| The term Allelopathy was coined by Molisch in 1937. The rootwords of allelopathy are "allelon" and "pathos" meaning "of each other" and "to suffer", respectively. Therefore, allelopathy means the injurious effect of one upon another including the area of science that deals with the production of allelochemicals, mostly secondary metabolites, by one plant that can either induce suffering in, or give benefit to, another plant. Although the phenomenon has been stated over 2000 years ago and the term has been coined for more than 60 years, as a science, allelopathy is still a new area. The importance of allelopathy has been emphasized only in the last 20 years, when various kinds of ecological and environmental problems were caused by the use of chemical pesticides and herbicides. Studies performed in allelopahty were mainly about bioassay methods, allelochemicals, allelopathic mechanism and its germplasm screening. As a quantitative character of plants, allelopathy is affected by genetic effects and environment conditions such as weather, soil, cultivation and management of field. Accordingly genetic effects and genotype X environment effects of crop allelopathy has been paied great attention to in recent years, however, few information about these aspects especially in genetic ecology has been found.In this study, 5 parental rice varieties with different allelopathic potential were employed in partial diallel cross to get 10 groups of FI seeds. By testing the inhibiting ability of the 5 parents and 10 FIS to root length and shoot length of model receiver plant lettuce(Iac/玞a sativa L.), and by using additive-dominant developmental genetic models, dynamic genetics of rice allelopathy and its genotype X environment effects were analyzed. The results of genetic variance analysis showed that additive and dominanteffect genes express alternatively during six leaf phases, which were from 3-leaf age to 8-leaf age in rice seedling. As inhibiting ability to root length of receiver plant is concerned, additive effect genes prevailed at 3-leaf age, 5-leaf age and 8-leaf age and dominant effect genes were more active at 4-leaf age, 6-leaf age and 7-leaf age. However, genetic effect of inhibiting ability to shoot length of receiver plant was different, additive effect genes were pronounced at 7-leaf age and 8-leaf age, dominant effect genes appeared to play the most important role at 3-leaf age and 5-leaf age but the two effect genes were equally important at 6-leaf age. Heritabilities analysis indicated that either inhibiting ability to root length or that to shoot length of receiver plant, the general heritability in the narrow sense(HN2) decreased with leaf age increasing. Heterosis analysis indicated that heterosis of inhibiting ability to root length of receiver plant was significant in both FI and F2 hybrids at the four stages of 3-leaf age, 4-leaf age, 5-leaf age and 8-leaf age, and heterosis of inhibitory effect on shoot length of receiver plant was significantly obvious in both F] and F2 at the six stages. However, heterosis in F2 was lower than that in F\. Analysis of genetic main effects in 5 parents suggested that Lemont and Dasandyeo were nonallelopathic lines, showing their lower inhibitory effect on target plant, but Taichung Native 1(U), Dular and NC were elite lines exhibiting their high allelopathic breeding value. Analysis of genotype X environment(GE) interaction effect showed that genetics of allelopathy in rice was highly affected by environment, and the interaction between dominant effect genes and environment was significant. Interaction heritability in the narrow sense(HNE2) of inhibiting ability to root length of receiver plant decreased as rice leaf age increased, but H^2 of inhibiting ability to shoot length of receiver plant enhanced with the rice leaf age increasing. Under the condition of lower temperature and weak sunlight, allelopathic heterosis in rice was higher than that under condition of higher temperature and strong sunlight. This implied that plant allelopathic effect could be enh... |
PDF Full Text Request