QTL Analysis of ß-Glucan Content and Other Grain Traits in a Recombinant Population of Spring Barley.

Barley with high grain ß-glucan content is valuable for functional foods. The identification of loci for high ß-glucan content is, thus, of great importance for barley breeding. Segregation mapping for the content in ß-glucan and other barley grain components (starch, protein, lipid, ash, phosphorous, calcium, sodium) was performed using the progeny of the cross between Glacier AC38, a mutant with high amylose, and CDC Fibar, a high ß-glucan waxy cultivar. The offspring of this cross showed transgressive segregation for ß-glucan content. Linkage analysis based on single-nucleotide polymorphism (SNP) molecular markers was used for the genotyping of the parents and recombinant inbred lines (RILs). Two Quantitative Trait Loci (QTL) for ß-glucan content and several QTL for other grain components were found. The former ones, located on chromosomes 1H and 7H, explained 27.9% and 27.4% of the phenotypic variance, respectively. Glacier AC38 provided the allele for high ß-glucan content at the QTL on chromosome 1H, whereas CDC Fibar contributed the allele at the QTL on chromosome 7H. Their recombination resulted in a novel haplotype with higher ß-glucan content, up to 18.4%. Candidate genes are proposed for these two QTL: HvCslF9, involved in ß-glucan biosynthesis, for the QTL on chromosome 1H; Horvu_PLANET_7H01G069300, a gene encoding an ATP-Binding Cassette (ABC) transporter, for the QTL on chromosome 7H.

Combining Native and Malted Triticale Flours in Biscuits: Nutritional and Technological Implications.

Triticale-based biscuits were formulated with increasing substitution levels (i.e., 0, 25, 50, 75, and 100% w/w) of malted triticale flour (MTF). The products were analyzed for technological and nutritional characteristics, including the evaluation of the in vitro starch digestion. The results indicated that the substitution of triticale flour with MTF increased (p < 0.05) the total dietary fiber and ash contents. Total starch decreased (p < 0.05) when the level of MTF increased in the formulation, causing an increase in reducing sugars and an increase in the starch hydrolysis index and in the in vitro predicted glycemic index (pGI). The hardness and spread ratio values of biscuits decreased (p < 0.05) with increasing levels of MTF in the recipe. The lightness of doughs and biscuits decreased (p < 0.05) with increasing MTF levels. Overall, MTF could be used to formulate biscuits with higher dietary fiber content than native triticale flour and a medium to high in vitro glycemic index value as a function of the substitution level.

Indirect Measurement of ß-Glucan Content in Barley Grain with Near-Infrared Reflectance Spectroscopy.

ß-Glucan is a component of barley grains with functional properties that make it useful for human consumption. Cultivars with high grain ß-glucan are required for industrial processing. Breeding for barley genotypes with higher ß-glucan content requires a high-throughput method to assess ß-glucan quickly and cheaply. Wet-chemistry laboratory procedures are low-throughput and expensive, but indirect measurement methods such as near-infrared reflectance spectroscopy (NIRS) match the breeding requirements (once the NIR spectrometer is available). A predictive model for the indirect measurement of ß-glucan content in ground barley grains with NIRS was therefore developed using 248 samples with a wide range of ß-glucan contents (3.4%-17.6%). To develop such calibration, 198 unique samples were used for training and 50 for validation. The predictive model had R2 = 0.990, bias = 0.013% and RMSEP = 0.327% for validation. NIRS was confirmed to be a very useful technique for indirect measurement of ß-glucan content and evaluation of high-ß-glucan barleys.

Constitutive differences between steely and mealy barley samples associated with endosperm modification.

BACKGROUND: Structurally different areas may occur in the endosperm of the barley grain, and they can be visually classified as either mealy or steely. Barleys with a high proportion of grains that are mostly steely often show uneven physical-chemical modification of the endosperm during malting. To study the relationship between steeliness and endosperm modification, two samples of barley cv. Scarlett with contrasting malting quality were analysed. RESULTS: The proportions of steely grains were 77% and 46% in the two samples, which were then defined as steely sample and mealy sample, respectively. The steely sample showed slower modification during malting (in terms of beta-glucan degradation, friability increase, and Calcofluor staining), lower hot water extract (HWE) and acrospire growth, and higher extract viscosity. Endosperm permeation to large molecules (tested with the fluorescein isothiocyanate-dextran conjugate, FITC-D) closely followed cell wall modification in the steely sample, but this was not so in the mealy sample. CONCLUSIONS: Higher steeliness was associated with higher levels of C hordeins in the grain of barley cv. Scarlett. It is proposed that such hordeins can increase the permeability to large molecules (FITC-D) but slow modification. Like steeliness and the level of C hordeins, permeability to FITC-D appears to be more linked to environmental rather than genetic effects. Although a more general association of C hordeins with steeliness of malting barley still has to be ascertained, the negative role of C hordeins in malting quality has been confirmed.