Change in direction for cereal protection

While investment in the development of new chemical actives continues globally, the intensiveness of this search is decreasing as new product development becomes more expensive and pesticide control legislation sets ever-increasing control standards.

This has forced a move away from the search for new chemical actives towards R&D to help develop new genetics-based solutions that will be delivered through the varieties of the future.

An increasing, and increasingly wealthy, population around the globe demands more wheat and, in some parts of the world, land is also under pressure to grow biofuels.

In Ireland, we are well positioned to capture increased crop values that are likely to result from the growing demand for food, and we are also relatively tolerant of the negative effects of climate change.

Ireland benefits from a relatively good tillage infrastructure which is well adapted to technology translation, and with well organised routes to market.

However, Irish growers are challenged year-on-year by agronomic, environmental and financial hurdles, some of which are hard to predict. Successful tillage farmers of the future will need innovative technical solutions to ensure sustainable profits are realised. In the crop sector some of the main hurdles to production include:

Agronomic

With technical advances in crop protection products slowing down so markedly, it is generally accepted that the next great advance in crop production will stem from improved genetics.

Recent innovations, such as the use of molecular markers, have shortened the timeframe for selection of new varieties and allowed specific traits to be selected without relying on genetic modification – an important consideration in Europe presently. Pest resistance is a worsening issue in the UK and is likely to be a problem here also and we must not be complacent.

Climate

Wildly fluctuating weather patterns have caused challenges in recent seasons, by interrupting application of pest, weed and disease control measures and encouraging previously lesser-known pests and diseases to take hold.

In addition, the flowering and pollination processes in crops may be negatively affected and thereby reducing yields. Other environmental effects can occur which impact production, such as excessive soil compaction.

Legislation drivers

The new EU legislation 1107/2009 has radically impacted the approvals process for new crop protection chemicals, and numbers of new actives are declining on a year-by-year basis.

The use of new zonal approvals is causing significant delays and this, together with a move from risk-based to hazard-based approval mechanisms, means older chemistry is being lost and manufacturers are thinking twice about bringing new products to market.

Environmental legislation, such as the drinking water directive, may also impact the future availability of certain key actives, and the nitrates directive continues to restrict the use of nitrogen.

If nutrient use efficiency of crops remains unchanged, higher nitrogen and phosphate inputs will be required to increase yields and meet the food challenge demand, with consequential impacts on the environment.

There are tensions between food production and farm ecosystems, CAP reform and greening measures. The requirement for farming to contribute significantly to the reduction of Ireland’s carbon footprint is an additional challenge, although invariably higher yields lead to lower greenhouse gas emissions per tonne of grain. The reluctance of Europe to embrace genetic modification on environmental / political grounds will reduce Irish farmers’ ability to compete.

Financial

Despite recent increases in crop values, prices remain extremely volatile and this makes financial and business planning a real challenge for tillage farming.

In addition, fertilizer prices have increased significantly, reducing farm margins. The increasing unpredictability of yields, due to factors mentioned previously, means challenges to cashflow will be an increasing factor.

Global production, marketing and utilisation of cereals will undergo significant change in the next decade. Production is likely to increase by 1% to 2% per year. Consumption of grains will grow, particularly in Asia.

The increasing demand in Asia will be met, at least in the short to medium term, by imports from the United States, Australia and Europe rather than increased domestic production. With the development of agronomy capability in some eastern European countries, the total available grain in the EU will probably increase.

In this part of the world, it is likely that, in the short term, demand for feed grains will increase. Cereals could also replace, to some degree, consumed forages, especially grass silage made from second and third cuts which have relatively low quality.

Clearly, there is a considerable challenge to increase production efficiency and enhance the value of produce in a scenario of volatile prices and decreasing EU compensating payments.

Genetics for the future

Reducing unit production costs for cereals is of paramount importance to maintain competitiveness. Adoption of new varieties, and developing management practices which will exploit their genetic potential, will be crucial if Irish tillage farmers are to survive long-term in crop production.

Evaluation of new varieties which emanate from plant breeding sources in Britain and Europe will be key to this success. And it will be equally important to develop appropriate production technologies to exploit their genetic potential.

Further evaluation of hybrid wheat varieties, which have potential for 10% to 15% greater grain yield than conventional wheat, offers some potential and it is good to see renewed interest in hybrid wheat by the main plant-breeding companies.

