To increase brewing yield and efficiency, malts with high extract values, high enzymic activities and good modification are essential. To produce malt that meets these requirements, the barley employed must have minimal post-harvest dormancy and be able to germinate vigorously. The aims of this study were to determine the extent to which some Australian barley varieties changed during post-harvest storage, how these changes influenced germination characteristics, enzyme production and malt quality, and, of the germination tests examined, which gave the best indication of a barley's malting potential. Four commercially grown barley samples were obtained, one from Tasmania and three from Victoria. Each sample was stored at room temperature for one year. At monthly intervals, samples were taken and placed at −18°C. The germinative energy (GE) and germinative index (GI) of these samples were measured. Samples were also micro-malted and the quality of the malt was assessed using standard EBC methodology. Storage at room temperature positively influenced the germination characteristics of all samples, with concomitant improvements in hydrolytic enzyme production during malting and in a number of malt quality parameters. It was found that, of the germination tests examined, the GI consistently correlated with enzyme activities during malting and with various malt quality parameters thus indicating that the GI is a good indicator of malting potential.
Relationships between malting quality attributes and grain yield in segregating populations can profoundly influence the intensity and sequence of trait selection. Consequently, the interrelationships between malting quality parameters predicted by near infrared transmittance (NIT) spectroscopy, grain weight, and grain yield in unselected populations of F2, F3, and F4 breeding lines from 4 barley crosses were examined. The simple and partial correlations between malt extract, protein content, and diastatic power were similar to those reported in previous studies except for a positive correlation between malt extract and diastatic power in the F2 and F3 generations. This positive relationship should enhance selection for improved malting quality in breeding programs. There were no relationships between grain yield and malting quality attributes, which would have an adverse impact on the intensity and sequence of trait selection. The effect of F2 and F3 selection for malting quality on F3 and F4 yield distributions was estimated by comparing the F3 and F4 yield distributions of the entire unselected population with those for the selected populations. Individual selection and sequential independent selection in the F2 and F3 generation for malting quality parameters predicted by NIT spectroscopy and grain weight in 4 crosses generally did not alter the nature of the subsequent yield distributions, yet 78–90% of lines could be discarded and there still existed adequate genetic gain for grain yield in the retained population of potentially good malting quality lines. These results indicate that barley breeders could use NIT spectroscopy to efficiently select in the early generations for malting quality prior to the conduct of yield testing and obtain good genetic gain for both malting quality and grain yield.
In studying the compression of loops of fabric between flat parallel plates, the problem arises of the compression of bends. A ‘bend’ is illustrated in Figs. 1 and 2. Two bends are joined to form a loop. The material is postulated to yield in bending such that the bending moment where B is a bending rigidity, K I the current impressed curvature, and K R the ‘remanent’ curvature. This remanent curvature is the free, or natural curvature in the material caused by its past and present deformation. We study the case when the remanent curvature that is, the remanent curvature is proportional to the greatest previously impressed curvature. We call equations (1) and (2) the ‘Remanent Curvature Hypothesis’.
This is an elementary introduction to the type of classical elasticity most likely to be exhibited by fibers. It relates to properties that are independent of direction in certain transverse planes, but which may be quite different in the axial direction that is normal to these planes. A number of aspects of such elasticity are considered. Although textile fibers do not generally meet requirements that enable their mechanical behavior to be described by the classical elasticity model, there are valuable applications of this theory in textile physics.
The dependence on amplitude of the fundamental resonant frequency for the free vibration of a string is derived for the two systems of mounting used in vibroscope measurements. It is found that in both systems a correction term of order e-1(A/l)2 applies, where A is the amplitude, l the gauge length, and e a number we call the incremental strain. As this strain e is usually small (of the order 1% from most textile testing), the correction term can be important at apparently low amplitudes.
Variation within and between F2-derived families for grain yield and malting quality was investigated using F4 breeding lines derived from F2 families of 4 barley crosses. The variation between F2-derived families was greater than within F2-derived families for grain yield and all malting quality attributes. Superior segregates almost exclusively came from the best performing families. The greater similarity of lines eventually drawn from an F2-derived family has significant implications for selection strategies in barley breeding programs as it facilitates the early discard of F2-derived families. To maximise the exploitation of genetic variation as early as possible, selection for malting quality could start in the F2 generation using near infrared transmittance (NIT) spectroscopy and for grain yield in the F3 generation.
The effect of string rigidity on the capstan equation is considered. Two cases which cover the most likely situations are distinguished - contact of the string with the peg at a point, and contact over an arc. The analysis of these situations is facilitated by an approximation derived for the curvature for the leads of string on either side of the peg. If the friction is governed by Amontons' law the correction of the capstan equation for string rigidity will usually be small, but in the case of arc contact and load-dependent coefficient of friction, the correction could be important.
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