INTERNATIONAL WHEAT QUALITY CONFERENCE

MANHATTAN, KANSAS, USA
May 1997

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OPENING SESSION KEYNOTE ADDRESS *

For many years it has been an elusive task to provide a precise definition as to what constitutes quality in wheat. Each country has its own traditions in bread and other bakery products. Quality will mean different things to a miller, a baker, a grain handler or a plant breeder. As the baking industry becomes increasingly specialized, specific qualities are sought. Even among those wheat varieties generally recognized as having desirable quality traits, the influence of environment can be substantial, and this necessitates a high level of skill on the part of grain buyers to survey the current year's crop and blend the wheat to obtain a suitable balance for a specific end use. This genotype x environment effect on quality also limits the capacity of end users to source an identity - preserved wheat from a narrow geographic area. There is no universal definition of quality - it usually means conformity to several measurable characteristics which experience has shown to be significant in terms of end use. It also means consistency in the production of an end product. Plant breeders are primarily concerned with those quality traits that have high heritability and can be manipulated genetically, and we study their stability under a range of climatic conditions. Constraints of time, cost, and sample size usually necessitate the use of predictive tests during early generations, followed by milling and baking tests on advanced lines that have met a number of agronomic, disease and predictive quality criteria. The importance of communication among all sectors of the wheat industry has never been greater. New tools arising from biotechnology research have enabled geneticists to transfer specific genes among species and even genera, leading to regulatory issues that have to be addressed and concerns that need to be answered. This paper takes a multi-disciplinary approach to the key quality issues confronting the wheat industry today and addresses some future opportunities as our industry becomes more vertically integrated.

It is a pleasure to have this opportunity of addressing the International Wheat Quality Conference, and I would like to thank the organizing committee for their kind invitation. As you will have seen from the program, the committee has truly sought to represent all sectors of the wheat industry on an international basis, with emphasis on the need for understanding between the various disciplines. This is the primary reason for there being no concurrent sessions, and it will afford us the opportunity to collectively put the various pieces of the puzzle together.

Thirty years ago, as a young wheat breeder in what is now Zimbabwe, I submitted my first set of breeders samples for evaluation by the quality laboratories of a local milling company. The reports I received were not very flattering. There was clearly plenty of room for improvement in the breadmaking quality of our wheat varieties, and I came to understand that I could always rely on the cereal chemists to inform me of these deficiencies whenever the opportunity presented itself! I resolved there and then to study cereal chemistry so as to have a personal perspective as to what constitutes quality. When I arrived in Fargo, North Dakota in 1970 on study leave, I found that the first semidwarf Hard Red Spring wheat had been released, and the breeders and cereal chemists were not in a very good state of agreement. The cereal chemists had the notion that semidwarfs would destroy the U.S. HRS wheat industry and that the genes conditioning reduced plant height were somehow linked with unfavorable genes for quality. Clearly, there was room for improved communication. I believe that much has been achieved over the years to improve communication among all sectors of the wheat industry.

For many years it has been an elusive task to provide a precise definition as to what constitutes quality in wheat. Each country has its own traditions in bread and other bakery products. Quality will mean different things to a miller, a baker, a grain handler or a plant breeder. As the baking industry becomes increasingly specialized, specific qualities are sought. Even among those wheat varieties generally recognized as having desirable quality quality traits, the influence of environment can be substantial, and this necessitates a high level of skill on the part of grain buyers to survey the current year's crop and blend the wheat for a specific end-use. This genotype X environment effect on quality also limits the capacity of end-users to source an identity-preserved wheat from a narrow geographic area.

In 1947 Aitken and Anderson concluded their paper entitled "Conflicting Opinions on the Quality of Bread Wheats" with the following statement:

"The results of this investigation show that cereal chemists hold different opinions on what constitutes breadmaking quality and how it should be measured. The difficulties in reaching opinions on the merits of new varieties are all too apparent."

I would not be so bold as to suggest that 50 years later a similar problem remains. Suffice is it to say that there is no universal definition of quality; it usually means conformity to several measurable characteristics which experience has shown to be significant in terms of end-use. It also means consistency in the production of a specified end product.

