| The objective of this study was to make clear the structure and function of high yield population and realize quantitative design. The different yield level population were established by different agronomic managements(planting density, tillage systems, fertilizer application and harvest date) during 2009-2011, in Langfang Hebei Province and Xinxiang Henan Province using Zhengdan958, Xundan20 and Xianyu335 as materials, to study the change law of yield performance parameters and explore the regulation effects of key agronomic managements on yield performance parameters, to provide the theoretical basis for establishment of reasonable population structure, and fully development of population function and quantitative design of yield performance. The main results were as follows:(1) The population yield differed significantly establishing by different agronomy managements, the yield were 10.40 t ha-1~11.46 t ha-1 in OPT2(high yield and high efficiency) population, and the yield were 7.88 t ha-1~8.57 t ha-1 in FP(farmer conventional practices), and OPT2 increased yield by 27.58%~38.74% than FP. The yield performance structure parameters for the population of 10.40 t ha-1~11.46 t ha-1 were, mean leaf area index(MLAI) was 2.25-4.45, growth duration(D) was 105-113 d, harvest ear(EN) was 8.00 ears m-2~9.06 ears m-2 and grain number per ear(GN) was 373.49-477.98, and the yield performance function parameters were, mean net assimilation rate(MNAR) was 3.79 g m-2 d-1~7.98 g m-2 d-1, harvest index(HI) was 0.50-0.55 and 1000-grain weight(GW) was 313.75-392.00 g. Compared with the population of 7.88 t ha-1~8.57 t ha-1, yield performance parameters were increased by 30.82%-70.61%, 4.76%-10.00%, 45.23%-77.70%,-2.94%--14.77%,-0.10%--31.26%, 17.94%-27.13% and 2.55%-10.52%, respectively. The contributions of yield performance parameters to yield were 35.92%, 2.41%, 26.27%,-2.21%,-3.30%, 9.46% and 1.49% respectively, and the total contribution was 80.09%, the “over compensation” and“ gain and loss compensation” of the yield performance structure parameters and function parameters was the mechanism of high yield formation.(2) The relationships between yield performance structure parameters and function parameters were analyzed, the yield performance structure parameters and function parameters were optimized, and the relative importance of yield performance structure parameters and function parameters for yield formation were quantified. Grain number per mean net assimilation, yield per mean leaf area index post-anthesis and the grain number per mean leaf index pre-anthesis were the optimizing indicator of the population structure and population function. In the progress of yield improvement, The positive decide effect of mean leaf area index, total grain number per square, total dry matter weight in harvest period, mean net assimilation rate, harvest index, the ratio of trans efficiency of mean net assimilation to mean net assimilation rate post-anthesis, grain number per mean net assimilation rate, yield per mean leaf area index post-anthesis, grain number per mean leaf area index pre-anthesis on yield was 45.47%, 90.14%, 96.67%, 62.44%, 80.32%, 45.29%, 61.67%,, 52.74%, 43.10%, respectively, and the negative decide effect of grain number per mean leaf area index post-anthesis and yield per mean leaf area index pre-anthesis were 48.92% and 41.33%, respectively.(3) Grain yield was increased by 8.96%~11.22% in sub-soiling tillage system than in conventional tillage systems, the effect was more significantly in high planting density population. The main performances were, soil physics traits and soil water content were improved significantly, providing the good soil environment for maize seedling and growth and development; sub-soiling tillage system and planting density had positive interaction effects, in high planting density population, mean leaf area index, leaf area index duration and total dry matter weight were improved significantly but mean net assimilation rate had not significant difference in sub-soiling tillage system, the grain number per mean leaf index pre-anthesis, yield per mean leaf area index post-anthesis and harvest index were decreased with the planting density increased, and the velocities of those were decreased in sub-soiling tillage system. The “asynchronous improved compensation” of yield performance parameters was the main mechanism of formation of high yield in high planting density population in sub-soiling tillage system.(4) Density was determined by two parameters including the maximum leaf area index and the maximum leaf area per plant. And the variation trend of maximum leaf area per plant conformed to Reciprocal model which was proved to have excellent prediction with the mean RMSE was 5.95%. It was learnt from the model that the most suitable maximum leaf area per plant is 0.60 times to the potential maximum leaf area per plant. The main yield performance parameters of different super high yield levels were digital designed based on the calculation of yield performance equation through repeated testing. Through the validation of the model performance with the super high yield of spring maize in Inner Mongolia, super high yield of summer maize in Shandong Province, and super high yield of spring maize in Jilin Province, it was showed that the model had excellent prediction with all the parameters mean RMSE was 7.72%. |
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