Genetic diversity of old french six-rowed winter barley varieties assessed with molecular, biochemical and morphological markers and its relation to BaMMV resistance

Twenty-six old French six-rowed winter barley (Hordeum vulgare L.) varieties were characterized for their reaction against barley mild mosaic virus (BaMMV). The genetic diversity of these varieties and two recent barley varieties was assessed using molecular, biochemical and morphological data. Seven old varieties were fully resistant to BaMMV. A higher differentiation level between varieties was observed by using DNA molecular markers compared to biochemical and morphological ones. Correspondence analysis using all markers showed that DNA molecular data could fully discriminate between all varieties, whereas biochemical and morphological markers were not able to achieve a complete discrimination. The dendrogram clustering computed with the DNA marker dissimilarity index showed two main groups. The first group included the seven varieties resistant to the BaMMV, whereas the second contained susceptible varieties. The relationships between these varieties, their diversity level, and their characterization are discussed. We infer that the seven BaMMV-resistant varieties have a common origin.

Visualization of barley beta-glucan degrading isozymes after gel isoelectric focusing.

A simple method to study the polymorphism of barley (Hordeum vulgare L.) beta-(1-3,1-4)-glucanases (specific enzymes of barley beta-glucan hydrolysis) is described. Proteins of a crude extract of germinated barley kernels were separated in an immobilized pH gradient in two pH ranges (pH 3-10.5 and pH 4-7). beta-glucanases were visualized by contact printing with a polyacrylamide gel containing beta-glucan or lichenan. Patterns of beta-glucanases were revealed by staining with Congo Red with resultant clear zones on a stained background. Various conditions of germination, extraction and visualization were investigated. New isozyme bands could be detected and their nature and origin discussed.

Mapping of ß-glucan content and ß-glucanase activity loci in barley grain and malt.

Genetic study of ß-glucan content and ß-glucanase activity has been facilitated by recent developments in quantitative trait loci (QTL) analysis. QTL for barley and malt ß-glucan content and for green and finished malt ß-glucanase activity were mapped using a 123-point molecular marker linkage map from the cross of Steptoe/Morex. Three QTL for barley ß-glucan, 6 QTL for malt ß-glucan, 3 QTL for ß-glucanase in green malt and 5 QTL for ß-glucanase in finished malt were detected by interval mapping procedures. The QTL with the largest effects on barley ß-glucan, malt ßglucan, green malt ß-glucanase and finished malt ßglucanase were identified on chromosomes 2,1,4 and 7, respectively. A genome map-based approach allows for dissection of relationships among barley and malt ßglucan content, green and finished malt ß-glucanase activity, and other malting quality parameters.