| The experiment was conducted on canopy morphology structure and photo-physiological characters of high-yield wheat cultivars and correlation analysis between these morph-physiological characters and yield characters of 9 wheat cultivars with different spike types in Guanzhong district of Shaanxi province. The results indicated:1. Cultivars with three spike types such as multi-spike, mid-spike and large-spike all can gain high yield. But comparatively, mid-spike cultivars (600 ten housand/hm2,40-45kernals/spike,40-45g/1000kernals) and large-spike cultivars (450ten-thousand/hm2,45-50kernals/spike,45-50g/1000kernals) had more potential than the multi-spike cultivars in high or higher yield.2. Canopy morphology structure of high-yield cultivars had following traits: wider, shorter and thicker in the top three leaves, smaller slant degree of the leaves, compacter in plant type, short in plant height, longer in peduncle length and sheath length.3. Correlation analysis among canopy morphology characters indicated: The flag leaf had more coherence with top second and third leaves; The basic angle were highly positive correlated with its open and drooping angle; The plant height were no significant correlation with the peduncle length, extrusion length and sheath length; The peduncle length were sigificantly and positively correlated with extrusion length and its sheath length, and sheath length had largely correlated value with spike length. This indicated that short or mid-short cultivars could obtain longer sheath and spike by selecting longer peduncle , meanwhile, short node interval of the plant and improve resistance of falling..4. Correlation anlysis between canopy morpholgy characters and yield characters indicated: Kernels per spike ,1000-grain weight and grains weight per spike all were extremely significantly positively correlated with width,area and specific leaf weight of flag leaves,and the flag leaf's area affected yield characters mainly through the leaf weight and specific leaf weight; Ear number per hm2 were significantly negatively correlated with theslant degree of flag leaf; 1000-grain weight and grains weight per spike were largely negatively correlated with the basic angle and open angle; Grains weight per spike were significantly positively correlated with spike length and sheath length of flag leaf; Grain yield also were highly positively correlated with the peduncle and the sheath length of flag leaf. This indicated the width, specific leaf weight, the slant degree, peduncle length and the sheat length of flag leaf were the restricted characters in deciding yield characters and yield.5. During grain filling stage the high-yield cultivars'LAI, Chl(a+b) content and Pn's decreasing rate and MDA content's increasing rate of flag leaf were more lower than bump-yield cultivar's. Fag leaf had longer LAD , and the Pn was higher and decreasing slowly.6. Correlation analysis among physiological characters indicated: During grain filling stage the flag leaf's Pn were large positively correlated with its Chl(a+b) content, were significantly or extremely significant negatively correlated with it's MDA content; The flag leaf's Chl(a+b) content was largely negatively correlated with it's MDA content.7. Correlation analysis between pnoto-physisological characters and yield and yield characters indicated: 1000-grain weight, kernal numbers per spike, grains weight per spike and grain yield were all significantly or extremely positively correlated with the chl(a+b) content, the Pn and LAD of flag leaf,and were significantly negatively correlated with MDA content.8. By step by step analysis with 24 characters, the result indicated: In contribution sequence, there were four main characters that affected grain yield, such as 1000-grain weight, kernal numbers per spike, ear number per hm2 and Pn of 15d after anthesis; There were four main characters affected ear number per hm2, such as flag leaf area, drooping degree, spike length and the basic... |
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