Production of Dryland Barley for Human Food: Quality and Agronomic Performance

Abstract

Grain β‐glucan content is the most important attribute for barley (Hordeum vulgare L.) varieties destined for the human food market. This trait is important because of the blood glucose and cholesterol‐reducing properties of β‐glucans. High levels of grain protein content, test weight, and seed size and endosperm color may also add value. Seed yield potential, in part, determines the economic feasibility of producing human food varieties. To determine the potential of food barley production in the dryland production areas of the Pacific Northwest of the United States, 33 cultivars and advanced lines reported to vary in β‐glucan content were grown in 2006 and 2007 at two locations in northeastern Oregon under dryland cropping conditions. Seed yield, test weight, percentage of plump kernels, grain β‐glucan, and grain protein were measured on replicated samples from the four environments, allowing for assessment of average performance as well as genotype × environment interaction. Estimates of variance components showed that ∼66% of the variability in β‐glucan content was attributable to genotype. Cultivars and lines with waxy starch had an average β‐glucan value of 55 g kg−1 compared with 35 g kg−1 for cultivars and lines with nonwaxy starch. We found significant two‐ and three‐way interactions, but these accounted for much less of the total variation in the measured phenotypes than the main effects of variety, year, and location. Hulless accessions produced an average of 3580 kg grain ha−1 compared with 4260 kg grain ha−1 for the hulled accessions. Hulled, waxy‐starch varieties appear to have the greatest agronomic potential for dryland production, as they combine high yield potential and grain β‐glucan percentage.

Barley Grain as a Source of Health-Beneficial Substances

“…Ehrenbergerová et al (2008) described β-glucan content in various barley lines in the range of 4.03-7.57%, Gamlath et al (2008) reported 1.8-6.1% andIzydorczyk andDexter (2008) 3.6-9.7%. Rey et al (2009) reported average β-glucan value of 55 g/kg compared to 35 g/kg for cultivars and lines with nonwaxy starch.…”

Developing Winter Food Barley for the Pacific Northwest of the US

“…The hull-less trait (where the lemma and palea do not adhere to the hull) is recessive and is determined by allelic variation at the nud locus. After assessing food lines with a spring growth habit under dryland conditions in the PNW, Rey et al (2009) also concluded that hulled lines had greater yield potential and increased vigor than hull-less lines. Pearling is the process of physically abrading the grain to remove the outer tissues including the hull, bran, and germ.…”

β-GLUCANS CONTENT AS A PERSPECTIVE TRAIT IN THE BARLEY BREEDING FOR FOODSTUFF USE (review)

“…Thus, it was found the unstable obviously negative correlation between the accumulation of -glucans in barley grain, on the one side, and 1000-grain weight (78,91), contents of amylose (77,82,83,97), starch (60), percentage of ash (79), grain yield size (82, 88) -on the other. In oat it was observed a strong positive correlation between -glucan content in grain, on the one hand, and the protein content and natural weight -on the other, as well as the negative correlation between accumulation of β-glucans and duration of the period germination-seedlings (87).…”

“…-Glucan content in grain is largely determined by the genotype and climatic conditions of plant growth (55,(76)(77)(78)(79). Some researchers show that genetic factor has the largest contribution in variation of -glucan content (53,(80)(81)(82)(83)(84), while others assume the crucial importance of environmental conditions (77,85,86).…”

“…As a rule, hulless varieties develop lower average yield than covered cereals. That's why the most promising agronomic varieties (especially in dry climate) are covered amylose-free cultivars capable to realize a potential significant yield with high -glucan content (83).…”