The identification of winter wheat varieties, which possess agronomic traits important to Ireland, needs to be exploited, e.g. improved disease resistance (Septoria, Fusarium); suitability for early sowing; suitability for second wheat position in the rotation etc.), as well as enhanced nutrient use capability.

There will also be potential for the identification and management of varieties for appropriate end-use markets.

New seed traits

The search for seeds with unique traits offers considerable potential and is a new and exciting research area globally. This is now feasible as breeders have the tools and technology required to make significant progress.

As a result, we are likely to see significant improvement in the production of seeds with unique traits using techniques such as novel germplasm, genomics, mutations, transgenics and using phenotyping /statistics/bioinformatics on a scale that has not been seen before. This is now happening in the US and in Europe, including the UK.

We also need to look at traits/cultivars/hybrids that are environmentally flexible so that they can withstand a wide variety of factors that limit yield.

Breeders are now striving to exploit this to the best possible extent using effective selection, especially by tying molecular markers (which have become very cost effective) to phenotypes (visible characteristics). The developments in laboratory automation and interpretation of complex data sets is assisting this effort greatly.

The stacking of traits into wheat varieties offers an exciting opportunity now that marker-assisted selection techniques are routinely used by the major plant breeding companies.

All of the major agrochemical manufacturers have moved into seed and crop genetics and the development of new traits will benefit both the agronomic attributes and end-market values of cereals.

It is therefore likely that we are going to see significant developments in seed traits that will benefit the cereal sector in the longer term.

Important techniques

To achieve success in the delivery of new and novel traits will require that new tools be used in the production and selection of these genotypes. We will need to be able to identify a greater amount of the natural diversity that exists in our cereals and then concentrate on the ones most likely to deliver real benefit to the grower and consumer.

We must further exploit the genetic diversity of wheat. While scientists have made great strides in wheat breeding, there may be unknown genes that could push wheat yields up further and these are actively being researched.

Wheat scientists have launched a worldwide search for genetic diversity in order to find such new genes and I am hopeful that this will prove beneficial in the long term.

We must also make better use of scientific selection criteria to identify useful traits, e.g. marker-assisted selection. Breeders need to utilise new technologies that will help identify the best plants for crossing much earlier in the breeding process, thus speeding it up.

Prior to the development of markers associated with genes of known interest, plant breeders selected new offspring primarily on phenotype, i.e. what one could observe, and this was mainly done in the field.

But nowadays, it is now possible to select lines which carry valuable traits from segregating populations in the laboratory, without field selection. A library of valuable markers associated with known valuable traits has now been collated and these markers are being used to increase the efficiency of selection for valuable characters.

Already, physiological, quality, disease and pest traits are being assessed in breeding programmes. While this technology is still in its infancy, the potential is high.

Future seed with novel traits

While these new sciences could deliver a significant range of new traits, it is generally thought that developments in new seed traits are most likely to be successful in the following areas.

Root, stem, foliar and ear diseases have major potential to reduce the yield and quality of cereals. Resistance to Septoria tritici is of very high importance in Ireland with even low levels of the disease resulting in reduced yields and grain quality.

Recent research by Teagasc has shown reduced sensitivity to the chemistry currently in use for disease control and we must look for additional strategies for keeping crops disease free.

We will continue to rely on a combination of genetic resistance and chemical control for optimal disease and pest control. In the past 20 years, a vast array of fungicides have been developed which help to combat the worst effects of the prevalent diseases.

But resistance, as discussed previously, coupled with the threat of potential loss of key active ingredients, means this subject area needs a constant focus.

In addition, aphid resistance is beginning to cause issues in cereal crops, and alternative control methods for BYDV need to be addressed.

Significant progress continues to be made with disease resistance using conventional plant breeding strategies. Screening newly bred material within the Irish environment is now taking place and this should also help.

With new gene stacking technology, the opportunities for new varieties with enhanced levels of disease resistance are significant. While diseases such as Septoria tritici and Eyespot represent real threats for the Irish grower, standing power and the ability to withstand wet weather at harvest are also major concerns.

A high proportion of the human and animal diet begins with seeds. So improving the seed composition can contribute to improved nutritional quality, with significant benefits for all. For example, work carried out some years ago by Bill Angus, a well-known wheat breeder, identified varietal differences which would be of benefit to poultry producers.