Those of us engaged in the field of plant breeding are concerned primarily with those traits that can be manipulated genetically, and we study their stability under a range of climatic conditions. Improvements in our understanding of the effects of environment on protein solubility fractions, how these relate to quality, and how they vary among varieties has given us the opportunity to select for improved stability of quality. Constraints in time, cost, and sample availability usually necessitate the use of predictive tests during early generations, followed by milling and baking tests on advanced lines that have met a number of agronomic, disease and predictive quality criteria. New tools arising from biotechnology research have enabled geneticists to transfer genes among species and even genera, leading to a potentially large number of modified end-use products. This has led to a number of regulatory issues that have to be addressed and concerns that need to be answered. Never has the need for communication among all sectors of the industry been greater.

In addressing this broad topic of a global approach to wheat quality, I must acknowledge both the constraints of time and the limitations of my personal perspectives. Our Pioneer wheat program is targeted at a number of major wheat producing countries, and as an international company we are the custodians of a diverse germplasm base that encompasses several market classes of wheat. This germplasm base has to be deployed in such a manner as to maximize genetic advantages while conforming to the quality requirements of the local market. An understanding of local market needs, quality perceptions, and requirements for either the release or registration of varieties and hybrids is essential. In this discussion examples will be drawn primarily from Europe and the U.S. and the following topics will be addressed:

1. The diversity of wheat quality requirements;
2. Quality Councils as a forum for communication;
3. Current trends in quality improvement;
4. The potential for new food and non-food products; and
5. Changes in market requirements over the next ten years.

1. The Diversity of Wheat Quality Requirements

Our U.S. wheat varieties are divided into five market classes: Hard Red Spring, Durum, Hard Red Winter, Soft Red Winter and White wheat. Within each class there is a normal protein range and there are specified flour uses. In the past it was considered possible for the Federal Grain Inspection Service (F.G.I.S.) to assign wheat to one of the five market classes based upon geographical region and an examination of kernel characteristics. The later in particular was considered important when wheat was removed from its point of origin and placed in bulk storage at terminal elevators. However, as a result of crosses between classes, today's varieties do not conform to the traditional market classification based upon kernel characteristics. This has led to the development of objective criteria for assigning wheat to a market class and, while significant progress has been made, the process is still underway.

One consequence of the wheat classification issue was to raise the issue of whether there had been a decline in the quality of current varietal releases. The separate issues of classification versus quality tended to become merged as various quality parameters were examined that might be used as a basis for classification. However, separate studies of Hard Red Winter and Hard Red Spring wheat varieties by Cox et al (1989) and by Cholick (1985), respectively, showed no evidence of an overall decline in quality. In general, it can be said that plant breeders (together with their support teams) have increased yields, significantly reduced the risk of the wheat crop succumbing to a major disease, and have maintained an acceptable level of quality. While there is generally a negative correlation between yield and quality, it has been possible in many instances to increase yield while holding protein constant.

During the past ten years, we surveyed public institutions and private companies with bread wheat breeding programs in the U.S. The survey revealed that the first predictive quality tests are conducted anywhere from the F2 to the F5 generation (Table 1).

The tests include protein (NIR), hardness score, sodium dodecyl sulfate (SDS) sedimentation value, and mixograph score. Protein and hardness are important criteria for conformity to the market class. The SDS sedimentation test provides an indication of protein quality, and the 10-gram mixograph provides a screening device for water absorption and dough mixing properties in a very small sample of flour. Today the single kernel hardness tester is providing a more precise measure of hardness than bulk NIR, and the two gram mixograph is used by some institutions. The advanced generation tests are a combination of survey results and Wheat Quality Council tests; they represent those tests most frequently used and include some predictive tests.

  Table 1. Summary of predictive tests used by bread wheat breeders for quality screening of new lines in the U.S. and in Europe.

The tests listed for Europe in Table 1 represent a composite of several studies, and wide variation exists between countries and programs. In France we have made extensive use of the 10-gram mixograph and run approximately 3,000 tests on F5 lines prior to advancing material into multi-location trials. The glutomatic instrument has also come into more widespread use, and the scores correlate fairly well with French breadmaking scores. Machinability is a rather subjective test in that it relies on the opinion of the test operator in deciding whether a ball of dough produced in the mixing process sticks to the apparatus or not.

