American demand for low fat, low cholesterol, high soluble fiber food stuffs increased in the 1980s. Oat based cereals increased in the marketplace. Soluble fiber of both oats and barley are due the polysaccharide walls of these grains.Barley was deemed to be possible choice for cereals like oats. growing conditions and the genotype affect the B-glucan levels in both oats and barley.In studies discussed here, the effect of plump kernels, hull-less kernels, alkaline viscosity, grain protein content, and total and soluble B-glucan content were factors used in studies covered in this article. This study was paid for by barley by the North Dakota Barley Council

Faue, A.C.

Horsley, R.D.

Manthey, F.A.

Schwarz, Paul B.

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Survey of lJ.glucan Content of Barley Cu tivars Adapted to 'North Dakota R.D. Horsley Assistant Professor Department of Crop and Weed Sciences P.B. Schwarz Assistant Professor Department of Cereal Science and Food Technology A.C. Faue Former Graduate Research Assistant Department of Crop and Weed Science FA. Manthey Research fusociate Department of Cereal Science and Food Technology Elevated serum cholesterol levels are widely recognized as a significant risk factor for the development of hean dis­ease. In the past decade, dietary modifi­cations which may reduce serum choles­terollevels have become a major concern of a large portion of the American pop­ulation. These modifications include reduction of roral fa t and increasing the intake of soluble dietary fiber. Soluble fiber from oat (Avena sativa 1.) and oat bran have been associated with a hypo­cholesterolemic effect (Anderson et al., 1984). A:, a consequence, the number of oat­based cereals and food products available in the marketplace has increased dramati­cally. Barley also is an excellent source of soluble fi ber and has been associated with cholesterol-lowering effects in humans Newman et al. , 1989). These facts have stimulated increased interest in barley both as an economical source of dietary fiber and as a healthy food ingredient. The soluble fiber of barley and oats is composed primarily of polysaccharides from the cell walls of the grain. The major soluble components of barley and oat fiber are j-glucans.j-glucans recently have been identified as the consti ment responsible for the hypocholesterolemic effect of oat bran (Davidson et al., 1991). j-glucan content of oat and barley is affected by both genotype and growing conditions, but genetic factors appear to be of greater significance (Stuart et al., 1988; Welch er al., 1991 ). Totalj-glucan content of oat cui tivars has been reported to range from 3.9 to 6.8 percent in the groat (Wood et a1., 1991). Approximately 80 percent of the j-glucans in oats are soluble (Arnan and Graham, 1987). Totalj-glucan content of hulled malting and feed barley cultivars has ranged from 2 to 10 percent (Bamforth, 1982). On average, 54 percent of barley j-glucans are soluble. Culrivars expressing hull-less or waxy endosperm traits are, in general, greater inj?glucan coment (Fox, 1981). Hull-less barley cultivars as high as 16 percent in j?glucan have been reported (Newman et aI., 1989). The cuIcivar Wanubet, a waxy huIl­less barley, has been grown under contract on a limited acreage in Nonh Dakota since 1989 for sale to food pro­cessors. Wanubet yields approximately 30 percent less than hulled cultivars grown in North Dakota because of its weaker straw, susceptibility to disease, and lower genetic yield potential. The majority of hulled cultivars currently grown in North Dakota were developed for malting and brewing use and are inheren dy low in j?glucan content. High levels ofj-glucan content in malt can cause filtration and haze problems in the brewing process Bamforth, 1985; McCleary and Gennie­Holmes, 1985) . High yielding cultivars with high j?glucan content are necessary to satisfy barley producers and the food processing industry. The barley breeding program at the North Dakota Agricultural Experiment Station has been developing waxy hull­less barley cultjvars adapted to North Dakota. A:, part of the breeding program, a survey was conducted to determine the total and soluble j?glucan content, alkaline viscosity, grain protein, and 24 percent plump kernels of elite hulled and hull-less barley lines adapted to North Dakota. Nine barley genotypes representing hulled and hull-less and waxy and non­waxy endosperm were evaluated in this study (T able 1). Entries were grown at ...Carrington, M inot, and Langdon in 1988 and 1990 and at Carrington, Langdon , and Prosper in 1989. Entries were grown under flood irrigation at Carrington. Mean [Otal j?glucan of the nine genotypes was 4.54 percent and ranged from 4.27 to 5.52 percent (T able 2). This range is less than the 2 to 10 percent range reported by Bamforth (I 982) yet similar to results reported