Cultivation Measures For High Yield And Good Quality Of Malt Barley Variety Yangnongpi 2 And Relevant Mechanism Analyses

The effects of nitrogen application and plant density on grain yield and quality as well as malting quality in malt barley variety Yangnongpi 2 (H.vulgare.l) were studied on the experiment field of Crop Cultivation and Physiology Key Laboratory of Jiangsu Province, Yangzhou University from 2001-2002. The main results were as follows.1. The amount and basal: top dressing ratio of N application and plant density could significantly affect grain yield. When the applied N amount was less than 225 Kg/ha, biomass at maturity and grain yield could rise with the increase of N application amount, and grain yield was positively correlated with the applied N amount. But, if N application amount exceeded 150 kg/ka, the economical efficiency would decline resulting from the decrease of nitrogen harvest index (NHI). With the same nitrogen application, grain yield could be positively related to plant density ranging from 150 X 104/ha to 225 X l04 /ha plants, caused by the increase of spike number, but negatively to plant density surpassing 225 X 104/ha plants because of the sharp decrease of grain weight.Under the same nitrogen application amount and plant density, basal N rate expressed a quadratic curve correlation with grain yield, y=56.351 x X2+369.538X+7484.5 (r=0.82). As can be seen from the equation, basal: top dressing N 7:3 was found to be optimum.The effect of N application amount and basal: top dressing ratio and plant density on spike number was much greater than that on grain number per spike and grain weight. But spike number was negatively correlated with grain number and grain weight. So excessive spike number would cause less kernel number and lighter grain weight, which resulted in lower grain yield.2. N application amount, basal: top dressing N ratio and plant density had significant influences on grain quality. Grain protein content increased with the raise of nitrogen application amount or top dressing nitrogen amount. Specific grain weight would decrease with the increase of nitrogen application amount exceeding 75kg/ha.Under the same nitrogen application method, grain starch content could rise with the increase of plant density, while grain protein content and the accumulating rate ofprotein decreased. The plant density of 225 X 104/ha was beneficial to producing high-quality malt barley. Appropriate basal: top dressing nitrogen ratio could result in unanimous grains in weight, great specific grain weight and germination percentage and potential .Protein content and the accumulating rate of protein in grains showed a "w" type dynamic N application amount, plant density and basal : top dressing N ratio significantly affected protein accumulation from the 7th ,14th and 21st day after anthesis on, respectively.3. Grain quality affected by N application and plant density could directly influence malting quality. Grain protein content was negatively correlated to steeping degree and steeping rate, and positively related to saccharogenic power. The relationship of grain protein content to a -Amino-nitrogen content and kolbach index could be expressed with a quadratic curve equation, respectively. The greatest decomposition rate of protein might be achieved when grain protein content was 11-12%. According to the experiment results in this paper, grain protein content 10%- 12%, starch content 57% and grain weight 45-47g/1000 grains could yield best malting quality.4. It might be concluded that 150kg/ha N, 225 X 104/ha plants, basal: top dressing N 7:3 could be the optimum integrated cultivation measures for malt barley variety Yangnongpi 2.