In the U.K., a new testing protocol has been in place for the past few years to assess varieties for inclusion on the Recommended List (Table 2).

Table 2. Tests used in assessing breadmaking quality in U.K. wheat.

These tests provide an assessment of the milling quality of the wheat, the baking quality under the standard Chorleywood baking process (CBP), the baking quality using different input speeds and mixing times on the spiral mixer, and the protein quality by analysis of the gel protein. Statistical procedures have been used to reduce the array of variables to more simple scores.

The Chopin Alveograph test (Fig. 1) is used to measure gluten quality as a predictive bread and biscuitmaking test and is widely used in France, Spain, and Italy.

A disk of dough is made from flour and water and is pressurized by a stream of air. The instrument measures the maximum pressure (P) required to blow a bubble of dough, and the time taken to burst the bubble (L). The former measures gluten strength and the latter measures extensibility. The value "W" is the area under the curve and a high W is associated with strong gluten required for bread flour. Strong Spanish wheat has an alveograph W of 400, while satisfactory French and British breadmaking wheat has values in the 150-200 range. A low P/L ratio indicates an extensible, weak gluten associated with a biscuit flour. The alveograph is not widely used in the U.S., with the Brabender Farinograph having wider applicability in the Spring Wheat region.

France used a graduated scale in its varietal registration process and rewards higher quality with a correspondingly lower yield performance requirement. Germany has made some efforts in recent years to simplify the number of quality classes that varieties are assigned to, and Austria is now moving closer to the German system following its entry into the EC. France permits soft textured wheat with high breadmaking quality, while most other countries tend to favor hard textured wheat, depending upon the baking process being used and the need for starch damage in the flour.

In 1992 the EC saw reforms in the Common Agricultural Policy (CAP). Previously, all types of wheat were eligible for intervention providing they met certain, fairly low standards of quality. The new intervention standards raise the quality of acceptable wheat and effectively bar feed wheat from intervention. The new standards for common wheat are shown in Table 3.

In the U.S. hard wheat for breadmaking constitutes over two thirds of the national crop. However, Soft Winter wheat (SRW and SWW) represents an important market segment and is used in a diverse array of bakery products. Soft wheat with favorable High Molecular Weight glutenin subunits also have satisfactory breadmaking properties and this is being evaluated by milling companies in the northeast. The diversity in soft wheat end-use makes it more difficult to assign scores based on a few predictive tests, and attempts are being made to better segment the market. At present, the distinction is made between pastry flour and a cracker and export flour, where the latter requires higher flour protein, a higher Alveograph W, higher Farinograph absorption and stability, and a longer mixing time.

Table 3. Intervention standards for common wheat in Europe.

2. Wheat Quality Councils as a Forum for Communication

In February 1997 the first joint meeting of the Quality Councils representing the three main classes of wheat in the U.S. (HRW, SRW, and HRS) was held in Kansas City, MO. The Council was originally founded in 1938 and has a distinguished history of evaluating wheat for milling and baking quality. Each council had held their respective meetings in the past, but the 1997 meeting brought together the broadest cross section of the industry with a common goal, namely to enhance the milling and end-use qualities of all classes of wheat. Although still under-represented by the baking industry, membership is growing and the goals of the Council include the following:

• To encourage broad participation by all members of the wheat industry;
• To identify desirable quality performance characteristics in new varieties of wheat;
• To emphasize the importance of communication among all sectors of the industry;
• To provide educational programs relating to continuous improvement of wheat quality;
• To encourage ongoing support for the industry through research and communication;
• To distribute pertinent information to the wheat industry; and
• To offer advice and support to the USDA-ARS Wheat Quality Laboratories.

An integral part of this program is a uniform grow-out program which enables samples to be grown in the same set of environments. The reports are present on the quality of new varieties approaching market stage, and all sectors of the industry have the opportunity to share their opinions. In the U.S., where there is no varietal registration system, this provides an important series of checks and balances for new varietal releases, and provides insight into future market needs.

