| The quality improvement in malt barley is utmost important for further enhancement of the competitive ability on markets as well as production in China. Malt extract, kolbach index, diastatic power and malt viscosity are the major traits closely related to the quality of malt barley, and they themselves are dominantly affected by carbohydrates, protein content and their components, and the relevant enzymes in grains. Among them, protein and -glucan contents, -glucanase and -amylase activities have been considered the principle factors affecting malt quality. The research was carried out to determine cultivar and environmental variation of these four characters and illustrate their relationships with some malting qualities. In addition, The NIR ( near infrared) models for analyzing barley grain protein and p-glucan content were also investigated. The main results are as follows:1 The cultivar and environmental variation of some malt qualities and their relationships in malt barleyThe differences among cultivars and environments (years and locations) in some malt qualities were studied by using eight barley cultivars grown at seven locations with quite diverse ecology in the southern China for successive two years. The results showed that there were highly difference in malt qualities among cultivars, locations, years and their interactions, except for no difference between years in diastatic power. On an average of two years, malt extract of 8 cultivars over 7 location ranged from 75.69% for Zheyuan18 to 78.84% for Ganpi1, and from 73.03% in Taian to 80.55% in Nanchong for 7 locations over 8 cultivars; diastatic power of 8 cultiavrs ranged from 283.43WK for Zhepi 4 to 341.93WK for Yanyin 1, and from 258.19WK in Nanchong to 368.38WK Taian for 7 locations; Kolbach index of 8 cultivars ranged from 34.29% for Zheyuan 18 to 44% for Daner barley, and from 30.00% in Taian to 44.75% in Nanchong for 7 locations; malt viscosity of 8 cultivars ranged from 1.48cP for Daner barley to 1.70cP for Zheyuan 18, and from 1.48cP in Hangzhou to 1.72cP in Taian for 7 locations. The analysis of correlations showed that malt extract was significantly positively correlated with kolbach index, and significantly negatively correlated with diastatic power and malt viscosity. Diastaticpower was highly positively and negatively correlated with malt viscosity and kolbach index, respectively. Kolbach index was highly negatively correlated with malt viscosity.2 Cultivar and environmental variation in barley -glucanase activity -glucanase activity in barley grains was relatively low. Averaged over all cultivars, location and years, the mean 3-glucanase activity in barley grain was 69.26U/kg, with the range of 25.77U/kg for Guanpi 1 in Zhengzhou (2000 year) to 174.99 U/kg for ZAU3 in Nanchong (2001 year). There was significant difference in grain 3-glucanase activity among cultivars, locations, years and their interactions. During malting P- glucanase activity showed a substantial increase. Thus, the total mean of the enzymatic activity was 354.46U/kg, with a range of 217.64U/kg for Yanyinl in Zhengzhou (2001 year) to 624.01 U/kg for Daner barley inJingzhou (2000 year). Similarly, the effects of cultivar, locations, years and their interactions on malt 3-glucanase activity were all highly significant, with the cultivar having the largest effect. It appears that malt p-glucanase activity is mainly determined by cultivar.3 The function of -glucanase on -glucan degradation and its relationships with other malt qualities -glucan content in malts was dramatically reduced, in comparison with that in grains. On the whole, nearly 80% of total p-glucan content present in grains was degraded by p-glucanase during malting. However, obvious differences among cultivars and locations existed in the reduction of -glucan content during malting, -glucan content in malt was more dependent on its degradation during malting than the original level in grains. That is, -glucan content in malt was greatly dependent on -...
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