| | Food barley development at the Crop Development Centre (CDC), University of Saskatchewan grew out of the longstanding hulless barley development program at the CDC. The food barley sub-project was initially based on crosses made in the mid-1970’s with the 95% amylopectin starch genotype “waxy Betzes” from Montana State University. These crosses, aimed at producing hulless waxy barley, had been made with the original intent to produce barley varieties that could be used to provide waxy starch for use in the solution mining system employed in several Saskatchewan potash mines. While this utility has not come to pass to date, the material provided an excellent base from which our food barley R&D efforts have developed.
Because of our joint program efforts on oat R&D, our resultant interaction with the oat food industry, their keen interest in beta glucan and soluble dietary fibre in the 1980’s and our knowledge of the tremendous variability in beta glucan content in barley germplasm, especially in the waxy starch type, we were able to foresee a possible increased opportunity for barley in the food industry and embarked upon specific food hulless barley development. Thanks to support from the Saskatchewan Agriculture Development Fund and the Alberta Wheat Pool, Agricore and now Agricore United we have been able to make good progress.
Selection for the waxy type has and is still conducted first by visual inspection of lines from crosses between waxy starch and normal parents to select the waxy segregates. In hulless material this is actually quite easy as the waxy segregates have a much lighter grain colour and, if in doubt, one can cut through the kernel to see if the endosperm is floury. Initial chemical selection was based largely on analysis of acid extract viscosity (AEV) as we did not have affordable access to equipment to analyze large numbers of samples for beta glucan (BG). The strong positive correlation between AEV and BG in waxy starch material allowed reasonable success with this crude screening technique.
However, it is desirable to screen for both BG and AEV in order to develop a diverse selection of high BG varieties with variable AEV for different end-users. Therefore, more recently the CDC program annually screens a significant number of samples for both BG concentration and AEV. BG is determined by Flow Injection Analysis (Aastrup, S. and Jorgensen, K.G., 1988) using a Fiatron Flow Injection analyzer, Oconomowoc, WI and AEV (Greenberg, D.C. and Whitmore, E.T. 1974) is determined using a Brookfield Digital Viscometer Model DV-II. We strongly believe our combined selection for high BG and high AEV is a major reason for the repeated desirability of our materials in various evaluations for food and industrial purposes.
While initially working mainly with the 95% amylopectin waxy starch types the program works on 100% amylopectin starch types (pioneered at the CDC), has an effort dedicated to improvement of high amylose (approx 40%) hulless types and has hulless compound granule or fractured starch types under evaluation and development.
As indicated earlier, the 95% amylopectin waxy type is based on using “waxy Betzes” as the original donor parent. Success to date in the program has been demonstrated by the release of CDC Candle (1995) and CDC Rattan (2003). CDC Candle normally demonstrates BG concentration of 6.5% – 7.0 % and has relatively high AEV. CDC Rattan shows a 0.8 % improvement in BG with similar moderately high AEV (Table 1), and is much improved agronomically being higher yielding, stronger strawed and demonstrating improved threshability at harvest (Table 2).
Table 1. % Beta Glucan and Acid Extract Viscosity (cps) for five CDC varieties and four CDC selections of hulless specialty starch barley at Saskatoon 2000 through 2004.
 | %BG | AEV |
| Genotype | 2000 | 2001 | 2002 | 2003 | 2004 | 2000 | 2001 | 2002 | 2003 | 2004 |
| CDC McGwire | 5.5 | 5.3 | 4.8 | 5.1 | 3.9 | 11 | 18 | 6 | 20 | 4 |
| CDC Candle* | 6.2 | 6.7 | 6.5 | 7.0 | 6.0 | 51 | 93 | 12 | 207 | 13 |
| CDC Rattan* | ----- | 7.8 | 7.3 | 7.7 | 6.3 | ----- | 235 | 30 | 239 | 18 |
| CDC Alamo** | 7.0 | 7.9 | 7.9 | 8.0 | 6.3 | 41 | 207 | 52 | 93 | 19 |
| CDC Fibar** | 11.8 | 9.6 | 10.0 | 10.1 | 9.1 | 204 | 347 | 63 | 514 | 56 |
| SR93139* | 8.5 | 9.3 | 8.5 | 9.2 | 7.1 | 434 | >1000 | 81 | 578 | 71 |
| SB94893^ | 8.5 | 8.4 | 8.2 | 9.6 | 7.6 | 46 | 58 | 22 | 220 | 11 |
| SH99250^ | ----- | 6.8 | 7.9 | 8.7 | 7.3 | ----- | 22 | 14 | 34 | 7 |
| SH99073^ | ----- | 7.7 | 8.0 | 9.2 | 7.0 | ----- | 55 | 8 | 94 | 7 |
* 95% amylopectin starch
** 100% amylopectin starch
^ high amylose starch
Note: lower BG and especially AEV levels in 2002 and 2004 indicate adverse (wet) pre-harvest conditions.
