Evaluation of Mustard (Brassica compestris Var. Toria) and Legume Intercropping under 1 : 1 and 2 : 1 Row-Replacement Series Systems

Abstract

The non-starch polysaccharide β-(1-3), (1-4)-D-glucan, a component of the cell walls of barley, has been implicated as being involved in the ability of barley to reduce serum cholesterol. However, high β-glucan content in malt is a major production problem in brewing and contributes to hazing of beer. The objective of this study was to examine the developmental pattern of β-glucan content during grain filling for different barley cultivars (Hordeum vulgare) and wild barley (H. spontaneum) lines. In 1994 and 1995, 10 German two-rowed spring barley cultivars and four lines of wild barley were tested in field studies. From the beginning of the grain-filling period onwards, the β-glucan content increased steadily until approximately 500 growing degree-days (GDD) after anthesis or until 35-30 % water content had been achieved. Thereafter the β-glucan content did not alter substantially. Cultivars had β-glucan contents of between 3.9 and 4.8 %. During storage over a period of 6 months after harvest, the β-D-glucan content was stable or increased slightly. Some H spontaneum lines had glucan contents 2-fold higher than those of the cultivars, while others had glucan contents in the same range as those of the cultivars. H. spontaneum lines showed large genotypic differences in the developmental pattern of β-glucan increase during grain filling. The highest rates of β-D-glucan increase occurred at the beginning of the grain-filling period. At this time the β-(1-3), (1-4)-glucanase activity was also highest. Glucanase activity decreased for all cultivars and H. spontaneum lines during grain filling. This reduction continued until 500 GDD after anthesis, or until a caryopsis water content of 35 % had been reached. Of all the genotypes tested, H. spontaneum line 41936' had the highest β-D-glucan content and the highest glucanase activity during grain filling.