Effect Of Nitrogen And Potassium On Yield And Quality Of Special-purpose Wheat

The relationship between genotype, fertilizer and grain yield, quality characters inwheat (Tr. aestivum L.) were investigated, and the physiological mechanism and cultural techniques of improving grain quality by using nitrogen and potassium were carried on preliminary analysis on the Experimental Field of Crop Cultivation and Physiological Key Laboratory, Agricultural College of Yangzhou University from 1998 to2001.1 .The range of yield and protein, wet gluten, dry gluten content of grain in the 29 varieties was respectively from 3701.11 kg/bin2 to 8606.11 kg/bin2 and 11.07% to 14.76%, 18.98% to 32.25%, 8.30% to 13.38%. There were eight varieties whose quality characters had been changed too greatly from original area to reach the standards of strong or weak gluten wheat any more among the 29 varieties, according the GB/I 17892-1999 and the GB/B 17893-1999. The results indicated that wheat quality was controlled both by genotype and by ecological conditions, and there also existed significant interactions between genotype and ecological conditions.2. The ratios of basal: top dressing N with 225kg/bin2 application rate greatly affected on grain yield and quality. The treatments of 5:5 showed higher grain yield and protein, wet gluten, dry gluten content and lower starch content than the treatments of 7:3. In the treatments of applying N at different growth stages, the grain yield and quality were late stages>early stages> seeding stage. The treatment of applying N at 9/0 stage had the highest grain yield; The treatment of supplying N at 3/0 stage showed the200141highest test weight, dough stability time, breakdown time and mixing tolerance index. And 1000-grain weight, flour absorption and dough development time were increased by delaying N application. Strong gluten wheat should be delayed N application properly to increase protein and gluten content, and the proper basal: top dressing N ratio was 5:5; the N application for weak gluten wheat should be moved to early and middle growing stages to decrease protein and gluten content.3.Different varieties had different response to K20. I-lu 95-8 needed more K20 than Yangmai 158 for the highest yield. At low or high applied K20 level, the treatments of 5:5(basal: top dressing K20) had higher yield than the treatments of 7:3(basal: top dressing K20), and K20 should be applied at 5/0 to 9/0 stages. The proper applying quantity and time benefited grain yield, nutritional quality and baking quality. If the wheat needed to be improved protein and gluten content, the K20 application should be supplied at 7/0 to 9/0 stages and with 5:5 of basal: top dressing K20; if the wheat needed to be controlled protein and gluten content, the K20 application should be supplied at 5/0 to 7/0 stages and with 7:3 of basal: top dressing K20.4.During grain filling, protein content showed a high-low-high 揤?shape dynamic change and the rate of protein accumulation reached a peak from the 14th to 21st day after anthesis(DAA);the rate of aniylose accumulation reached a peak from the 21St to 28th DAA and the peak of amylose accumulation amount appeared on the 35th DAA; the rate of amylopectin accumulation reached a peak from the 14th to 21St DAA and the peak of amylopectin accumulation amount appeared at mature. Fertilizer could affect the accumulation process of starch and protein. N and K20 applied at the late stage of growth (LSG) could improve the starch accumulation rate of the late filling period and so it increased grain weigh. N and K20 supplied LSG also could improve the protein accumulation rate of the late filling period, which result in increasing protein content. N supplied LSG improved grain amylose content. But If the wheat which need to be improved protein and gluten content, the K20 application should be supplied at 7/0 to9/0 stages and with 5:5 of basal: top dressing K20 applied LSG reduced grain amylose content.5.The results indicated that although special-purpose wheat quality was contr...