by other researchers (Aman and Graham, 1987; Henry, 1985). The lower [0 tal j?glucan content of genotypes evaluated in this study may be due to the fact that they were developed in 'mahing" barley breeding programs in which high levels ofj?glucan in the malt are undesirable. Waxy Bowman had significantly greater [otal j?glucan and alkaline viscosity than all genotypes and signifi­cantly greater soluble j?glucan content than all genotypes except Azure (Table 2). Ullrich er al. (1986) also found that waxy genotypes had greater [Otal j?glucan content and alkaline viscosity than nor­mal genotypes. Bowman had the lowest total j?glucan content of all genotypes and no significant difference was observ­ed between Bowman and genotypes with the lowest soluble j?glucan content and alkaline viscosity. Mean soluble j?glucan content as a percent of [ocal (SIn across genotypes was 55.9 percent (Table 2). Azure had the greatest SIT , 62.6 percent, and Excel the lowest, 52.6 percent. Aman and Graham (1987) observed a greater mean SIT, 55.8 percent, and range, 38 to 69 percent, for barley genotypes adapted ro Montana and Sweden. H ull-less Bowman and Waxy Bow­man are near-isogeneic lines of Bowman. They are genetically similar to Bowman except for a one gene difference. Hull-less Bowman differs fro m Bowman by the presence of the n gene conferring the hull-less character. Waxy Bowman differs from Bowman by the presence of the wx gene conferring the waxy endosperm character. The wx and n genes were responsible, in part, for increasing total and soluble ­glucan content and alkaline viscosity of Waxy and Hull-less Bowman over that found in Bowman. The wx gene had the greatest effect, increasing total and soluble j?glucan content 1.25 and 0.68 percentage units, respectively, and alka­line viscosity 1.7 Cs above that of Bow­man (Table 2). Total j?glucan content of Hull-less Bowman was significantly greater than rhar of Bowman. Soluble j?glucan content of these two genotypes did not differ significantly; however, soluble j?glucan content of Hull-less Bowman tended ro be greater than that of Bowman. Ullrich et al. (1 986), in a study com­paring total j?glucan content of normal barley and their waxy near-isogeneic pair in several genetic backgrounds, also observed rhat the wx gene caused an in­crease in total JT-glucan content. The increase ranged from 0.4 to 3.5 percent­age units and averaged 1.6 percentage units. The difference they observed in rotal j?glucan content between normal and waxy endosperm near-isogeneic pairs was affected not only by the wxgene but by the genetic background of the pairs and the environment in which they were grown. Hot:, dry growing conditions during grain fill tend to increase total j?glucan content (Hockett et al., 1987; Ullrich et al., 1986), Table 2. Mean total and soluble B-glucan, alka line viscosity, plump kernels, and grain protein of nine barley genotypes grown over eight environments in North Dakota, 1988-1990. Soluble Total Soluble 8-glucan as Alkaline GrainTable 1. Phenotype and origin of barley genotypes Genotype 8-glucan 8-glucan % of total viscosity proteinevaluated. % CSl %% Genotype Hull type Endosperm Origin Azure 4.86 d2 3.04 be 62.6 e 2.94 cd 13.8 abc Azure Hulled Non-waxy NDAESl Hazen 4.51 b 2.43 a 53.9 ab 2.46 ab 14.0 be Hazen Hulled Non-waxy NDAES Bowman 4.27 a 2.45 a 57.4 b 2.52 ab 14.1 be Bowman2 Hulled Non-waxy NDAES Excel 4.73 cd 2.49 a 52.6 a 2.51 ab 13.2 a Excel Hulled Non-waxy MAES3 Robust 4.65 be 2.46 a 52.9 a 2.29 a 14.3 c Robust Hulled Non-waxy MAES B1602 4.49b 2.41 a 53.7 ab 2.62 abc 13.6 ab B1602 Hulled Non-waxy BAR I4 B1603 4.46 ab 2.48 a 55.6 ab 2.71 be 14.2 e B1603 Hulled Non-waxy BARI Hul Bowa 4.74 cd 2.75 ab 58.0 be 3.47d 15.7 d Hulless-Bowman2 HUll-less Non-waxy NDAESs Wax Bow4 5.52 e 3.13 e 56.7 ab 4.21 e 15.5 d Waxy Bowman2 Hulled Waxy NDAESs Mean 4.54 2.54 55.9 2.63 14.4 lNDAES = North Dakota Agricultural Experiment Station 'CS =Centistokes 2Two-rowed barley 2Means followed by the same letter are not significantly different at the (p<O.05) 3MAES = Minnesota Agricultural Experiment Station probabili ty level. 4BARI = Busch Agricultural Research, Inc. 3Hul Bow =Hull·less Bowman 5Unreleased germplasm from the NDAES 4Wax Bow ;;;;; Waxy Bowman 25 The effect of genetic background on jS-glucan content indicates that when breeding for new cultivars with high jS-glucan content, the choice of parents is important. The inherently greater total and soluble -glucan content and SIT value of Azure as compared to other culti­va~ currently grown in North Dakota (Table 2) suggests that Azure may be a good parent. The development of a hull­less waxy Azure genotype bred by back­crossing the wx and n genes into an Azure genetic background might produce a cul­tivar with high total and soluble jS-glucan content and excellent agronomic perfor­mance. A bottleneck in any breeding