Comparison Of The Grain Quality Characteristics Between Two Wheat Cultivars With Different Quality Traits As Affected By Altering Radiation

The experiment was conducted at the research farm of Shandong Agriculture University from 2001 to 2002.Two winter wheat(Triticum aestivum L.)cultivars,Yannong No.15(YN15)and Lumai No.21(LM21),were used to study comparison of the grain quality characteristics between two wheat cultivars with different quality traits as affected by altering radiation. The main results were as follows:1. The characteristics of carbon metabolism of different winter wheat cultivarsLM21 had higher photosynthetic rate of flag leaves after anthesis than YN15. Sucrose phosphate synthase (SPS) activity of flag leaves of LM21 was lower than that of YN 15 from 17th day before anthesis to 14th day after anthesis, but was higher after that. The content of soluble sugar in flag leaves and stem and leaf sheath of LM21 were all more than that of YN15 after anthesis. The changes of dry matter of two cultivars were similar. However, the proportion of each vegetative organ that accounts for whole was different.And that of spike of LM21 was greater than that of YN15.General starch of LM21 was higher than YN15 by content, among them YN15 amylose lower than LM21, the content of amylopectin higher than LM21. Sucrose synthase (SS) activity in kernel of two cultivars was very much little different. The above-mentioned results indicated that LM21 carbon metabolism characteristic was superior to YN15.That was physiology foundation for weight per 1000 kernels and number of kernels per spike of YN15 less than notably LM21.2. The characteristics of nitrogen metabolism of different winter wheat cultivarsThe activity of nitrate reductase (NR) in flag leaves of YN15 was much higher than thatof LM21, especially 14th after anthesis. The content of nitrogen at anthesis of vegetative organs of YN15 were all more than that of LM21.The allocation of nitrogen of every vegetative organ at maturity was similar to that at anthesis, but the amounts remarkbly droped. The nitrogen contribution of every vegetative was distinct, the sequence of nitrogen contribution was: stem and leaf sheath >other leaves>flag leaves. Amount and rate of contribution of YN15 were more than LM21 in every the vegetative organs contribution, especially flag leaves.The contents of protein of YN15 were higher than LM21 at every stage of grain filling .The content of protein components of YN15 were also highter. GMP of two cultivars began to accumulate 14th after anthesis, which of YN15 remarkbly were more than LM 21.3. Differences of grain quality and yield of different winter wheat cultivars With regard to grain test weigh,wet gluten content ,Zeleny Sedimentation volume,farinograph index,extensograph index, YN15 was superior to LM21.The yield of LM21 was significiantly more than YN15 and the yield components of the grains per spike and the grain weight were wholly remarkbly more than YN15.4. Effect of intensity shading on carbon nitrogen metabolism as well as grain quality and yieldThe carbon metabolism was depessed after shading. The photosynthesis rate of flag leaves cut down, dry matter per stem decreased, the soluble sugar content in flag leaf and stem and leaf sheath became lower, SS activity of kernel remakbly declined, and the starch content decreased too. The range of changes became larger with increasing of the shading intensity.The activity of NR decreased after shading, so the capability assimilated nitrogen abated. The reallocation of nitrogen in the nutrition organ changed at maturity, nitrogen in leaves is usually held up in reducing. The nitrogen is held up in increasing in both the stem and leaf sheath. But nitrogen contribution rate of every nutrition organ to kernel increased. The content of protein, protein components and GMP all increased. But the protein accumulation amount decreased at once after shading. That demonstrated the increase of the protein content was caused by the decline of the starch accumulation rate.Some quality indexes of the wheat were improved after shading that hold from anthesis to maturity for different i...