The Reserch Of Modulating Effects And Its Mechanism For Population Uniformity

Aimed at the larger yield gap among different cultivated land, the lower yield level caused by the imbalance single plant in farm in special district, and lower resource usage efficiency, in order to realize the assumption of the balanced raise of farm yield and resource usage efficiency through enhancing population uniformity in farm, the single plant variation was systematically investigated for the population of different varieties, sowing modes, and different yield level, and the relation between population uniformity and yield. On the basis of above results, the canopy structure and micro-climate factors, the traits of material accumulation and transporting distribution, the yield and quality formation, and the trait of water and nitrogen usage were investigated, and the mechanism of attaining high yield and efficiency were discussed on the basis of modulating rowing space and inner distribution patterns and creating different uniformity population. The main results were as follows:1. The larger difference was existed for the single plant productivity in different population. The spike grains weight was closely correlated with single plant weight coefficient variance. The spike grains weight was raised by reducing the coefficient variance of spike grains weight, and then the yield was increased.The range of spike grains weight in different varieties was0.2-2.2g, and the coefficient variance (CV) of it was24%-34%. The grains weight was negatively related with the single plant weight and grains amount. The direct effect coefficient on the grains weight of the single plant weight was greater than other characters, and it could be used as the index to measure the single plant productivity.The coefficient variance of grains weight of the same variety was different on the distinct cultivating condition (rowing space, sowing mode, water condition), the mean grains weight was lower for the population that the CV of grains weight was higher. The mean grains weight of high-yield population was higher than low-yield population, but the CV of grains weight and other characters was apparently less than the low-yield population.There was great influence of sowing date, rowing space and seed distributing patterns on the single plant character and its CV. The single plant grain weight was a evidently negativly related with the CV plant height, grains and single plant.The CV of single plant character in maturity was apparently decreased, the mean grains weight and population yield were increased through reducing row pitch and raising the seed distribution uniformity.2. The more uniform population was formed by reducing row width and increasing seed distribution uniformity, its canopy structure and micro-environment were evidently improved.The row with was reduced from20cm to10cm, the LAI was apparently increased, and the mean leaf angle (MLA) was evidently decreased. The K was magnified with the increasing for the zenith angle and distributing uniformity. MLA was not evidently influenced by the inner distribution patterns (R and A). The single plant distributing uniformity was increased by narrow rowing space and uniformly planting, and the light interception of the middle-upper situation in canopy was increased, and the light loss in the bottom of population was decreased, the temperature and its variance degree wer decreased, the relative humidity was raised. 3. The population uniformity was improved, and the grains capacity of population, population photosynthesis rate, the amount of material accumulation and its contribution rate to yield were increased after anthesis stage by narrow rowing space and uniformly planting.In the range of10-30cm regardless of early or late sowing date, the sink capacity (spikes x grains) was increased with the reduce of rowing space and the increase of population uniformity, the assimilation amount after anthesis (AA) and its contribution ratio to seed (CAA) were apparently raised. In the same rowing space, the population photosynthesis rate in filling stage was apparently increased with the increase of seed distributing uniformity, the AA and CAA was increased. The high level source-sink capability can be gained by10cm with seed uniform distribution of late-sowing wheat.4. The yield and quality character was improved by uniform population created from the narrow space and uniformly sowing, and the water-nitrogen usage efficiency was increased.The yield of10cm was evidently than20cm, the yield of uniform pattern (A) in15cm and20cm was apparently than the random pattern in the corresponding row. The yield of narrow row with uniformly distributing pattern (10A) was evidently than the random pattern in20cm (20R), the yield was increased22.7-33.1%, and the wet gluten content, dry gluten content, flour stability time were apparently increased. The water consumption, nitrogen assimilation amount were heightened for the treatment of narrow row with uniformly distributing pattern (10A), and above characters were increased apparently in the late growth stage. The water and nitrogen usage efficiency of10A were evidently increased than the20R.The results of integrated study indicated that the production capacity and water-nitrogen usage efficiency of wheat population were improved cooperatively through raising the single plant distributing uniformity. It was an effective measure to improve population’s uniformity, to attain the aim of high yield and efficiency through reducing row width and uniformly sowing under the condition of late-sowing and high-density population in North China district.