pro­gram is evaluation of experimental lines for speCific traits. In breeding for high soluble jS-glucan barley cultivars. evalua­tion ofj-glucan content will be rime con­suming and expensive. Identification of a trait that is highly correlated to soluble j?glucan content and inexpensive to measure could increase the efficiency of a breeding program because the correlated trait could be used to identify lines with high soluble jS-glucan content. The use of grain protein content, alkaline vis­cosity, and kernel plumpness to estimate j?giucan content have been investigated by several researchers. In two studies by Henry (1985, 1986), a positive relationship was observ­ed between totaljS-glucan conrent and grain protein content. However, the relationship between the twO traits was not strong enough to successfully select for high jS-glucan lines by selecting for high protein lines. Ullrich et al. (1986) and Hockett et al. (1987) evaluated the relationship between alkaline viscosity and total/-giucan content. In both studies, a positive relationship significant­ly different from zero was observed. Ullrich er al. (1986) found a correlation of r=0.55 (P<O.Ol, n=21) between the two characters. They concluded this rela­tionship was not strong enough to allow successful selection of high j-glucan lines based on alkaline viscosity. Hockett et al . (1987) found a much stronger relation­ship (r=0.87, P<O.Ol, n=192). They stated that alkaline viscosity could be used to estimate jS-glucan content. The relationships between total and soluble jS-glucan content, alkaline vis­cosity, grain protein content, and kernel plumpness were estimated by calculating simple correlations (Table 3). Correla­tions significantly different from zero were found for total vs. soluble-glucan content (r=0.71, P<0.05 , n=75), alkaline viscosity vs. soluble -glucan content (r=0.42, P<0.05, n=75), and plump kernels vs. totaljS-giucan contenr (r=0.38, P<0.05, n=75). Even though the cor­relation values were significantly different from zero, the relationships were not strong enough to allow prediction of jS-glucan levels using these traits. Acknowledgement This study was funded in part by the North Dakota Barley Council. T he authors wish to express their gratitude to Dr. J.D. Franckowiak (NDSU, Fargo, ND) for providing seed of Waxy and Hull-less Bowman. Literature Cited Arnan, P. and H. G raham. 1987. Analysis of tOtal and insoluble mixed-linked (1-3), (l-4)-jtglucans in barley and oats.]. lnst. Food Chern. 35:706-709. Anderson , J.W.• L. StOry, B. Sieling, W .L. Chen, M.S. Petro, and]. StOry. 1984. Hypocholesterolemic effects of oat bran or bean intake for hyupocholesterolemic men. Am. J. Clin. Nucr. 40:1146-1155. ASBC. 1976. Methods of analysis of the American Society of Brewing Chemists. ASBC, St. Paul, MN. Barnforth, C.W. 1985. Biochemical ap­proached ro beer quality.]. inS{. Brew. 91:154-160. Bamfonh, C.W. 1982. Barley f?glucans: their role in malting and brewing. Brew. Dig. 22:27. Davidson, M.H., L.D. Dugan, ].H. Burns, J. Bova, K. Story, and B. Drennan. 1991. The hypocholesreroJemic effecrs ofJ? gJucan in oatmeal and oat bran. JAMA 265:1833-1839. Fox, G.]. 1981. The effect of (he waxy endosperm, shorr awn, and bulless seed genes upon biochemical and physiological seed characteristics important in barley (Hordeum vulgau L.) utilization. Ph.D. Thesis, Absrract no. DE 082-14646, Montana State Univ., Bozeman, MT. Henry, R]. 1986. Genetic and environmental variation in the penrosan and j?glucan contents of barley, and their relation to malting quality. ]. Cereal Sci. 4:269-277. Henry, R.]. 1985. A comparative study of the roral j?glucan contents of some Australian barleys. Aust.]. Exp. Agric. 25:424-427. Hocken, E.A., c.P. McGuire, c.w. Newman, and N. Prentice. 1987. The relationship of barley J?glucan content co agronomic and quality characteristics. pp. 851 -860. .In S. Yasuda and T. Konishi (cds.) Badey Generics Y. Proc. 5th Int. Barley Genet. Symp., Okayama, Japan, 6­11 October, 1986. McCleary, B.Y. and M. Gennie-Holmes. 1985. Enzymatic quantification of 0 -3), (l-4)-hlucan in barley and malt. J. Insr. Brew. 91:285-295. Newman, R.K., C.W. Newman, and H. Grahm. 1989. The hypocholestetolemic function of barley J?glucans. Cereal Foods World 34:883-886. Continued on page 34 Table 3. Correlation coefficients between total and soluble IJ-glucan content, grain protein, alkaline viscosity, and plump kernels of barley grown In North Dakota, 1988 to 1990 (n=75). Total IJ.glucan Soluble IJ.glucan Alkaline viscosity Plump kernels Grain protein .34 .07 .24 .10 Total 8-glucan .71" .28 .38' Soluble 8-glucan .42' .26 Alkaline viscosity .12 ',"Significantly different from zero at (p<O.05) and (P<O.01) probability levels, respectively. 26 

Survey of B-glucan Content on Barley Cultivars Adapted to North Dakota

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