Most of us eat grains every day – in bread, cereals, biscuits or pasta. In recent years, with gluten intolerance on the rise, wheat has been getting bad press. But how much do you know about this grain that forms such a significant part of our diet, and how has the wheat we eat changed over the centuries?
The era of the landrace
Wheat has been cultivated for more than 10,000 years, beginning in the Fertile Crescent and arriving in the UK around 5,000 years ago. Milling wheat for flour only became common in the 12th century, but by the turn of the 19th century, wheat was the UK’s most significant crop grown for human consumption. However, this wheat was very different to the crops that fill our fields today – the ears would tower over our modern dwarf varieties, commonly reaching 160 centimetres tall, and with great genetic diversity. These ‘landrace’ varieties were created by generations of natural selection and farmers saving diverse seed year after year. Over time, the landrace would become adapted to the specific soil and climate of the region, as the genotypes that do best in those environments became more prevalent. However, the pursuit of higher yields and industrialisation of agriculture over the past 150 years has meant these ancient varieties have been lost from our fields and all that remains of these traditional landraces is a handful of seeds that make up a series of entries, known as accessions, in gene-banks around the world.
Selecting the best
“Around the mid-1800s, the first plant breeders realised that if they saved the best ears out of the landrace they got single varieties that yielded higher, but weren’t as diverse,” explains Ed Dickin, a keen grain breeder who lectures in crop production at Harper Adams University. The first of these ‘seedsman’s’ varieties, such as Squareheads Master, were developed in the 1860s; measuring in at around 130 centimetres, they had a shorter and stiffer straw as well as a significantly higher yield.
At a similar time, around the 1870s, the UK began importing more wheat from Canada. “The millers started using roller mills, and roller milling works well with a hard wheat with a thick bran, as the bran is easily separated from the white flour stream,” Ed explains. This, combined with the rising demand for white loaves to make the sandwiches of the increasingly industrialised workforce, meant bakers were also keen on the higher protein levels of the imported wheat.
The laws of inheritance
Around 1900, the work of the monk Gregor Mendel was rediscovered. Mendel had worked on the ideas of genetics and the laws of inheritance at a similar time to Darwin, but it wasn’t until the turn of the 20th century that this work was applied to the breeding of wheat. It was discovered that although imported Canadian grains didn’t produce a good yield in our climate, they still produced high protein grain, and the newly formed Plant Breeding Institute (PBI) set about capturing this trait by crossing it with some of the British varieties.
A key part of wheat genetics is that the plant is self-pollinating, meaning the pollen from the anthers falls onto the stigma within the same flower. To cross varieties, breeders must remove the male anther part of a wheat flower before it produces pollen, then once the stigma has matured, introduce pollen from the plant they wish to cross the wheat with. This process, known as hybridisation, produces a first-generation F1 plant that will be a genetic cross of the parents. However, the next generation, an F2, will have huge diversity because of the large number of genotypes created by the hybridisation process. To produce a stable variety, multiple generations of self-pollination and careful selection of plants is required. This is the method the PBI utilised in 1916, crossing the Canadian Red Fife with a low protein British variety to produce Yeoman, a hard wheat that measured in at around 110 centimetres tall.
While this breeding improved the bread making properties of homegrown wheat, the UK was still importing much of its bread wheat – a trait that continued until the 1960s when a trio of changes came into place. The first was the advent of the Chorleywood Bread Process, an industrialised process that could utilise lower protein wheats. In combination with this, the Plant Varieties and Seeds Act of 1964 allowed breeders to collect royalties from the seeds they bred, and the UK’s entry into the European Economic Community (EEC) meant that there were tariffs on the import of Canadian wheat – consequently, the use of British wheat began to increase.
The quest for higher yields
Since the 1980s, breeders of milling wheat have been increasingly focused on their largest market – white sliced bread – meaning that the modern varieties such as Skyfall are bred for this purpose, producing high yields, of sufficient protein levels for roller milling and the Chorleywood Bread Process.
Baker, miller and grain grower Andy Forbes points out the wider impact this had on the wheat grown: “Wheat used to be tall to out compete the weeds, but if you put chemical fertiliser on it to increase the yield, there’s a risk it will fall over, known as lodging. That’s one of the main reasons shorter varieties were grown, but once it’s shortened, the wheat doesn’t shade out the weeds, so farmers started using herbicides to get rid of weeds.”
One of the global figures at the heart of developing these new wheats was Norman Borlaug, who spearheaded the so called ‘green revolution’. But while the grain volume produced by his semi-dwarf crops was significantly higher, the use of nitrogen fertiliser to drive up yield, and herbicides and fungicides to manage disease, has been shown to have an impact on soil health, and the genetic homogeneousness of modern wheats also means they’re highly susceptible to disease. “By growing the pure line varieties, you get a high yield, but you lose the ability to adapt,” Ed explains. “The yellow rust population, like any other diseases, is a diverse population, so the parts of the population that can overcome the plants’ resistance become more dominant. But the modern wheat can’t adapt because it’s a monoculture, so the breeders are constantly having to bring in new sources of resistance to address this. It’s the breeders’ treadmill.”
The pressure for high yielding wheats is also driven by the way the commodity market operates. Most grain in this country is sold via a trader, who acts as a middleman between farmers and buyer – whether that’s a flour mill, grain exporter or feed mill. The traders set the price based on the global market, taking the sale price out of farmer’s control. “Producing a commodity means the cost of production is the only thing a farmer can reasonably expect to influence,” farmer Fred Price from Gothelney Farm points out. “As a price taker, this creates an inevitable bias towards increasing yield in an attempt to reduce cost of production.”
Fit for purpose?
From the agroecological farmer’s perspective, modern wheats don’t grow well in a low input, organic system; quite simply, they’re designed for a different growing system that is reliant on external inputs. “Organic farmers don’t have access to or want to use these chemicals,” Andy explains. “But they also don’t have access to wheats that don’t need these inputs, or that are suited to their local climate.”
“In a regenerative farming system, I’m looking for flavour and resilience,” says Fred. “And by resilience, I mean varieties that have genetic diversity and traits that put crop resources into physiological traits such as root density and crop height that buffer fluctuations in climate and pathogen pressure. These, in theory, are going to impact the yield. But there is a trade-off between resources being put into yield or traits which improve resilience: height improves weed competition, restricts fungal spread upwards through the plant, genetic diversity restricts susceptibility to particular strains of infection, and so on.”
In addition, there has been an increase in demand for sourdough bread, as well as a rise in awareness about the health benefits of whole grains. But the modern wheat we grow in this country is suited to neither market. “Thick branned wheat that’s suitable for roller wheat is no good for stone milling,” Ed points out. “You want a variety with a thinner bran because all the bran is going to go in the flour.” Similarly, the gluten levels in the flour will be different than those used in Chorleywood bread, meaning these flours aren’t ideal for sourdough baking.
It’s clear our modern wheats, bred for high input farming systems and roller milling, aren’t suitable for agroecological farming or whole wheat baking. So, what grains should we be growing? How can we rebuild genetic diversity in our wheat? And can we re-localise our supply chains?