| To investigate the forming Characteristicss of yield and quality of different type wheat cultivars under different conditions, study were carried out in Urumqi, Changji, Mulei in Xinjiang province and Taian in Shandong province from 2002 to 2003. Using the same type wheat cultivars from different sources, the effect of nitrogen application timing on yield and quality of different wheat cultivars and their physical and bio-chemical basis were also studied . The principal results were as follows: 1. Quality characteristics of winter wheat under different zones 1.1 Environment variation of yield of different type winter wheat There were obvious difference between the yield of different type winter wheat, the yield of normal type wheat cultivars were higher than other types, and the yield of hard wheat were lower. And there were difference between the yield in different zones: yield in Mulei > yield in Urumqi >yield in Changji. The effects on wheat yield of different ecological conditions were different significantly. Compared with other types, its effects on normal type wheat cultivars were smaller, with comparatively stable yield. 1.2 Dynamic changes of nitrogen and phosphorus in different organs of different types winter wheat The nitrogen contents in leaves, sheath and stem of different type winter wheat were gradually reduced from anthesis, coming to the lowest at mature stage. The nitrogen content in grain of different type winter wheat first gradually reduced from anthesis, and then rose from 21 days after anthesis, and highest at mature stage. At the stage of mature, the grain nitrogen contents in hard wheat cultivars of GC8901 and XD23 were higher than other two types. The phosphorus contents in leaves, sheath, stem and grain were with a same trends: gradually decreased after anthesis. And there were difference between the phosphorus contents in leaves of different type winter wheat, which likely because of the different phosphorus using characteristics of different type winter wheat cultivars. The phosphorus contents in grain of two Xinjiang cultivars were higher than two cultivars introduced into Xinjiang at the early stage after anthesis, while lower at the stage of mature. 1.3 Dynamic changes of grain starch of different type winter wheat The amylase contents of different type winter wheat were with a trend of rise with grouting. The amylose contents of hard winter wheat of GC8901 and XD23 were lower than other two types. The amylopectin contents of different type winter wheat were with a trend of rise with grouting. The rise speed were higher from 14 days to 28 days after anthesis, and then the rise speed were reduced. Among the three different type wheat cultivars, the grain amlopectin contents of hard wheat cultivars, GC8901 and XD23, were higher, while that of soft wheat SN1391 was lowest. The ratio of amylopectin to amylose of different type wheat cultivars were different from each other, those of GC8901 and XD23 were higher than other types. And the ratio of amylopectin to amylose wheat in Changji were higher than those in Urumqi. 1.4 Nitrogen metabolism of different type wheat cultivars in different zone The grain protein content of different type wheat cultivars decreased gradually after anthesis, then increased from 21 days after anthesis, and come to the highest at the mature stage. And the protein contents of different cultivars were different. With the growth of grain, the contents of globulin and albumin were with a trend of decreasing gradually, with those of hard winter wheat lower than others. And the gluten and the gluten to gliadin ratio of hard winter wheat, GC8901 and XD23, were higher than other two types, obviously. The activity of NRase in flag leaf decreased with the grain filling, that of hard wheat cultivars was higher than other types. The GS activity in flag leaf increased after anthesis, and come to the highest in 14 days after anthesis, then decreased, among the three types, those of hard wheat cultivars were higher. The GDH activity in grain increased after anthesis, and come to the highest in 21 days after anthesis, then decreased, among the three types, those of hard wheat cultivars were higher. 1.5 Quality of different type winter wheat cultivars in different zoneThe wet glutin content of two hard wheat cultivars were lower than that of soft wheat cultivars SN1391, but other quality characteristicss, such as falling value, dough development time, and dough stability time were higher than those of soft wheat cultivars SN1391. 2 Effect of nitrogen application timing on yield and quality of wheat 2.1 Effect of nitrogen application timing on yield of wheat The result showed that, the nitrogen application timing had effects on the yield of wheat to some extent, the yield of nitrogen application at joint stage were higher than those application at the stage of green turning and booting, among the last two, which of the former was higher. The protein and gluten contents of wheat were: application nitrogen at booting stage > application at joint stage > application at green returning stage. Thus, there was a conflict between the increase of yield and the increase of protein yield and quality. 2.2 Effect of nitrogen application timing on nitrogen contents in different organs of wheat With the later date of nitrogen application, the nitrogen content in leaves and sheath increased. And the dynamic changes of nitrogen in leaves and sheath were different. At the mature stage, the stalk nitrogen content decreased with the postpone of application timing. It was contrary to grain nitrogen contents. 2.3 Effects of nitrogen application timing on grain starch of wheat With the postpone of nitrogen application, the grain amylase content of wheat decreased gradually, while the decreasing speed of different cultivars were different. But the postpone of nitrogen application, the grain amylopectin content of wheat increased gradually. And the amylopectin content of different cultivars in different zones were different, those in Changji were higher than those in Urumqi. 2.4 Effects of nitrogen application timing on wheat nitrogen metabolism With the postpone of nitrogen application, the contents of albumin and globulin decreased in Xijiang, while the contents of gluadin and gluten increased. And with postpone of nitrogen application, the gluten to gluadin ratio increased, but there were also difference between the different type cultivars in different zones. The activity of NRase in flag leaf increased with the postpone of nitrogen application. And the difference at the early stage of grain formation were larger, while at late stage of grain formation the difference was lower. And the activity of GS in flag leaf increased with the postpone of nitrogen application, those of nitrogen application at booting stage was higher than those application at jointing stage and green turning stage. And the activity of GDH in grain had a same trend with the GS in flag leaf.
|
PDF Full Text Request