This has resulted in the exclusion of certain wheat varieties (which carry the 1B/1R wheat/rye translocation) from the dietary make-up of certain feed producers.

While the problems associated with this undesirable trait have been resolved by the use of enzymes, this results in additional costs. And in the future, such inclusions may come under greater scrutiny as pressure grows to reduce additives. We are also likely to see other opportunities to create altered composition for different end uses, e.g. high phytase wheat.

Phytic acid is the major storage form for phosphorus in plants – approximately 80% of the phosphorus in cereal seeds is present as phytic acid.

Unfortunately, phytic acid is extremely poor as a dietary source of P, both in humans and in animals. This is especially the case in monogastric livestock which, like humans, lack phytase enzymes in their gut to break down phytic acid.

Moreover, phytic acid chelates vital mineral nutrients, in particular iron and zinc but also calcium and magnesium. The iron and zinc deficiency of cereal grain diets affects millions of people in developing parts of the world and this is largely due to phytic acid.

In developed-world agriculture, phosphate-rich discharge from pig, poultry and fish farms is a major environmental pollutant.

As well as the human and environmental afflictions caused by phytic acid, and because the phosphate in cereal grains is so unavailable, livestock feed is either routinely supplemented with inorganic phosphate or, alternatively, a manufactured microbial phytase enzyme is added to the diets to break down the cereal phytic acid after ingestion.

Both supplementation approaches are costly and global inorganic phosphorus sources are rapidly being depleted. An alternative solution could be to reduce the levels of phytate and increase the levels of bio-available phosphorus in cereal seeds.

Consequently, the need to add synthetic phytase to animal feed could be drastically reduced or avoided altogether. Transgenic soyabean and canola (oilseed rape), bred to over-express phytase, have been shown to reduce phosphate discharge from poultry and pigs by 50%.

Scientists have already identified novel genetic germplasm from which to breed for enhanced seed phytase. They have also developed molecular markers suitable for low-cost, high-throughput genetic screening.

Scientists have also identified the location of these genes on the chromosomes of wheat and barley and this will facilitate marker-assisted breeding of the optimal conformations of phytase genes.

Consequently, this information and related breeding technology opens the way to improved diets for monogastric livestock.

It will also bring significant economic benefits to animal feed regimes through reduced additive costs, as well as environmental benefits through reduced phosphate pollution. It will also lead to enhanced nutritional status of humans who consume grain-based diets.

Grain yield is very strongly influenced by the availability of water but lack of moisture is seldom an issue in Ireland. However, in Britain and in other parts of Europe, there are now pressures on plant breeders to select varieties with improved water use efficiencies.

In addition, breeders are selecting for increased tolerance to a range of other abiotic stresses (heat, drought, nutrients, toxicities, acidity, alkalinity, salinity, etc.), as well as the ability to select plant types that can penetrate strong soils.

Nitrogen is a big driver of yield and its use efficiency will have to increase in the longer term. There has been little work on the efficiency of different wheat varieties in terms of nitrogen use. However, we must now begin to seek out variability, which may help to improve this, but I acknowledge that this is a long-term proposition.

In summary

With technical advances in crop protection slowing down so markedly, it is generally accepted that the next great advance in crop production will stem from improved genetics.

Recent innovations such as the use of molecular markers have shortened the timeframe for selection of new varieties and allowed specific traits to be selected without relying on genetic modification.

Plant genetics and plant breeding will, in the future, lead to new varieties with novel seed traits. These traits will include seeds with higher yield potential and with enhanced levels of disease resistance.

They will also have altered composition for specific end uses. In addition, we are likely to see seeds with greater resource acquisition capability (e.g. nutrients, water).

Seeds of the future will have increased tolerance to a range of other abiotic stresses (heat, drought, acidity, alkalinity, salinity, etc.).

Despite the potential that lies ahead, there is a growing awareness that these new targets, which are now being set, are far more complex and difficult to achieve than those established in the past, where yield was of prime importance.

For Irish growers, the identification of winter wheat varieties which possess important agronomic traits need to be exploited, e.g. improved disease resistance (Septoria, Fusarium); suitability for early sowing; suitability for second cereal position in the rotation etc.), as well as enhanced nutrient use capability.

There will also be potential for the identification and management of varieties for appropriate end-use markets.