2001 AACC Annual Meeting Charlotte, North Carolina October 14-18, 2001 Charlotte Convention Center

The presence of the waxy gene in barley, as in other grains, produces a starch that is predominately amylopectin. In barley, the gene is also associated with an increase in beta-glucan (BG) and extract viscosity. The current study was undertaken to compare BG structure in waxy and non-waxy barley. A series of waxy and non-waxy isotypes of Compana barley, were grown in three locations, MT (1 site, in 1990) and AZ (2 sites, in 1991 and 1992). The two starch types were represented in hulled and hulless barleys with long and short awns (n=24). The barley was analyzed for protein, fat, fiber, BG and viscosity by approved methods. The distribution of beta-(1,3)-linked cellotriosyl and cellotetraosyl units, and of more cellulose-like structural sequences, were determined by High Performance Anion Exchange Chromatography of lichenase digests. Data were analyzed by SAS least squares procedures. Results confirmed previous findings of elevated BG levels and increased extract viscosity in waxy barley. The waxy barleys showed more of the beta-(1,3)-linked cellotriosyl than cellotetraosyl feature as determined from the molar ratio of lichenase released tri- and tetrasaccharide (T-T ratio; P < 0.002). T-T ratios in hulled vs hulless, long- vs short-awn and waxy vs non-waxy types and three locations were: 2.87, 2.89; 2.87, 2.90; 3.05, 2.74; and 2.88, 2.88, 2.89, respectively.