Screening Allelopathic Rice Varieties By The Inhibit Ring Method In Field Test

In this paper,the allelopathic potential of 132 rice varieties(Oryza sativa)was screened by the weed inhibitory circle method in field test.The physiological indices of rice cultivars and barnyard grass(Echinochloa crusgalli)were determined.And the correlation between inhibitory rate of barnyard grass and the morphological indices of rice and barnyard grass were analyzed.The main results were as follows:The cluster analysis of primary screening results showed that 20 out of 132 cultivars could be chosen to screening again.Those were 10 higher allelopathic potential cultivars(inhibitory rates on the fresh weight>59%)of ai mei zao number 2,xiang nuo,guo xiang number 4,Ollwae do,8303,ye ao si miao,bo B,wu xiang number 1,488,xie qing zao B,5 middle allelopathic potential cultivars(56%>inhibitory rates on the fresh weight>38%)of SG-08049,Acc8518DE192,84ve314,tai bei number 118,san lu zhan 7,and 5 weak allelopathic potential cultivars(inhibitory rates on the fresh weight<36%)of Man sin,ta xian,Iari-7130,qing xiang wan,Naoemzo(b)70.By the two times of screening results,the five cultivars,which were Ollwae do,ye ao si miao,488,xie qing zaoB,bo B,were be clarified as higher allelopathic potential cultivars.The five varieties were above 20%of inhibitory rates on the plant height and above 54%inhibitory rates on the fresh weight,both in the two tests.These five higher allelopathic potential cultivars which obtained from repeat screening in the field were experimented in pot,the results showed that there were above 20%of inhibitory rates on the plant height and above 35%inhibitory rates on the fresh weight.The inhibitory rates of five kinds of rice varieties experiment in the field and indoor were reached extremely significant level.Under rice seedlings cocultured with barnyard grass,rice influenced the biomass and the plant height accumulation of barnyard grass.The effect degree on the plant height were significant greater than the biomass.However,the protective enzyme activity of rice seedlings was not significant influence by barnyard grass.There was no significant correlation between the inhibitory rate of barnyard grass plant height and rice physiological indices.The correlation was different among the transplanted time of barnyard grass.In the first field screening experiment,,it was negative correlation between the inhibitory rate of barnyard grass plant height and the plant height,N content,chlorophyll content,and the length of the second internode leaf of rice seedlings when one week of barnyard grass transplanting.And is was positive correlation between the inhibitory rate of barnyard grass plant height and the plant height and the length of the second internode leaf of rice seedlings,while was negative correlation with the N content,chlorophyll content,and the width of second internode leaf of rice seedlings when two week of barnyard grass transplanting.And when three week of barnyard grass transplanting,only the plant height of rice seedlings was negative correlation with the inhibitory rate of barnyard grass plant height,and others were positive correlation.The second field tested results were similar to the first in most indices,however,all the indices of rice seedlings were negative correlation with the inhibitory rate of barnyard grass plant height.The correlation analysis showed the there were similar results between the two time experiments.They were positive correlation between the inhibitory rate of barnyard grass plant height and the inhibitory rate of dry weight and fresh weight of barnyard grass plant,and negative correlation with the N content and chlorophyll content of barnyard grass.In summary,5 rice varieties with strong allelopathic potential were screened from 132 rice varieties,which provide new rice germplasm material for allelopathic rice research.