| Barley is one of the most important cereal crops in the world.Its annual planting area and total output rank fifth in the world,and it has the value of food,feed and industrial brewing.Its nutritional characteristics of high protein,high vitamin,high cellulose,low fat and low sugar "three highs,two lows" have made it as healthy food,which is increasingly valued by consumers.The sustainable development of barley industry is of great significance to ensure food security,plays an important role in promoting the reform of agricultural supply side structure,enhancing agricultural added value and promoting social and economic development.Wild barley is a closely related wild ancestor of barley.It has the characteristics of large grain,high resource efficiency,strong stress resistance,coupled with high genetic diversity,it has always been an important germplasm bank for barley genetic improvement.It is of great value to study the genetic law of barley agronomic traits,excavate and utilize the excellent germplasm and related genes of wild barley to broaden the genetic basis of barley,overcome genetic homogenization and cultivate new breakthrough barley varieties.In order to explore the genetic basis of important agronomic traits of wild barley,a total of 121 RIL populations were constructed using wild barley lines from the origin as male and female parents.The phenotypes of 8 field agronomic traits,8grain-related traits and 8 seedling root traits of the population and parents were investigated.Phenotypic analysis,correlation analysis,principal component analysis and major gene +polygene mixed genetic model analysis were carried out to obtain the correlation between each trait,the optimal genetic model of each trait and its genetic parameters.This study provides a theoretical reference and basis for subsequent gene mapping,candidate gene mining and targeted barley breeding.The main results of this experiment are as follows :1.The field agronomic traits and grain related traits of wild barley RIL population showed different degrees of variation between different years,and the frequency distribution curves was approximately normal distribution.In general,there were extensive variations in 24 agronomic traits.The variation coefficients of field agronomic traits from large to small were as follows : productive tiller number(22.85%),flag leaf width(13.03%),flag leaf length(13.03%),peduncle length(7.77%),spike length(7.72%),grain number(7.39%),spike density(6.33%),plant height(5.92%).The coefficient of variation of grain-related traits from large to small is : thousand grains weight(13.44%),grain area(7.21%),grain roundness(5.6%),grain length-width ratio(5.36%),grain width(4.81%),grain length(4.57%),grain perimeter(4.31%),grain diameter(3.60%);the variation coefficient of root traits at seedling stage from large to small is : root volume(48.76%),root tip number(39.54%),root fresh(32.78%),root surface area(32.56%),root dry weight(31.74%),total root length(28.01%),maximum root length(15.88%),root average diameter(13.24%).All traits had transgressive segregation,showing a continuous variation trend,and the frequency distribution curves were approximately normal distribution.The inheritance was complex and suitable for related genetic analysis.2.The results of correlation analysis showed that plant height,peduncle length and productive tiller number were positively correlated with each other;flag leaf length was positively correlated with flag leaf width;spike length was positively correlated with grain number,grain number was positively correlated with spike density,and spike length was negatively correlated with spike density.Thousand grains weight,grain area,grain perimeter,grain length,grain width and grain diameter were positively correlated.The grain length-width ratio was positively correlated with grain perimeter and grain length,and negatively correlated with thousand grains weight,grain width and grain roundness.Grain roundness was positively correlated with thousand grains weight and grain width,and negatively correlated with grain perimeter and grain length.There was a strong correlation between grain-related traits and spike length and grain number in field agronomic traits.The ratio of grain length to width was positively correlated with spike length.Except for grain length,other grain traits were negatively correlated with spike length.Except for grain length-width ratio and grain roundness,other grain traits were negatively correlated with grain number.The total root length,root surface area,root volume,root tip number,root fresh weight and root dry weight were positively correlated with each other.The root average diameter was positively correlated with root surface area,root volume,root fresh weight and root dry weight,and negatively correlated with maximum root length.The maximum root length was positively correlated with total root length and root tip number.3.Principal component analysis results: A total of 4 principal components were extracted from field agronomic traits,the first principal component reflected the role of panicle,the second principal component reflected the role of plant height,the third principal component reflected the role of panicle density,and the fourth principal component reflected the role of flag leaf size.Two principal components were extracted for grain related traits.The first principal component reflected the effect of grain size,and the second principal component reflected the effect of grain roundness and width.Two principal components were extracted from root traits at seedling stage.The first principal component reflected the effect of root number,and the second principal component reflected the effect of root thickness.4.Analysis results of major gene + polygene genetic model: There were 17 traits in the genetic model of the major gene model,including the plant height genetic model was2MG-ED,and the major gene heritability was 51.00%.The genetic model of peduncle length was 2MG-A,and the heritability of major genes was 65.89%.The genetic model of flag leaf length,grain length-width ratio and root tip number was 2MG-IE,and the major gene heritability was 29.72%,20.65% and 43.17%,respectively.The maximum root length genetic model was 2MG-CE,and the major gene heritability was 39.66%.The genetic model of spikelet number and grain roundness was 3MG-CEA,and the major gene heritability was 23.79% and 13.94%,respectively.The genetic model of spike density and root fresh weight was 3MG-AI,and the heritability of major gene was 24.83% and 94.47%,respectively.The genetic model of total root length and root dry weight was 3MG-PEA,and the major gene heritability was 83.87% and 78.38%,respectively.The genetic model of panicle length was 4MG-CEA,and the heritability of main gene was 33.19%.The main gene heritability of 4MG-AI of grain perimeter,grain diameter and root average diameter were 98.32%,88.40% and 96.23%,respectively.Root surface area genetic model4MG-EEA,major gene heritability was 94.99%;there were two traits in the mixed model of major gene plus polygene.The genetic model of thousand grains weight was MX1-A-AI,and the genetic model of root volume was MX2-AE-A.The heritability of main gene was50.14% and 58.62%,respectively,and the heritability of polygene was 49.75% and 40.75%,respectively.The effective tiller number,flag leaf width,grain area,grain length and grain width were polygenic inheritance model PG-AI,and the polygenic heritability was 12.38%,25.60%,98.00%,77.76% and 93.99%,respectively.For traits with high polygenic heritability,the influence of minor polygenes should be paid attention to in breeding,and minor polygenes should be accumulated by recurrent selection breeding or backcross breeding.The traits with high heritability of major genes are less affected by the environment,and single plant selection can be carried out in early generations during breeding. |
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