Evaluation of chromosome diversity of Elymus nutans on the Qinghai-Tibet plateau by FISH

Elymus nutans Griseb. is an important herbage for forage and ecological restoration in the Qinghai-Tibet Plateau (QTP). It is widely distributed in different habitats of the QTP and has been reported to have high genetic diversity in protein, morphology and DNA sequence. The main objective of our investigation has been to obtain some knowledge of E. nutans chromosome genetic diversity. In this study, the TE probe S5 and tandem repeat probe AAG combined with sequential GISH were able to successfully distinguish different subgenomes and chromosomes in 7 E. nutans accessions from major global distribution sites. On this basis, a total of 123 individuals from four representative populations of E. nutans in the QTP were hybridised. The results of the experiment showed that four types of reciprocal translocations between subgenomes were observed in the four wild populations, and the translocation chromosomes, frequency, and heterozygosis were different in each population. The distribution and quantity of S5 and AAG signals also varied within and among the four populations. The results indicated that E. nutans had high genetic diversity at the chromosome level both within and among populations, and it was speculated that non-homologous recombination was one of the reasons for the high genetic diversity. These results provide important theoretical guidance for the collection, protection, and evaluation of E. nutans.