Environment and Hybrid Influences on Rapid-Visco-Analysis Flour Properties of Food-Grade Grain Sorghum
Grain processors would benefi t from informa- tion about the production environment and the infl uences of the sorghum (Sorghum bicolor (L.) Moench) hybrid on food-grade fl our proper- ties. The objective of this study was to deter- mine the effects of environment and hybrid on rapid-visco-analysis (RVA) fl our properties of commercially available food-grade sorghum. A randomized complete block experiment was planted in 12 environments, which included the 2004 and 2005 growing seasons and irrigated and dryland water regimes in eastern, central, and west central Nebraska, and a dryland, low-N environment in eastern Nebraska. The environment accounted for 71-85% of the total variation in RVA parameters, while the hybrid accounted for 11-23% and the environment- by-hybrid interaction, 1-3%. Unfortunately, the results of this experiment suggest that it is dif- fi cult to predict the effect that environment will have on resulting sorghum-fl our parameters. Although of secondary importance in terms of total variation in sorghum-fl our RVA properties, the choice of hybrid predictably and signifi - cantly contributes to sorghum-starch viscosity properties. Food-grade hybrids were grouped based on viscosity properties into those best suited for dry-mill and alkaline-cooked prod- ucts (Asgrow Orbit; Sorghum Partners NK1486) and those best suited for porridge, consumable alcohol, and ethanol production (Kelly Green Seeds KG6902; NC+ Hybrids 7W92; Asgrow Eclipse; and Fontanelle W-1000). These results were consistent with those previously reported for grain density.
Plant height response of semidwarf and nonsemidwarf wheats to the environment
Nonsemidwarf wheats (Triticum aestivum L.) are preferred in drought-prone dryland agriculture but are difficult to select under higher rainfall environments where early generation breeding nurseries are often located. To determine the importance of genotype differences in height and the genotype × environment interaction, a combined analysis of variance across three ecogeographic zones was performed using genotype plant height. Genotypes were significantly different and the genotype × environment interaction was significant. Similar results were obtained when the genotypes were classified as semidwarf [gibberellic acid (GA)-insensitive] or nonsemidwarf (GA-sensitive) wheats. The genotype × environment interaction was also partitioned, and the environment × (semidwarf vs. nonsemidwarf wheat), environment × semidwarf wheat, and environment × nonsemidwarf wheat were all significant. The importance of significant genotype × environment interactions is (i) plant height in the eastern Nebraska poorly predicted plant height in western Nebraska, (ii) nonsemidwarf wheats interacted differently than semidwarf wheats with the environment, (iii) plant height should be measured in each ecogeographic zone or at least the eastern zone and either the central or northwestern zone, and (iv) among nonsemidwarf and semidwarf wheats a variety of responses to the environment were found. With regression estimates of stability, semidwarf genotypes were more stable (lower b values) than nonsemidwarf genotypes. Though nonsemidwarf genotypes were on average taller than semidwarf genotypes, semidwarf genotypes with excellent stability could be identified that were not too tall in eastern Nebraska and retained their height in western Nebraska. Nonsemidwarf with similar environmental responses were not identified
SMALL SCALE MASHING EXPERIMENTS WITH GRISTS CONTAINING HIGH PROPORTIONS OF RAW SORGHUM
Small scale mashes (50 g total grist) with grists containing high proportions of raw sorghum (50%–80% malt replacement) showed high values of extract recovery and produced worts of lower total nitrogen, free amino nitrogen, viscosity and colour but higher values of pH compared to worts produced from all malt mashes. Increasing the proportion of raw sorghum in the grist relative to malt resulted in a decline in extract recovery, wort total nitrogen, free amino nitrogen and an increase in wort pH. 
 
 
 
Addition of industrial enzyme preparations to mashes containing raw sorghum resulted in higher values of extract recovery (enzyme preparations containing α amylase and β glucanase), higher values of wort total nitrogen and free amino nitrogen (enzyme preparations containing a neutral proteinase) and decreased wort viscosity (enzyme preparations containing β glucanase or cellulases) compared to worts produced from untreated mashes. 
 
 
 
Worts and beers were produced on a pilot brewery scale from 50% malt and 50% polished (whole) sorghum (single decoction mashing regime) and 20% malt and 80% raw sorghum supplemented with an industrial enzyme preparation (double mashing regime). Mashes comprising 50% malt and 50% polished sorghum showed comparable wort filtration behaviour (lautering) to that of control mashes (70% malt and 30% maize grists) whereas wort produced from 20% malt and 80% raw sorghum filtered slowly. Worts produced from grists containing sorghum were of high fermentability and showed lower levels of total nitrogen and free amino nitrogen compared to control worts. Analysis of worts produced from small scale mashes containing raw sorghum and a pilot brewery scale mash comprising 20% malt and 80% raw sorghum demonstrated that the levels of total nitrogen and free amino nitrogen were higher than expected from the reduction in the malt content of the mash, consistent with the release of nitrogenous components (polypeptides, peptides and amino acids) derived from sorghum into the wort. 
 
 
 
Beers produced from 50% malt and 50% polished sorghum and 20% malt and 80% raw sorghum were filtered without difficulty and were of sound flavour. 
 
 
 
Beers produced from 50% malt and 50% polished sorghum contained lower levels of isobutanol, 2-methylbutanol, dimethylsulphide and higher levels of n propanol and diacetyl compared to control beers.