Arguably the oldest grain in cultivation, wheat has been grown for upwards of 11,000 years. The first evidence of cultivation and consumption is believed be in and around Turkey which coincides with the “fertile Crescent,” also the birthplace of domesticated barley, lentils and even sheep among many others well known crops and livestock we consume today.
Like barley, wheat is grown all over the world, from the the relatively wet English countryside all the way to the dry, hot regions of Western Australia. While it does have a variety of uses, the majority is used by the baking industry, which is why the majority of wheat grown “Triticum aestivum” is known as bread wheat. There is also another widely grown type of wheat called durum wheat, which is predominantly used to make pasta. These varieties differ in the intrinsic flour attributes such as gluten and protein content.
In Australia wheat is by far the “bread winner” as far as area sown goes, having been sown in over 11 million hectares in recent years, around 9 million more than the next largest crop which is barley. This huge annual production of wheat equates to a total production value of typically around $6 billion, which is more than the combined total of the other 4 major crops grown in Australia (barley, oats, grain sorghum and cotton).
Wheat varieties grown in Australia are typically sown in early may and harvested in November/December. They have similar growing requirements to other crops although wheat in comparison to oats or barley is less tolerant to frost. Sowing generally occurs in a tight window either before rains (dry seeding) or immediately following the break of a season which is a characterised by a decent rainfall event. While ANZAC Day is broadly defined as the start of the sowing season, the date will vary based on rain.
Like any crop, wheat is continuously monitored throughout the growing season to ensure the best possible growth. Maintaining plant health may require the use of fertilizer or reducing weed burdens by spraying herbicide. Interestingly, more fertiliser does not a bumper crop make. Applications of nitrogen in excessive quantities mean that the wheat plant becomes increasingly leafy and wasteful of water and available nutrients. Farmers need to match fertiliser requirements with wheat growth stages and environmental conditions to ensure that the maximum amount of grain is produced for the same amount of leaf area. This is called the harvest index (yield divided by total plant mass).
Diseases and insect pests are also an important stress to watch over because severe infestations can significantly reduce yields. However, the Australian dry climate and typically low humidity in growing areas mean that disease pressure is low compared to Europe, where they may spray up to 15 times a season.
Assuming all goes smoothly throughout the growing season, there should be a high yielding wheat crop (typically between 2-6 tonnes/hectare) to harvest later in the year. As a small nation with a low domestic consumption of wheat, Australia exports the majority of the annual wheat crop to populous countries such as China and Indonesia, where there is a huge requirement for wheat and other grains.
Bread wheat can be classified into two categories: hard and soft. Hard wheats contain more protein and are better suited to making bread. They also attract a premium over other wheat grades because manufacturers prefer higher protein overall. Soft wheats on the other hand have lower protein content and better suited as flours for cakes and biscuits. The lower protein content of soft wheats produce a product that is more crumbly and “lighter” which is why it is preferred in cakes and other goodies.
(3) Wheat breeding
Since the arrival of wheat as a crop those thousands of years ago, wheat has undergone massive changes. Interestingly, wheat is a result of the spontaneous crossing between three separate grass species. It is this early crossing event that explains why common bread wheat has three genomes A, B and D (known as triploid). Early humans recognized the superiority of this new species compared to others and either actively or indirectly began the process of directional selection for a wheat that yielded more and grew better in the condition they faced. Common sense suggests that early humans would have chosen to grow the plant that gave them the most in the previous season!
Fast forward to nowadays and the process of breeding is largely unchanged from those early days, although the processes by which we choose to improve wheat has changed considerably. A large focus of current breeding is via the use of genetic resources and information to improve wheat varieties in a rapid and efficient fashion. We can now use molecular markers linked to important traits (e.g. disease resistance) and screen germplasm with these markers to determine which individuals are likely to have resistance to a certain disease for example. Further improvements in the breeding space are moving towards the genome engineering sphere which has both its pros and cons. There are many methods for genetic engineering and wheat is one of the many crops that these news breeding technologies are being used on to improve production.
Fun fact #1: Wheat is a product of a cross from three separate species, if this were to happen today in a lab, the product would be classified as GM. But because it occurred naturally thousands of years ago people may choose to forget this important point from a regulatory perspective.
Wheat as a major global food and feed crop has a large amount of history and information surrounding its production, processing and breeding. The ABARES website is a great start to finding out how important wheat is towards the Australian economy and how much is produced in comparison to other crops. There is also a lot to consider from a farmer’s perspective about what variety to choose so the National Variety Trials program is a good step towards learning what varieties are suited for what regions.