Targeting elusive genetic qualities in wheat
When wheat breeders set out to develop a new variety of wheat, they are targeting key quality attributes, including desirable bread baking qualities, flour with better water absorption, high milling yields and higher protein content. The problems with these key attributes, as is the case with many genetic traits of economic and biological interest in wheat, is that they are controlled by multiple genes.
Traditional wheat genetic studies (which only involve two parent varieties), have limited ability to define the genes determining key traits. In some cases they produce results which may reflect the parent varieties but are not applicable to use in a commercial scale. A new approach was needed to overcome these inherent constraints of existing approaches to identifying desirable plant qualities.
Identifying genes across multiple parents to pinpoint desirable traits
Our new approach, known as MAGIC (Multi-parent Advanced Generation Inter-Cross) allows the identification of genes controlling quantitative traits, such as loaf volume, by crossing different combinations of multiple parents. The results of these crosses are plants that have a genome which is a mosaic of their multiple parents.
MAGIC has multiple advantages compared with existing approaches, as it permits a more precise identification of genes that are responsible for wheat traits such as superior bread baking quality. Even genes with minor effects can be pinpointed.
Standard crosses (between two parents) have little recombination and show a poor correlation between the diversity found in the DNA (genetic diversity) and the diversity of the observable characteristics displayed by the plant (phenotypic diversity).
Because the MAGIC populations have a large number of individuals, and are the product of numerous generations of inter-crossing the original founders or parent plants, scientists are able to more accurately identify the genes underlying important traits.
Faster, more efficient wheat breeding
MAGIC has the potential to increase the speed and efficiency of breeding and will have a direct impact on the production of farms as well as the ability to change the way scientists identify the genes that control characteristics such as quality and disease resistance.
MAGIC is enhancing our understanding of the underlying genetics behind wheat quality, which is crucial for the improvement of crops and to help ensure Australia's continued success in the highly competitive global wheat markets.
In addition, this work is also providing Australian wheat breeders with more accurate DNA markers for the genes responsible for wheat quality. Just as importantly, they can also be applied across a wide range of characteristics important in wheat production such as seedling establishment, pre-harvest sprouting and disease resistance. MAGIC can also identify genes that are responsible for traits such as transpiration and heat tolerance, enabling plants to be bred with improved resilience to events such as drought.