In 1987 the Commission of the European Communities sponsored a symposium on the agronomic, technological, biochemical and genetic aspects of hard wheat at San Angelo Lodigiano, near Milan. The primary purpose was to address the over-production of lower quality soft wheat in the EC and the shortfall in higher quality hard wheat, a significant quantity of which had to be imported each year. It was believed that southern Europe could not compete with the higher yields obtained in northern Europe, but the shorter growing season and generally warm dry harvest was amenable to high quality hard wheat production which could provide a price premium. It was acknowledged that Europe was still struggling to come up with a market classification system and greater coordination was required. However, the large differences in market requirements for bread wheat among the member countries made it difficult to standardize.

In 1993 The Association of Applied Biologists sponsored "Cereal Quality III" in Cambridge, England. The symposium covered markets, quality, breeding, management and a range of topics affecting the cereal industry in general. It was broader in scope than our current meeting but represented an ongoing effort to bring diverse sectors of industry together.

In Australia, a Wheat Quality Objectives Group (WQOG) was formed and reported its findings at the Wheat Breeding Society of Australia meeting in Adelaide in 1994. The objectives of the group were as follows:

• To identify significant and emerging end products in the various markets;
• To identify the quality requirements of the major end products and their manufacturing processes;
• To translate these requirements into quality objectives for breeding programs;
• To identify gaps in their understanding of quality requirements; and
• To recommend areas for research into wheat quality.

The WQOG identified 21 end products ranging from pan breads to white salted noodles. For each product, the desirable wheat quality traits were listed and included as check varieties were those wheat varieties which most consistently met the criteria for each end-use product. Most importantly, the group was able to identify eight requirements that were common to all 21 end products, namely:

• There is limited demand for wheat below 10% protein content;
• There is a limited and specialized demand for soft wheat;
• The majority of products call for hard grain;
• All require high milling quality;
• All require high dough extensibility;
• There is no requirement for yellow pigment except in durum;
• There is no requirement for low paste viscosity starch; and
• Color stability in the flour is essential.

This provided some direct guidelines to those involved in varietal improvement and was designed to improve responsiveness to market needs. The Australian Wheat Board played a significant role in facilitating the group but it was an example of a forum where clear industry objectives were defined, with the goal of improving the competitiveness of Australian wheat in world wheat trade.

3. Current Trends in Quality Improvement

Wheat breeders have had to traditionally walk a tightrope between meeting the needs of growers and meeting the needs of industry. This has usually involved maintaining an acceptable level of quality while increasing yields and lowering production risks. However, opportunities for identity preserved wheat varieties are starting to change the picture, and more partnerships with millers and end-processors are being developed. In the U.S. SRW wheat area, certain millers have made a commitment milling certain wheat that meets their quality standards and are specifying varieties. Thus, quality may well be the price of admission into certain markets, and while our colleagues in Canada and Australia have addressed this issue for years, it is a relatively new phenomenon here in the U.S. In other cases, end-users will likely have to pay a premium for certain specific qualities. This is already appreciated in Europe; in Spain, wheat with an alveograph "W" value of over 400 commands a significant price premium over other wheat.

Breeders are also looking for new predictive tests that will enable them to replace 'wet chemistry' with NIR and ELISA. Because European wheat in general has a lower frequency of desirable HMW glutenin subunits, these analyses have been used for some years in screening lines for breadmaking potential. We are now using them more widely in our soft wheat program to screen for potential bread wheat varieties for eastern mills. Rapid tests for gliadins and LMW glutenin subunits could add value to the testing for protein quality. Considerable progress has been made with NIR within a market class, and good calibrations have been developed for several key traits.

I earlier referred to the importance of consistency of quality and the stability of varieties over changing environmental conditions. Work on protein solubility fractions are starting to provide some important clues in this area, and this now needs to be brought to a more rapid screening mode.

Marker-assisted selection is still in its infancy in identifying key quality traits, but progress is being made and probes have been developed for several genes with a major effect on protein and other quality parameters.

4. The Potential for New Food and Non-food Products

Wheat biotechnology research has made considerable strides in recent years and stable transformation has been achieved by a number of laboratories. The capacity to move novel HMW glutenins into wheat via transformation opens up some intriguing possibilities. At the CSIRO in Canberra, Australia work is underway on starch modification. These represent just two examples that could have future impact. Waxy wheat, with no amylose, has now been obtained in Japan and the U.S. and could lead to some niche market opportunities.

