| There are about four species of Zizania Linnaeus plants in the world,namely Zizania aquatica,Zizania latifolia,Zizania palastris,and Texas Zizania texana.Zizania latifolia distributed in China is a kind of perennial water plant,which not only has rich food value,medicinal value,ecological value and ornamental value,but also is one of the closely related genera of rice.It shares the similar environmental conditions and growth cycle with rice.Wild Zizania latifolia has strong resistance to rice blast and blight.It is a natural carrier of fine trait control genes in rice breeding and is considered by many breeders as an important source of excellent outer edge genes in rice breeding.Therefore,the investigation of wild germplasm resources and the study of its genetic diversity are of great significance.The homologous sequence(RGA)selected in this paper as a new type of molecular marker has been found to have extensive polymorphism in many species.There are great potential applications in genetic diversity,clustering and genetic structure analysis among genomes.According to the reported DNA molecular markers for rice blast resistance,10 pairs of primers with more amplified bands,more polymorphism,and better repeatability were screened and optimized.Genetic diversity and genetic structure were analyzed at the molecular level in 381 samples from 25 wild population.Through the continuous improvement of the basic information materials of wild rice resources in China,it provides corresponding theoretical basis and reference basis for the protection and utilization of wild rice germplasm resources in China.The main findings are as follows:(1)Genetic polymorphism analysis: The results of the RGA-PCR experiment showed that polymorphism was abundant,with a total of 162 clear and stable strips,of which the polymorphism strips had 114 and the number of 10 primer amplification strips was between 7~24,each pair of primers amplified an average of 16.2 fragment bands,and the amplified DNA fragments were concentrated between 200-1800b;At the species level,the percentage of polymorphism sites is as high as 74.20 %,and thedifference between the population groups is quite large.The average percentage of polymorphism sites in 25 wild populations in the country is only 19.65 %.(2)At the level of genetic diversity,China's wild Zizania latifolia ‘s Na = 1.74,Ne= 1.37,He = 0.266,and I = 0.360.The AMOVE analysis showed that the ratio of genetic variation between populations was 50.25 %.The ratio of genetic variation within the population is 49.75 %,which is consistent with POPGEN's analysis results,indicating that the genetic variation between populations is higher than within the population.Genetic structure analysis shows that the genetic diversity(Ht)among the population is 0.155,the genetic diversity(Hs)within the population is 0.074,the genetic differentiation coefficient(Gst)within the population is 0.520,and the gene flow(Nm)between the population is 0.463;It is indicated that genetic drift has played a role in the differentiation of wild birds in China.(3)The results of clustering,genetic distance,and geographical distance show that the population groups between regions are obviously gathered together,and the four major regions are obviously separated in position,forming a clear genetic structure,and the principal component is consistent with the results of the phylogenetic tree.,The 25 colonies in the country are obviously grouped into two groups according to the North and South,and have a common ancestor.The correlation showed that the R value was0.8769,and the significant level P= 0.001 <0.050 was detected by Mantel,indicating that the genetic distance and geographical distance between wild birds were significantly positive.The results of this study provide some basis for genetic diversity and evolution analysis,exploitation and utilization of gene resources and protection of germplasm resources. |
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