Genetic Diversity Of Permanent Stable Small Populations Of Festuca Rubra L. And Trifolium Repens L.

Gramineous pasture and leguminous grass are important plants in artificial grassland in karst area.The Zhuopu demonstration farm in the Guizhou Plateau Grassland Experimental Station is a typical karst area.After more than 30 years of research,the productivity and stability of the Festuca rubra L.and Trifolium repens L.in the mixed grassland community are the highest.The results of field observations showed that the small populations of Festuca rubra had higher similarity and less morphological differences.The small population of Trifolium repens has been mutated,and the leaves have different shades and irregular shapes.RAPD technology is a molecular technique for polymorphism analysis with high sensitivity,high efficiency and easy detection.Based on the advantages of genetic diversity in RAPD technology,this paper studied the genetic diversity of the stable population of Festuca rubra and Trifolium repens in Zhuopu demonstration farm.In this experiment,30 primers were selected,and the Festuca rubra and Trifolium repens were screened respectively,and the selected primers were subjected to RAPD amplification.The statistical results showed that the Pr population,the Pz population,the Pm population and the Tr population obtained 7,7,7 and 8 specific primers,respectively.The total number of amplified bands was 50,56,70 and 55,respectively.The polymorphic bands were 19,44,53 and 46,respectively.The percentage of polymorphism was 38%,78.57%,75.71% and 83.64%,respectively.The artificially isolated small population of Festuca rubra.has low genetic diversity,its stability is not related to genetic diversity,and its genetic diversity and morphological diversity are similar.Although the genetic diversity of artificially planted small populations of Festuca rubra is low,it is even more Stable and lasting.The results of polymorphism percentage were Pz population > Pm population > Pr population,and the genetic diversity of wild Festuca rubra was richer than that of artificially planted small populations.The artificially isolated Trifolium repens population is rich in genetic diversity,and the stability population is positively correlated with genetic diversity.Genetic diversity has a certain relationship with morphological changes.The genetic diversity of Trifolium repens is higher than that of Festuca rubra,which may be related to plant characteristics and population structure.The phylogenetic tree was constructed using UPGMA to explore the genetic relationship within the population.The analysis results showed that the minimum genetic distances of Pr population,Pz population,Pm population and Tr population were 0,0.15,0 and 0.12,respectively.The maximum genetic distances were 0.6,0.76,0.78,and 0.54,respectively.The average genetic distances were 0.28,0.33,0.26,and 0.32,respectively.Geographical barriers are the main cause of genetic differences,and genetic variation of Festuca rubra is affected by geographic distribution.The genetic relationship between the materials of the artificial small population are relatively close.and the wild population materials are far away from each other,which may be limited by the distribution range and environmental conditions.The results enriched the theory of population and community stability and laid the foundation for the study of the molecular mechanism of grassland community stability in karst areas.