Basic Principle and Technique System of Crop Breeding

In this paper, firstly, basic contradiction between suitable ability and yielding-ability of a variety was revealed through abstracting and generalizing a large phenomenon in tests and productions of crops. The basic contradiction and its movement decided yield display of a variety. Yield-ability (or yield potential) of a variety was yield under the most suitable condition for the variety. But in practice the variety had been often planted under relatively unfavorable environment. It had adaptability for conditions. Secondly, nature, action and significance of ecological traits were determined. Comparison tests using of similar isolines of glowing period and pod bearing habit in soybean in multiple years discovered that varieties having suitable ecotype could fuller display its yield ability and gave better yield stability in much years Thirdly, all of yield ability traits and reciprocal relationships among these yield ability traits were determined, mainly on basis of research accomplishments of crop physiology, using axiom method to set up complete theory system of yield ability and net system of trait components. The net system of all traits of seed yield display, basic principle of engineering of crop breeding had been determined, and it revealed both reciprocity among all of ecological traits and yield ability traits of a variety and forming mechanism of seed yield performance. Technique system of crop breeding engineering and suggestions on personnel organization system and division (coordination) in a new type of crop institute were proposed on the basis of basic principle.