Genetic Diversity Of Rice Seeds And Effects Of Microbial Agents On Low Temperature Tolerance Of Rice Seedlings

Rice(Oryza sativa L.)is one of the main food crops in China.Chilling injury is one of the main causes of rice yield reduction in Northeast China.Therefore,it is particularly important to improve the law temperature tolerance of rice and expand the germplasm resources of low temperature tolerant rice lines.In this experiment,the correlation and cluster analy sis of seed phenotypic traits of 9 rice lines were carried out;The indexes of rice germination ability were analyzed statistically;The germination ability of rice was evaluated compretensively,To explore the relationship between the phenotypic traits of rice seeds and the low temperatare tolerance of rice seedlings by microbial agents,in order to provide powerful research data and feasible technical reference for the future research on improving the low temperature tolerance of rice and expanding the low temperature tolerance of rice lines.(1)The phenotypic traits of 9 rice lines were measured and statistically analyzed:In the range of variation,the single seed weight was the largest and the grain length was the smallest,indicating that the single seed weight was more affected by environmental factors,while the grain length was less affected by environmental factors.There were significant differences in all phenotypic traits aomong different lines except single grain weight(P<0.001),which indicated that the phenotypic variation of rice seeds was large,and the difficulty of imp roving these traits by means of selection varied with traits.The single grain weight of seeds was significantly positively correlated with grain length,grain width,grain thickness and grain length width ratio,which indicated that the single grain weight of seeds could be increased by increasing the above phenotypic traits,so as to increase the yield.Cluster analysis sh owed that 9 rice lines were divided into 4 groups,and the phenotypic traits varied gr eatly.The number of high and low temperature tolerant rice lines could be increased through the genetic relationship among different rice lines.(2)In the germination test of rice seedlings,generally speaking,most of the rice lines showed better performance than CK group after inoculated with microbial inoculan ts,indicating that microbial inoculants could improve the low tem perature germination ability and low temperature tolerance of rice seedlings,and the lines X-30 and x-36 showed the best after inodulated with microbial ino culants.The re sults of correlation analysis showed that there was a significant positive correlation between germination potential and germination rate;Plant height was positively correlated with stem diameter and dry weight;Fresh weight was positively correlated with stem diameter,dry weight and water content;The wilt rate was negatively correlated with dry weight,fresh weight and water content.Therefore,the experiment proved that microbial agent can improve the dry weight,fresh weight and moisture content of rice seedlings by increasing the stem diameter and plant height,reduce the wilting rate of rice seedlings,and then improve the low temperature resistance of rice seedlings.(3)In the comprehensive evaluation experiment of rice seed germination ability,X-28,X-30,X-36,X-40,X-42 and X-45 had one or more concentration gradients,and the projection function value of rice was higher than that of CK.The results showed that the effect of microbial agent was significant,and the concentration of A35 agent could im prove the low temperature tolerance of rice.