Grain Technologies
Perkins Building, Roseworthy Campus, Roseworthy SA 5371
Ph: 0428 817 402
Email: haydn.kuchel@ausgraintech.com
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