The Karyotype Analysis Of 12 Roegneria Species And The Study Of Some Natural Hybrids Of Kengyilia Rigidula

Roegneria C. Koch, Elymus L. and Kengyilia Yen et Yang are important perennial genera in the tribe Triticeae (Poaceae). Many species are fine herbages. Some species have characters of resistance to disease, insect resistance and tress tolerance, which are precious gennplasm resources in crop breeding. However, definitions of the three genera and their precise taxonomic ranks have been under discussion. The aims of the present paper are: (a) to discuss the relationships among the 12 tetraploid species in Roegneria by the karyotype analysis; (b) to study the possible parents of ZYNH 5, the natural hybrid of Kengyilia rigidula in Ruoergai, Sichuan, by the meiosis; (c) to evaluate the genomic constitutions and the possible parents of the four natural hybrids of Kengyilia rigidula in Xiahe and Luqu, Gansu, by the means of genome specific RAPD. The main results were as follows:1. Karyotypes of 12 tetraploid species in Roegneria have been studied. The karyotype formulae are as follows: R. aristiglumis Keng et S. L. Chen, 2n=4x=28=22m+6sm(2SAT); R. breviglumis Keng, 2n=4x=28=20m(2SAT)+8sm; R. hongyuanensis L. B. Cai, 2n=4x= 28=22m+6sm(2SAT); R. shandongensis (B. Salomon) J. L. Yang, Y. H. Zhou et Yen, 2n=4x=28=24m(2SAT)+4sm; R. tenuispica J. L. Yang et Y. H. Zhou, 2n=4x=28=22m+ 6sm(2SAT); R. purpurascens Keng, 2n=4x=28=24m(2SAT)+4sm; R. anthosachnoides Keng, 2n=4x=28=24m(2SAT)+4sm; R. stricta Keng, 2n=4x=28=22m+6sm(2SAT); R. parvigluma Keng, 2n=4x=28=22m+6sm(4SAT); R. gracilis L. B. Cai, 2n=4x=28=24m (2SAT)+4sm; R. multiculmis Kitagawa var. pubiflora Keng, 2n=4x=28=20m(2SAT)+8sm; R. dura (Keng) Keng var. variiglumis Keng, 2n=4x=28=24m+4sm(2SAT). The karyotypes of R. aristiglumis, R. stricta, R. parvigluma, R. gracilis, R. multiculmis var. pubiflora and R.