Evaluation Of Agronomic Traits And Quality Characteristics Of Rice Germplasm Resources In Cold Regions

A field experiment was conducted to analysis the major agronomic characters and quality characters of 205 rice varieties(germplasm resources)in cold region.The study aimed to explore the relationship between the agronomic characters of the stems,leaves and panicle of rice and quality characters,analyze the changes of the quality and agronomic characters of the rice varieties bred in different years,screen excellent characters of rice germplasm,and provide basis for rice breeding and cultivation in cold region.The main results were as follows:1.The major agronomic traits of the tested varieties displayed rich genetic variation.The biggest variation of stem,leaf and panicle characters was the length of the inverted 3 nodes,the inverted 1 leaf base angle and the second branch number,and the coefficient variation of that was 22.28%,63.87% and 31.27% respectively.There was a significant positive correlation among the main agronomic traits.The tested varieties were divided into 4 groups by cluster analysis,the plant height of group II was highest with an average height of 96.81 cm and the plant height of group ? was lowest with an average height of 76.77 cm.Group III had longer sword leaf and larger area of sword leaf;Group IV had smaller inverted l leaf base angle and erect plant type.2.The analysis of quality characters of rice in cold region showed that the coefficient variation of chalkiness was the largest,reached 87.63%.There were different correlations among different quality traits.Brown rice rate,milled rice rate and head rice rate were significantly negative correlated with chalkiness rate and chalkiness degree.The tested varieties were divided into 4 categories by cluster analysis.The head rice rate of group I was highest,reached 67.3%.The chalkiness degree and chalkiness rate of group I were lowest,the value of them was 2.83% and 5.07% respectively.The group I had better processing quality and better appearance quality.The grain length of Group II was shortest,just reached 4.58 mm.The rice taste value of Group II was highest,reached 73.01 Group II had shorter grain type,but the cooking quality of this group was excellent,and the taste of this group was good.The head rice rate of group III was lowest,just reached 52.18%.The protein content of group III was highest,reached 9.79%.The milled quality of the group III was poor,but the nutritional quality of this group was better.The grain width of group IV was minimum,just reach 2.87 mm.The rice taste value of group IV waslowest,just reached 66.54.The grain type of group IV was slenderness,and the cooking and eating quality was not good.3.Correlation analysis of agronomic traits and quality traits showed that the milled quality and appearance quality of rice germplasm with thicker inverted 1 and inverted 3 inernodes were better.The leaf base angle had great influence on the quality traits,and the rice germplasm resources with smaller leaf base angle and erect leaves whose milled quality and appearance quality were good and rice taste value was higher.The panicle characters had the greatest influence on the milled quality,and there was a significant positive correlation.The kernel setting rate of primary branches and the kernel setting rate of the second rachis-branches had great influence on the appearance quality,and there was a significant negative correlation.4.The milled quality,appearance quality and cooking quality of rice varieties in cold region were improved by breeding.With the succession of varieties,the plant height decreased gradually,the internode length became shorter,internode thickness decreased,the length of flag leaf became shorter,length and width of inverted 3 leaf increased gradually,upright nature of leaves became better,the total grain number,total grain weight,full grain number and full grain weight increased,the kernel setting rate of primary branches and the secondary branches increased gradually.5.The classification and identification of the quality characters of rice in cold region showed that the brown rice rate was mainly distributed in grade 1 and 2,the milled rice rate was mainly distributed in grade 1,the chalkiness rate was mainly distributed in grade 1and 2 and the chalkiness degree mainly distributed in grade 2and 3.6.By identifying and evaluating the agronomic characters and quality characters of rice germplasm in cold region,4 dwarf resources,5 lodging resources,6 long flag leaf resources,28 long panicle resources,4 long grain resources,90 high milled rice rate resources,5 low chalkiness rate resources,5 low protein content resources,8 high rice taste value resources were screened and used.