Table 2. Agronomic, BG and AEV data 2001 and 2002 PRRCG, Western Canadian Hulless Barley Cooperative test.
| Yield
% McGwire | Lodging (1-9) | Dirty Test Wt. (kg/hl) | Clean Test Wt. (kg/hl) | % Plump Grain | %
BG | AEV (cps) |
| CDC McGwire | 100 | 3.4 | 74.1 | 78.6 | 76 | 4.7 | 16 |
| CDC Candle | 86 | 5.5 | 70.2 | 76.6 | 61 | 6.4 | 121 |
| CDC Rattan | 95 | 3.0 | 71.3 | 78.1 | 80 | 6.9 | 150 |
| # Station Years | 25 | 6 | 21 | 27 | 20 | 2 | 2 |
Crossing the CDC two row hulless waxy breeding line SB85750 and the six row hulless waxy variety AzHul from the University of Arizona in 1990 to determine if the gene(s) giving rise to the waxy starch in these different germplasm sources was the same gave two interesting results. First was the indication that the genes controlling the waxy starch trait were different based on the fact the some segregates from the cross had normal starch type. More interesting and valuable was the result that some unique segregates had 100% amylopectin starch, a first in barley development (Bhatty and Rossnagel, 1997), and we believe a first in that 100% amylopectin barley starch is the only available native form of pure amylopectin starch.
Of considerable note with this unique waxy type was even higher levels of BG and AEV as demonstrated by the varieties CDC Alamo (released in 1999) and CDC Fibar (released in 2003) (Table 1). CDC Alamo normally has a BG concentration of near 8% with high AEV, while CDC Fibar consistently produces BG concentration > 9% and has on several instance had BG > 10%. While CDC Fibar has considerably higher BG and AEV, it does not offer any improvement in agronomic performance (Table 3).
Table 3. Agronomic, BG and AEV data 2002 PRRCG, Western Canadian Hulless Barley Cooperative test.
| Yield % McGwire | Lodging (1-9) | Dirty Test Wt. (kg/hl) | Clean Test Wt. (kg/hl) | % Plump Grain | % BG | AEV (cps) |
| CDC McGwire | 100 | 2.4 | 74.2 | 77.8 | 75 | 4.7 | 5 |
| CDC Candle | 86 | 4.9 | 70.5 | 76.0 | 72 | 6.5 | 16 |
| CDC Rattan | 98 | 1.9 | 71.4 | 77.3 | 81 | 7.1 | 18 |
| CDC Fibar | 78 | 2.9 | 66.0 | 73.5 | 88 | 9.1 | 52 |
| # Station Years | 14 | 3 | 9 | 11 | 10 | 6 | 6 |
Within the 95% amylopectin waxy type, CDC selection SR93139 is of note in that it has BG levels approaching that of CDC Fibar and has exceptionally high AEV (Table 1). These traits may be an advantage in non-food industrial applications.
CDC high amylose hulless materials are represented specifically by SB94893 a two row selection which derives its high amylose starch from the hulled genotype high amylose Glacier. As is the case for high amylose Glacier, SB94893 has starch which is about 40% amylose and it has high BG with moderately high AEV (Table 1). Food industry interest in high amylose types is increasing as interest in “resistant starch” increases, since, relative to amylopectin, amylose behaves like resistant starch. Unfortunately, our experience has been that developing agronomically acceptable high amylose material from the high amylose Glacier background is a definite challenge. While selections like SB94893 are certainly “growable” under normal field conditions, these materials tend to be very tall, weak and relatively low yielding and we have put much less effort into improving these types to date. With increased interest in resistant starch we have recently increased efforts on this type.
