Study On The Theory And Practice Of Maize Super High Yield Breeding And Its Optimization Of Cultivation Techniques

The increasing of maize production only depends on the growth of yield in unit area, and the growth of yield in unit area comes from innovation of technology. The essence of innovation of technology is the innovation of method and technique process. Through innovation of materials, methods and technique process, the innovation of production will be realized. The best economic and effective method for innovation of production is breeding. By improvement of varieties and optimization of cultivation techniques, a technological model for high-yield and high-performance will be formed, and by which the efficiency of measures will be achieved. The study includes the following contents:1. It comprehensively expounds the overview of domestic and foreign maize production, breeding history and status quo, breeding tendency and the actualities of optimization of cultivation techniques. We will realize our shortage in maize breeding, cultivation technique and production between China and advanced countries. That would become the rationale to solve the problems.2. Maize is a naturally cross-pollinated crops. The heterozygosis of its hereditary basis make maize breeding a special process, which contains separating and screening selecting inbred lines, mating hybrid and utilizing the heterosis of their F₁ generation. It's necessary to clear up the basic theory of maize breeding in order to grasp elementary knowledge of maize breeding. The process of maize breeding is accomplished by confirming the goals, screening the original materials, using appropriate selecting methods and correlative appraisal programs.3. I have worked on maize breeding for 20 years since 1988. I have developed 10 new maize hybrids as the first breeder. They are: Liaodan 30,31,34,565,566,568,573,526,527 and silage maize Liaodan Qingzhu 529. Four of them have been examined and approved by National Committee, and six of them have been examined and approved by Liaoning Provincial Committee. These hybrids were developed completely according to the above breeding theory and practice. This thesis expounded not only the breeding process of above 10 hybrids, thinking of materials screening and selecting techniques but also the inspiration, the experiences and lessons to future breeding. All of theses will guide the successors on maize breeding.4. Maize super high yield breeding was brought forward based on the breeding theory and practice. The new breeding program will make distinct improvement on maize yield, quality, resistance and adaptability. The essence of super high yield breeding is, indeed, to make higher breeding targets. In order to realize these targets, we must innovate breeding methods and technique process. The general guiding ideology is as follow: under the direction of heterosis theory, change breeding strategy from pursuing individual to population higher yield, so that not only the density-tolerance and wide adaptability of hybrids are improved but also the production cost is decreased. Utilizing different technologies of crop heterosis, plant type improvement and molecular biology, we can organically integrate high combining ability, ideo-plant type, multi-resistance with wide adaptability, super hybrid maize will be achieved by recycling breeding strategy. The indices of ideo-plant type, technologies of material selecting, improved breeding techniques and regional appraisement were developed through super high yield breeding practice. And the advancement of super high yield breeding was described at last.5. Research on optimization of cultivation techniques was done using three maize hybrids as representatives (Liaodan 565, Liaodan 526 and Danyu 39) in Jinzhou, Fuxin and Haicheng. The experiment includes five cultivation modes (convention planting, double line at one width ridge, wide/narrow row alternation, narrow row spacing and short planting spacing, two/one row interval planting ) and four densities (52500 plants/hm², 60000 plants/hm², 67500 plants / hm² and 75000 plants / hm²). The optimization of cultivation techniques of different hybrids was found by comparing their agronomic traits, physiological indices and ear characters in different cultivation mode. Liaodan 565 is a hybrid with high and stable yield if you change cultivation mode and increase density. Its cultivation mode can be selected according to local natural environment. Double line at one width ridge or narrow row spacing and short planting spacing are usually better choices, with planting density 67500-75000 plants/hm². Liaodan 526 has higher plant height and ear height. Its adaptability is common and variable in different area. It would be better using narrow row spacing and short planting spacing or double line at one width ridge with planting density 60000 plants/hm² in West Liaoning, and using convention planting or double line at one width ridge in South Liaoning with planting density 60000-67500 plants/hm². Danyu 39 has good adaptability with no harsh requirements to cultivation mode. But if you want best yield, you should adopt double line at one width ridge, narrow row spacing and short planting spacing, or wide/narrow row alternation, with planting density 60000-67500 plants/hm².6. The study shows the problems of maize breeding and how to enhance research of cultivation techniques. Only when we match good variety with suitable cultivation techniques, will an increase in grain production finally come true.