Studies On Genetic Diversity Of Two Species Of Elymus Germplasm Resources

This paper mainly studied the characteristics of distribution and adaptation to the environment of Elymus sibiricus and Elymus nutans from different geographic regions to reveal genetic differences,genetic variation and genetic relationship among the experimental materials,using thirty-one Elymus sibiricus and nineteen Elymus nutans from 38 counties or cities of China's eleven provinces (or autonomous regions) as the subjects and phenotypic traits, main agronomic traits and ISSR molecular markers as the contents of study.The main results were as follows:1. Phenotypic research showed that there were significant differences between species and intraspecies and differences between species are more than that of intraspecies,displayed plentiful phenotypic diversity.Based on the principal component analysisi,there were twelve main traits that determined phenotypic variation of Elymus sibiricus.In order of effects,they were plant height, spikelet number, distance between flag leaf and ear base,ear length,awn length of lemma,flag leaf length, width of the second leaf from bottom, length of palea, length of second leaf from bottom, length of the first internode under spike, length of first glume, flag leaf width. there were eleven main traits that determined phenotypic variation of Elymus nutans.The influences decreased in the order of plant height, spikelet number, ear width, length of palea, length of lemma, length of the first internode under spike, ear length, awn length of lemma, flag leaf width, distance between flag leaf and ear base, flag leaf length. Nine of these shapes were the main traits p that determined henotypic variation of Elymus sibiricus and Elymus nutans.The cluster analysis showed that the same species materials clustered together,clusters of intraspecies were being affected by altitude and latitude,the similar morphological materials get together first,and the materials from same or similar geographical origins could partially get together centrally.2. The comparison of main agronomic traits indicatesed that the differences of growth period of Elymus sibiricus when greater than that of Elymus nutans. The growth period of experimental materials from regions of low altitudes and high latitudes are obviously longer than those from high altitudes and low latitudes regions. The respective maximum extent of plant height for Elymus sibiricus and Elymus nutans are from Tillering date to Booting date and from Tillering date to Flowering date. Elymus sibiricus and Elymus nutans had the same period of greatest change of leaf area index, which was from Tillering date to Jointing date. In full ripening date, the plant height of Elymus sibiricus from regions of high altitudes was taller than those from low altitudes regions.compared wih Elymus nutans, the plant height from regions of high latitudes was taller than those from low latitudes regions, and the leaf area of Elymus sibiricus from high latitude regions was greater than those from low latitude regions, and the leaf area of Elymus nutans from high altitudes regions was greater than those from low altitudes regions. On the whole, the fresh/dry ratio of per plant of Elymus nutans was greater than that of Elymus sibiricus, ES018 and EN014 possessed abundant nutritive value, had greater fresh/ dry ratio of per plant than other materials. Elymus sibiricus from high latitudes had greater single panicle weight. Compared comprehensively, ES010,ES011,ES014,ES021,ES024,EN010,EN01,EN015 had the priority to utilize,because of better performance of the dry weight ratio of stem/spike, tiller number of per plant and single panicle weight.Elymus sibiricus mainly were late maturing materials and Elymus nutans mainly were early materials, the late maturing materials characterized by lower plate, greater leaf area and more tiller number, compared with the early materials, which marked by taller plate, smaller leaf area and fewer tiller number.3. The optimization reaction system of Elymus sibiricus and Elymus nutans was 25μL. It included 2.5μL 10×buffer(except Mg²⁺), 1.0 U TapDNA polymerase, 2.0 mmol/L Mg²⁺, 30～120 ng template DNA,0.25 mmol/L dNTP and 0.25μmol/L primer.The reaction program was devised for 2 min at 94℃in the first circle,1 min at 94℃for 41 cycles, 51℃for 1 min (depended on different primer), 72℃for 1.5 min, and 72℃for 10 min for extending,stored at 4℃.The experimental materials had rich genetic diversity.there were much more genentic diversity among materials.12 ISSR primers were utilized for the amplication reaction of 31 Elymus sibiricus and 19 Elymus nutans,A total of 111 bands were obtained by amplication of the polymorphic primers of 50 experimental materials,.in which 107 bands were found to be polymorphic,The percentage of polymorphic bands was 96.40%.The effective number of alleles,the index of Nei's genetical diversity and Shannon's information index of 50 experimental materials were 1.552,0.304 and 0.456, respectively.The percentage of polymorphic bands,the effective number of alleles,index of Nei's genetical diversity and Shannon's information index of 31 Elymus sibiricus were 92.79%,1.442,0.273,0.424,compared with 84.68%,1.433,0.263,0.403 of 19 Elymus nutans,and the genentic diversity in Elymus sibiricus were greater than Elymus nutans.ISSR marker could distinguish 50 different experimental materials from each other,the materials of same species could get together first, cluster analysis in species were correlated with the distribution of materials, influenced by altitude and latitude there were inter-cross among different origin of same species.