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Arabinoxylan is an important hemicellulose potentially affecting wheat baking qualities, barley malt quality, and may impart prebiotic benefits. Water-extractable (WEAX) and total arabinoxylan (TOAX) were characterized in 204 wheat and barley accessions, respectively, using an orcinol-ferric chloride assay. WEAX measurement accuracy was optimum when glucose concentration was greater than 12–13 times pentose concentration. The modified method removed enough excess glucose spectral absorbance to make the corrected and uncorrected lines different, but still significantly correlated (p = 0.009, R = 0.94). Mean WEAX (expressed as percentage WEAX of TOAX) for the wheat accessions was 15.90%, ranging from 8.82% to 24.87%, and for barley accessions WEAX the mean was 7.10%, and ranged from 2.98% to 13.86%. Conclusions are 1) the assay is useful for a breeding program because of its semi-high throughput design for the simultaneous analysis of 16 (WEAX) to 40 (TOAX) barley lines or 24 (WEAX) to 40 (TOAX) wheat lines, 2) the trichromatic measurement reduces the impact of glucose, and 3) the broad range of WEAX measured showed that barley and wheat accessions vary in their extractable and unextractable components.

The chemical induced barley mutant m351 was first selected for its low level of mixed-linkage (1–3,1–4) beta-D-glucan (MLG) in an experimental effort to search for barley lines with varied grain MLG contents. The MLG decrease in m351 was associated with increased levels of fructans and crude fiber, but maintained the same plant characteristics under field conditions. The mutation was mapped to a genetic locus flanked by two SSR markers, Bmag369 and Bmag564, on chromosome 7H. Molecular cloning of the CslF6 gene from the m351 line revealed the presence of a point mutation, causing a substitution of an alanine for threonine at position 849 in the amino acid sequence of the corresponding protein. The resultant protein retains some functionality and affects other components in the m351 grain. Those metabolic changes associated with MLG reduction in m351 is the first case reported of a partially functional CslF6 gene in cereal grains. The results contribute to better understanding of the functional effects of the CslF6 gene and the mutant has potential implications in grain end-use quality improvement.

Rapid and economical measurement of amylose content in barley is important for genetic study and breeding improvement of this trait. Seventeen genotypes with a wide range of amylose contents were used to compare the amylose measurement accuracy of the cost-effective iodine–potassium iodide (I:KI) method to the commercially available enzyme-based Megazyme protocol. Comparable accuracy from I:KI was demonstrated in low amylose samples (below 10% dried base), as were limitations in regular or high amylose samples. To address the major cost of sample preparation in nutritional trait analysis, the I:KI method was also employed for amylose detection from β-glucan and free phosphate assay samples. Results indicated that samples used in β-glucan and phosphate assays could be further utilized for amylose measurement. Amylose detection accuracy using I:KI method from those assayed samples is comparable to that using the Megazyme method in low and regular amylose samples. Development of protocols for the double assays from one grain sample will significantly reduce the labor cost associated with sample preparation and will streamline the screening of early generation barley populations, where seed sample amounts are limited.