Of note are CDC selections SH99250 (2 row) and SH99073 (6 row), both of which, while having no evidence of differential starch type in their pedigrees, have been found to be high in amylose and have elevated BG and somewhat elevated AEV levels (Table 1). As part of our ongoing hulless food barley effort and our annual routine screening of 1000’s of selections for BG and AEV we have always been on the lookout for normal starch lines with elevated BG and/or AEV since some potential users have indicated a desire for > BG, but that the waxy or high amylose starch was undesirable for their end-use(s). Based solely on high BG concentration, SH99250 and SH99073 were retained, advanced and increased for just that purpose.
However, since the pedigrees of these two lines gave no evidence either should have altered starch type, they were not evaluated for amylose/amylopectin ratio until relatively recently and, much to our surprise, both selections have elevated amylose levels. While not quite as high in amylose as the 40% amylose derivatives from high amylose Glacier, these selections are definitely not normal 25% amylose starch type, as they consistently demonstrate amylose levels > 35%. Of special interest is that both of these selections have relatively good agronomic performance and are much better field performers than high amylose Glacier derivatives. These selections are currently being further evaluated and crosses have been between them and with high amylose derivatives like SB94893 to determine if the high amylose in these unique selections is under different genetic control. There is of course an outside chance that combining these materials may also result in selections with amylose >40%.
While not yet widely used in the food or non-food industries, considerable success has been generated using our 95% and 100% amylopectin hulless waxy material at the research and indeed even at the commercial level. In particular, research level efforts by N. Ames at the CRC, AAFC, Winnipeg; T. Vasanthan and F. Temelli, University of Alberta; M. Izydorczyk and J. Dexter, GRL, CGC, Winnipeg and M. Izydorczyk, J. Li and R. McCaig, CMBTC, Winnipeg have demonstrated unique value for uses in tortillas, high soluble fibre snacks, BG extraction and concentration, noodles and bread products. At the commercial level, InfraReady Products Ltd., Saskatoon has developed a unique, biodegradable, environmentally friendly cat litter, LitterMateTM which is being marketed across western Canada, Cevena Bioproducts, Edmonton has been using these high BG hulless barley materials as the basic feedstock for their BG concentration and extraction process, Sapporo Breweries, Japan have expressed considerable interest in the use of our 100% amylopectin materials CDC Alamo and CDC Fibar for a new food barley venture in Japan, and the Saskatchewan potash industry has again expressed interest in the possible use of these materials in their solution mining process.
In summary we see a good future for specialty starch hulless barley especially with elevated BG (thus soluble fibre) levels, and are confident that our project will serve as a good base for these purposes from a western Canadian plant breeding and barley R&D perspective.
References
Aastrup, S. and Jorgensen, K.G. 1988. Application of the calcofluor flow injection analysis method for determination of beta-glucan in barley, malt, wort and beer. J. Am. Soc. Brew. Chem. 46(3):76-81.
Bhatty, R.S. and Rossnagel, B.G. 1997. Zero amylose lines of hull-less barley. Cereal Chem. 74(2):190-191.
Greenberg, D.C. and Whitmore, E.T. 1974. A rapid method for estimating the viscosity of barley extracts. J. Inst. Brew. 90:178-180.
Special acknowledgements
Dr. R. S. Bhatty, Professor Emeritus (CDC), University of Saskatchewan.
Dick Klaffke, Alberta Wheat Pool and Agricore (retired).
Funding acknowledgements
University of Saskatchewan
Saskatchewan Agriculture and Food
Saskatchewan Agriculture Development Fund
Alberta Wheat Pool
Agricore Ltd.
Agricore United
B.G.Rossnagel, T. Zatorski and G. Arganosa
Crop Development Centre/Plant Sciences Department, University of Saskatchewan, 51 Campus Drive, Saskatoon SK S7N 5A8
Presented at the 18th North American Barley Researchers Workshop, July 17-20, 2005 |
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