| As the most important group in tribe Triticeae of the grass family (Poaceae), Elymus L. is not only an important gene pool for crops, such as wheat and barley, but also an important part of fine forages. However, the genome constitution of some species of Elymus is still unknown; the phylogenetic relationships are not systematically revealed among Elymus. Thus, the majority of species in Elymus are not better utilized in practise. In order to provide certain data for establishing an accurate classification system for Elymus L., specific markers were used to verify and test the genome constitution and genetic relationship among Elymus species based on morphological markersand SRAP and ISSR markers in this study. The main research results were showed as follows:1. STS, RAPD and SCAR markers were used to evaluate that whether the specific markers of St, H and Y genome were feasible in testing the genome constitution of Elymus species and to reveal the genome constitution of Elymus species. The results showed that:(1) the specific markers of St, H and Y genome were detected in all of the materials. The results of makers in the same genome showed high level of consistency which showed that all of the specific markers had a good stability. STS markers, transformed from RAPD had more advantage in observation and study.(2) Authentication of the specific markers of three genomes, showed that the specific markers of St had a stronger specificity rather than specific markers of H or Y.(3) The results of this study showed five species of Elymus whose genome constitution were unknown all had the St genome. Maybe the Y or H was also a part of these species, but it needed to be studied further.2. Based on53morphological indexes, the genetic relationship was studied among11species in Elymus. The results showed that:(1)11species were clustered into three groups. The first group comprised E.atratus, E.nutans, E.sibiricus, E.breviaristatus and E.submuticus; the second group comprised E.atratus, E.dahuricus, E.cylindricus, E.tangutorum, E.excelsus and E.dahuricus var. violeus; The third group just includedE.purpuraristus.(2) Differentiation was universal within species contributed to two accessions of E. atratus were clustered into two groups and the classification of species existed crossoverin groups.(3)85.445percent of information was revealedfrom the first9principal components.20morphological indexes which had a large variation were screened out from the9principal components. Half of20indexes came from lower glume and lemma, which maybe was significant for studying genetic relationship among Elymus L.3. Based on the data of SRAP and ISSR markers, clustering trees were built to study the genetic relationship among11species of Elymus L. The results showed that:(1) A total of808bands were detected in30accessions used by21pairs of SRAP primers combination with87.50%of polymorphic bands.267bands were detected by 15ISSR primers with89.51%of polymorphic bands. Both of the two markers revealed rich variation in Elymus species, thus SRAP and ISSR were suitable for the study of genetic relationship among Elymus L.(2) Though the range of Jaccard’s genetic similarity coefficient of ISSR was wider than SRAP, the Mantel test showed a significant correlation between them (r=0.967, p=0.001).(3) Combined with the result of two markers,11species were clustered into three groups. The first group comprised two accessions of E.sibiricus; The second group comprised four species, such as E.nutans, E.breviaristatus, E.submuticus and E.atratus, from which E.breviaristatus and E.submuticus reflected closer genetic relationship; The third group comprised E.dahuricus, E.cylindricus, E.tangutorum, E.excelsus, E.dahuricus var. violeus and E.purpuraristus, from which the classification of species existed usually crossover in groups. |
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