Genetics can boost crop potential and chemistry can protect it. But both sectors face challenges as well as opportunities as they strive to lift farm productivity, delegates heard at the latest Farmers Club Monday Evening Lecture.
According to Dr Tina Barsby, CEO of NIAB, there have been enormous advances in plant breeding in recent years, with technology being used to transform processes and bring faster results.
“Things have changed,” she stressed. “That’s due to an increased emphasis on using natural variation to find diversity, as well as the advent of cheaper genome sequencing. In addition, IT can now deal with much of the mundane work.”
As cheaper and faster methods of sequencing genomes have been developed, publication of genome maps has occurred and knowledge has expanded, she pointed out.
“The first draft of the wheat genome was published in July 2014, and although the full sequence is only available for one of the three chromosome sets, it was a huge achievement. Remember that the wheat genome is massive – five times the size of the human genome.”
New sources of wheat genetic diversity come from mutants, related species and synthetics, with all sources being used to add to the genetic melting pot, Dr Barsby revealed.
“There were two chance events that occurred in the long history of modern wheat. Both involved hybridisation with wild relatives, emmer and goat grass.”
As a result, pre-breeding lines have been resynthesised with wild goat grass at NIAB, to create more diversity, she reported. “Wide crossing works well. With our synthetic wheat crosses, we have seen yield increases of around 30%.”
While some of that yield potential will be lost once it is in a commercial line, which can take up to ten years to produce, there are other benefits too, she said. “They seem to hold yield at lower nitrogen levels.”
As well as synthetic wheats, work with MAGIC wheats is on-going. “This involves crossing and crossing to get lots of variation, so it really stirs the pot and improves the speed and efficiency of wheat breeding.”
However, Dr Barsby highlighted hybrid wheat as the next big development, with FI hybrids already in the UK testing system.
“They give improved performance over conventional wheat, with lower inputs used and when under stress,” she said. “The first of these is likely to be sold in France, but the UK is not far behind.”
Otherwise, various breeding strategies are available to commercial companies, with another new development known as genome editing on its way.
“Currently, we have marker-assisted breeding, accelerated breeding and genomic selection – all of which can be used to select specific characteristics or reduce the time taken for generations to be produced.
“But the step change will come from genome editing. This is like using a pair of molecular scissors to remove, insert or replace a genetic sequence, without leaving a footprint.”
As such, it can be used to make targeted changes, with the resulting plants being indistinguishable. “It isn’t the same as GM, so it’s unlikely that same crop regulation won’t apply.”
In contrast, new active ingredients to use in agrochemicals are becoming few and far between, reported John Peck of BASF, who pointed out that the scrutiny that plant protection products are subjected to means that they have to meet 800 requirements.
“As a company, we’re testing more than 100,000 molecules every year,” he revealed. “It’s a long-term process, with a new product taking ten years to develop. The European market can be particularly challenging, which is why there’s been a fall in the number of substances targeted at Europe.”
This initial screening looks for various factors, he continued. “Very reliable action is a major requirement, but the molecule must also be well-tolerated by cultivated and beneficial organisms.
“In addition, it must have favourable toxicological properties and strike the right balance between rapid degradation and length of activity.
“Finally, it needs to come in a user friendly formulation and bring added value to producers and users.”
Alternatives to new agrochemicals include diagnostics for better targeting, precision application and seed solutions, such as coatings, he suggested.
“With the latter, regulatory aspects have to be taken into consideration,” highlighted Mr Peck. “It is becoming very difficult to get new seed treatments registered.”
Other developments with a good future include biological products, involving the use of pheromones, parasitic wasps and bacteria, to name a few, he continued.
“There has been success with some of these. Entomopathogenic nematodes are a good example – they are specific in infecting slugs and some insects, and they act as a vector for bacteria.”
Once the nematodes penetrate the target pest’s body cavity, the bacteria they carry destroy the pest.
“It’s a system which works well, but it is expensive and the nematodes have a shelf-life of 3-4 months. So it’s not the same as having slug pellets in the store, in case you need them.”
In the same way, lure-and-kill technology is being trialled in pulse crops, for the control of bruchid beetle and pea and bean weevil. “In this system, a pheromone is used to attract the pest, which is then infected with bacteria.”
Finally, Mr Peck mentioned Bacillus subtilis, a broad-spectrum fungicide and bactericide, with anti-fungal properties.
“It improves plant health and promotes growth, but needs to be used in conjunction with other techniques to get the best from it."