Physiological basis for allelopathic potential of different wheat cultivars in heading period on the Loess Plateau of China

The relationship between fluorescence kinetics and allelopathic expression of four winter-wheat ecotypes in heading period was discussed. With the breeding history from No. 1 Bima, No. 3 Fengchan, No. 1 Ningdong to No 22 Xiaoyan and agronomic properties of winter wheat like thousand seed weight and yield, etc increased gradually. Meanwhile, allelopathic potential was also enhanced. It was explained well by physiological basis of fluorescence kinetics. Fm' and F was induced to increase, furthermore, photosynthesis system PSII would be expressed superiorly under arid press. Significant relationship among growth traits, florescence kinetics and allelopathic potential was discovered. Three kinds of parameters like yield, chlorophyll and allelopathic potential of winter wheat in heading period formed a complex network system. So, allelopathy variation was mainly determined and regulated by the presumed net system in plants. It is important in screening and breeding of allelopathic crops cultivars, including development of sustainable agriculture.