Variation Analysis Of Related Characters On Degraded Population Of Agropyron Cristatum ×A.desertorum Cv.Hycrest-Mengnong

The degraded population of theA.cristatum×A.desertorum cv.Hycrest-Mengnong was used as material,field observation and laboratory analysis were used to determine 15 agronomic traits for two years,and SSR markers were used to identify and evaluate the variation and genetic differentiation of the related traits in the degraded population.The aim is to provide basis for genetic improvement and new variety breeding of Agropyron and other grasses.The main results were as follows:1.The original population of the A.cristatum ×A.desertorum cv.Hycrest-Mengnong degraded obviously,and the 15 characters were different in variation degree,the coefficient of variation was 25.49%on average.The variation of the first inter node length,above ground biomass and plant height was obvious.The forage yield of the highest plant was much higher than that of the control.The difference between the highest plant and the shortest plant was more than 50 cm.The variation coefficients of leaf length,leaf width and first flag leaf length were 31.66%,28.2%and 33.53%,respectively,and the leaf chlorophyll content of narrow-leaf material was significantly higher than that of wide-ear material,the difference was 30.07.The panicle characters were stable and the difference was not significant.2.There were some correlations among the characters,among which the plant height was positively correlated with the leaf length,leaf width and above ground biomass,positively correlated with the first flag leaf length,and negatively correlated with the spikelet width and the number of spikelets per spikelet;The above-ground biomass was positively correlated with the length of the first inter node,and negatively correlated with the width of the spike,and positively correlated with all the traits of the panicle,but negatively correlated with the length of the stem and inter node of the plant cluster.The first five principal components covered 79.01%of the total variation,and the variation of the traits were further subdivided into plant type factor,leaf type factor,spike type factor and yield factor.3.On the whole,the degree of variation of traits related to vegetative growth was higher,but the degree of variation of traits related to reproductive growth was lower.The plant height,leaf length,leaf width and above ground biomass were the main target traits to improve the population,and the potential of regeneration and rejuvenation was greater.In the process of population genetic improvement or purification and rejuvenation,the plant type,leaf type,spike type,forage yield and seed yield should be considered,such as the goal is to increase forage yield,it is better to select the materials with high plant height,long first inter node,long leaf or long leaf,and to eliminate the materials with long inter node and big cluster when breeding improved varieties.4.A total of 155 SSR bands were amplified from 21 pairs of Primers,and an average of 7 bands were amplified from each pair of primers.The polymorphism bands accounted for 81.8%.The genetic diversity of the original degenerated population of the wheatgrass is rich and the genetic differentiation is obvious,the genetic diversity index is 0.4673,the Shannon index is 0.6576,the genetic differentiation coefficient is 0.4312,and the gene flow is 0.9093.5.According to the Coefficient of genetic similarity,Principal Component Analysis(PCA)and cluster analysis(CA)were conducted on the individual plants of the tested materials.It was found that the genetic differentiation among the individual plants of the tested materials was relatively high.The CA analysis classified the tested materials into two categories,one containing 50 plants,the other group contained 40 plants.