Differences Between Yieid And Quality Of Different Genotypes Soybean And Its Adjustment Of Nitrogen

The experiment which used different genotypes soybean Heinong44, Heinong48 and Dongnong4400 as materials was done in test and practice base of northeast agricultural university from 2007 to 2008. The experiment studied the physiological differences between the yield and the quality of the three genotypes soybean and studied the effect of nitrogen levels(0 kg/hm2,50 kg/hm2,100 kg/hm2) and nitrogenous fertilizer postponing (flowering stage, pod bearing stage, seed filling stage) on the it through the method of plot experiment. The conclusions showed as follows:1,Differences between yield and quality of different genotypes soybeanYield and quality of different genotypes soybean showed as follows: Heinong48 had the highest yield and protein content. The yield of Heinong44 was in the middle, but the fat content was the highest. The yield of Dongnong4400 was the lowest.The Physiological differences between species showed as follows: the activity of nitrogen metabolism in Heinong48 was high, so was the total nitrogen content, the nitrogen metabolism was strong. higher C / N, with better coordination of carbon and nitrogen; grain higher IAA content, the promotion of the grain plumpness; better yield traits, the highest N harvest index, which reached the highest yield, the highest protein content.2,Effect of nitrogen levels on soybean carbon metabolism capacityNitrogen can promote the activity of invertase at flowering stage and at seed filling stage. Moderate nitrogen can improve the activity of sucrose synthase at seedling stage and at the beginning of seed filling stage. Nitrogen increased the content of chlorophyll a, b and the total content at the beginning of flowering stage, but it presented differences, in other periods because of the variety and different nitrogen levels.N application can increased leaf starch content and lower stem soluble sugar content at flowering stage, lower the leaf soluble sugar content in the mature period. And lower the pod shell soluble sugar content at the beginning of seed filling stage. The effect of nitrogen was different at different growth stages.3,Effect of nitrogen levels on soybean nitrogen metabolismNitrogen can increase nitrate reductase activity, and the effect was the most obvious in the peak period. Nitrogen increased the leaf glutamine synthetase activity at the seedling stage and at seed filling stage of Heinong44, the effect was better when the nitrogen rate was the 50 kg/hm~2 .and it increased glutamine synthetase activity of Heinong48 when the nitrogen rate was 100 kg/hm~2.4,Effect of nitrogen levels on soybean nitrogen accumulation and translocationNitrogen increased total nitrogen content in leaves and stem, the nitrogen effect was different at different varieties and stages. Nitrogen reduced the nitrogen harvest index of Heinong44 and Dongnong4400, but increased the index of Heinong48.When the nitrogen rate was 100 kg/hm2, it increased the storage of nitrogen in three soybean genotypes on the total contribution rate of grain; When the nitrogen rate was 50 kg/hm2 it increased the storage of nitrogen on the total contribution rate of Heinong44 and Dongnong4400 and reduced the storage of nitrogen on the total contribution rate of Heiong48.5,Effect of nitrogen levels on soybean endogenous hormonesNitrogen can adjust soybean endogenous hormone systems. Compared with non-N, N treatment reduced IAA, GA3, ZR, ABA content of leaves at seedling stage; When the nitrogen rate was 100 kg/hm2, it increased the IAA content of leaves but reduced leaf ABA content at reproductive stage When the nitrogen rate was 50 kg/hm2 it increased the ZR content of leaves at reproductive stage.Nitrogen increased the IAA content in soybean grain, the effect at the mature stage was more obvious than at seed filling stage which increased GA3 content at the mature stage. When the nitrogen rate was 100 kg/hm2, the effect was more obvious; when the nitrogen rate was 50 kg/hm2, ZR content increased at the mature stage. when the nitrogen rate was 100 kg/hm2, ZR content increased at the mature stage and at seed filling stage.Because of nitrogen, the value of IAA/ABA,GA3/ABA,(IAA+GA3+ZR)/ABA in grain promoted at seed filling stage and at the mature stage.6,The adjustment of nitrogen levels on carbon and nitrogen metabolism.Nitrogen reduced the C/N in leaves and stem. When the nitrogen rate was 50 kg/hm2, the effect on stem was obvious. When the nitrogen rate was 100 kg/hm2, the effect on leaves was obvious. The C/N in roots lower before seed filling stage and the effect was not obvious after seed filling stage.7,Effect of nitrogen levels on yield traitsPlant height, pods per plant and full grain number were increased and bottom-pod height and podded node were decreased by applying nitrogen.Plumpness rate of soybean seeds was improved by applying appropriate amount of nitrogen(50 kg/hm2).8,Effect of nitrogen levels on soybean yield and qualityNitrogen increased the soybean yield. When the nitrogen rate was 50 kg/hm2, the yield was the highest of Heinong44 and Heinong48. When the nitrogen rate was 100 kg/hm2, the yield of Dongnong4400 was the highest.Nitrogen increased the fat content of Heinog44 and reduced the fat content of Dongnong4400. When the nitrogen rate was 50 kg/hm2, the fat content of Heinong48 increased. When the nitrogen rate was 100 kg/hm~2, the fat content of Heinong48 lowed.Nitrogen reduced the protein content of Heinong44 and Dongnong4400, but increased the protein content of Heinong48. When the nitrogen rate was 50 kg/hm2, the protein content of Heinong48 was the highest.9,Effect of nitrogenous postponing on soybean yield and qualityCompared to none-nitrogenous postponing, nitrogenous postponing reduced the yield of Heinong48 in the level of nitrogen fertilization. The reduce degree of nitrogenous postponing was largest at R1 stage, that was, 10.37 %. Nitrogenous postponing (T1) reduced the yield of Dongnong4400 and increased the yield of Heinong44 at R1 stage. Nitrogenous postponing (T2) increased the yield of Heinong44 and Dongnong4400 at R3 stage and Nitrogenous postponing (T3) increased the yield of Dongnong4400 but reduced the yield of Heinong44 at R5 stage.Nitrogenous postponing increased the protein content of Dongnong4400 and reduced the protein content of Heinong48. The protein content of nitrogenous postponing (T2) was the highest at R3 stage. With the time of nitrogenous postponing delayed, the protein content reduced. The protein content of Heinong44 declined with the nitrogenous postponing (T1) at R1 stage and with the nitrogenous postponing (T2) at R3stage. The protein content of Heinong44 increased with the nitrogenous postponing (T3) at R5stage.The fat content of Heinong48 declined with the nitrogenous postponing. With the time of the nitrogenous postponing delayed, the effect became more obvious. The fat content of Heinong44 increased Dongnong4400 was opposite with the nitrogenous postponing at R1 stage. The fat content of Heinong44 and Dongnong4400 declined with the nitrogenous postponing at R3 stage,but promoted at R5 stage.