In the U.S. the most common non-food use of wheat is for grazing. This is widely practiced on about 300,000 ha of irrigated land in the Texas High Plains. About

75-90% of this wheat is managed for grazing and is planted as much as six weeks earlier than wheat planted solely for grain production. Fall growth can produce the equivalent of as much as 5 tons/ha of oven-dried forage.

In Europe wheat is the leading feed grain, followed by barley. Lack of adequate heat units for maize in northern Europe limit to use of this crop to silage production. To date, comparatively little effort has been devoted to addressing feed wheat quality. However, with concerns over phosphorus nutrition and environmental pollution, there is a need to lower the phytate content of wheat. This, coupled with improvements in total digestible nutrients (TDN) offers opportunities to improve the value of wheat as an animal feed.

5. Changes in Market Requirements Over the Next Ten Years

Automation in the baking industry has brought about some profound changes in raw material. Consistency and stability have become watchwords. Quality will always be the consequence of a genotype by environment interaction. A thorough knowledge of the genetic, chemical and molecular basis of dough quality is required if we are to formulate strategies for manipulating dough properties by traditional or molecular breeding.

Having said this, what changes might we expect in the next ten years in market requirements. Our ongoing dialog with millers, bakers and food companies provides some insights. Allow me to share a typical scenario with you: during our meeting with "Food Company X", we will discuss the quality traits that can be varied genetically, and also the range of variation that exists within our breeding programs. We will then ask if there are any profiles of particular interest to "Company X," so that we might deliver samples for them to evaluate. The response is that they would prefer to receive samples covering a range on end-use qualities, so that they might determine which product meets their specific end-use requirement. At issue is confidentiality on products and profiles in a highly competitive industry! However, we have been able to make progress in several countries.

Here are eight changes, or trends, that I believe will occur in the next ten years, and several are already underway:

1. There will be a trend towards more identity-preserved wheat, and end-users will request exclusive use on certain varieties:

We are seeing this occurring today, and it will lead to closer links between seed companies and end-users. A consequence of this could well be more vertical integration within the food industry. The largest brewer of beer in the U.S. already has its own barley breeding program, malts its own barley, and sends the malt direct to its own brewery. Growers produce under contract for the maltings plant. One cautionary note is that seed companies will have to take a careful look at how many units of seed per year would be sold if exclusivity is granted to an end-user.

2. Quality demands will become more stringent, and end-users may have to pay more for the qualities they desire:

In Spain quality wheat is defined largely on the basis of a physical dough test instrument result, namely an Alveograph "W" value of 400 or above. Wheat that qualifies in this category receives a price premium of about 25% over other milling wheat. In France quality is a component of the registration system, and the higher the quality score the lower the performance advantage needed over the check cultivars in order for the new line to be registered. However, although wheat could be registered in the "A" (or top) quality category with a yield below that of the checks, no such varieties are registered because the farmers are sufficiently compensated for growing the low-yielding/high-quality genotype.

3. Market segmentation will increase:

In France, Germany, and Austria there was no previous category for a biscuit wheat. These came under the feed wheat category with zero premium. This has been changed to ensure that end-users have a choice. In the U.S. Soft Red Winter wheat is used for a diversity of end-users ranging from cake flour to crackers, cookies, pie crusts, breadings, etc. However, soft wheat quality has to this date been defined on the basis of some standard tests such as break flour yield, particle size index, alkaline water retention capacity, and cookie spread and diameter. While these tests have value, they do not describe quality for the range of products made. The first piece of work that the U.S. Wheat Quality Council is examining is to segment the soft wheat market into three or four broad categories with the most appropriate tests for each category. This, in turn, will lead to varieties being diverted into more specific market segments.

4. Local end-users and overseas customers will have a greater role in defining quality:

In the U.K. the National Association of British and Irish Millers receive samples of wheat being grown in the second year of registration by the National Institute for Agricultural Botany (NIAB). They develop a "millers consensus" on the quality of the new wheat, and this report has a major impact on varieties entering the recommended list trials following registration. This is a separate report from the official Flour Millers and Bakers Research Organization (formerly Chorleywood). In the U.S. there is no official registration system for wheat. However, the opinions provided by the participating millers and bakers at the Wheat Quality Council meetings have a significant effect on release decisions. We are also seeing an increasing trend in having overseas buyers adopt a more proactive approach in defining their quality needs and asking that breeders develop the required products. These requests were formerly conveyed via official export channels, but the dialog between breeding company and overseas buyer will likely increase.

5. Stability of quality will assume increased importance and a database on performance will likely become a necessity:

As mentioned above, modern processing technology requires a more consistent product. Many of the baking tests are still run on composite samples derived from multiple locations. To date, we have not defined what constitutes an acceptable level of variation across environments and years. We are beginning to understand the chemical basis of such variation. In future, such stability parameters as deviations from the regression of varietal performance across an array of environments for a specific quality trait may well complement more precise measurements such as gliadin/glutenin ratios. One thing is clear, while opinions on what constitutes stability of quality will differ, those institutions that thoughtfully compile a database will go further towards meeting customer needs.

6. Advances in biotechnology research will improve our capacity to modify protein constituents, and this could lead to new products:

To date, we have cases in which the removal of existing HMW glutenin subunits has lead to the development of lines with "super-extensible" dough. Experiments with bacterial protein inserted into wheat via transformation could enhance existing products, or lead to totally new products. New markets may well have to be created for such products.

7. An objective end-use system of wheat classification will be used as the principal marketing tool:

The U.S. Federal Grain Inspection Service is currently engaged in changing the criteria for wheat classification based upon objective measurements rather than such items as kernel shape which were used in the past. The single kernel hardness tester will be used to differentiate hard from soft wheat. Advances in Near Infra Red (NIR) technology are beginning to provide rapid methods for the objective measurement of end-use quality. These changes were precipitated by breeders making increasingly diverse crosses that rendered classification on the basis of kernel morphology impossible. Western Canada still uses kernel morphology as the principal means of classifying Canada Western Red wheat and that of other market classes. This is why breeders in western Canada continue to cross the same material and use backcross breeding to keep their lines resistant to diseases.

8. More markets will open up for non-food uses of wheat:

In the U.S. and Canada average wheat yields are only one-third that of maize. In France and Germany, wheat yields match that of maize, while in the U.K. wheat predominates, and what little maize is grown is used for silage. In Denmark 96% of the wheat crop is used as a feed grain and the country finds it more economical to import their milling wheat from other EC countries. Low or zero phytate wheat could have a major impact in improving phosphorus nutrition. Grazing of winter wheat is practiced on 300,000 hectares in the Texas High Plaines. In recent years there has been an increase in the use of whole-crop wheat as an animal feed in the U.K. Finally, low amylose wheat has been discovered, and the opportunity for modified starches could open up new market opportunities. Plant breeding companies and institutions are looking for ways to leverage their existing germplasm resources through the identification of new markets for identity-preserved wheat. A change in mindset is needed to look beyond the conventional quality tests and identify sources of variation among basis constituents of starches, proteins, lipids, vitamins, fiber, and minerals.

Identifying new uses for wheat is a multi-disciplinary team effort. New sources of variability are being identified within the wild species, and the introgression of genes, chromosome segments and whole chromosomes into common wheat has had a significant impact. However, wheat is fundamentally a food crop, and meeting the changing needs of our domestic and overseas markets remains the primary challenge.

Conclusion

This has been a brief attempt at looking at quality on a global basis. It now remains for our special sessions to delve into the various aspects of wheat quality. The delivery of quality is a team effort and this is especially true in our industry. As I stated at the outset, I have likely brought too much breeder perspective into this review. However, I am confident that the organizing committee has ensured that there will be an overall balance. There is an ongoing need for greater communication and understanding among the different sectors of our industry, and I am confident that this objective will be attained.

References

Aitken, T.R. and J. Ansel Anderson. 1947. Conflicting Opinions on the Quality of Bread Wheats. Proc. Amer. Assoc. Of Cereal Chemists 5 (1) : 6-18.

Cholick, F. 1989. Personal communication.

Cox, T.S., M.D. Shogren, R.G. Sears, T.J. Martin and L.C. Bolte. 1989. Genetic Improvement in Milling and Baking Quality of Hard Red Winter Wheat Cultivars, 1919 to 1988. Crop Sci. 29: 626-631.

 * - From Proceedings of the IWQC, 1997