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Discussion

K. gobicola and K. zhaosuensis are new species which were found in west China in recent years. Their genomes were not analysed. Their karyotypes showed that they possess a set of long chromosomes, which can be distinguished clearly from H, S, and Y genomes. The fourth and sixth chromosomes of karyotypes were satellite chromosomes which were similiar to those of P genome of Agropyron (Yen et al. 1989, 1990). According to the karyotypes, Yen and J. L. Yang (1989, 1990) infer that K. gobicola and K. zhaosuensis have the P genome and two sets of other genomes.

R. tsukushiensis has the S, H and Y genomes (Sakamoto 1964, Dewey 1984, Lu et al. 1990). The frequencies of 11.56 and 11.73 bivalents per cell were found in the hybrids of K. gobicola and K. zhaosuensis crossed with R. tsukushiensis respectively. The results indicated that K. gobicola and K. zhaosuensis share two sets of genomes of R. tsukushiensis and the two genomes of K. gobicola and K.
zhaosuensis have high homology with the two genomes of R. tsukushiensis.

Chromosome bridges at anaphase I and II were found in meiosis of K.
zhaosuensis x R. tsukushiensis. It showed that paracentric inversion probably occurred between the genomes of K. zhaosuensis and R. tsukushiensis.


Reference

Dewey DR (1984) The genomic system of classification as a guide to intergeneric hybridization with perennial Triticeae. In: Gene manipulation in plant improvement. Ed: Gustafson JP Pleum Press New York, pp 209-279.

Lu BR, Yen C and Yang JL (1990) Cytological and morphological studies of
Agropyron tsukushiense var. transiens of Japan, Roegneria kamoji of China and their artificial hybrids. Acta Bot. Yunnanica 13 (3): 237-246.

Ohwi J (1965) Flora of Japan. Smithsonian Institution, Washington.

Sakamoto S (1964) Cytogenetic studies in the tribe Triticeae I: A polyhaploid plant of Agropyron tsukashiensis var. transiens Ohwi found in a state of nature. Jpn J Genet 39: 393-400

Sun GL, Yen C and Yang JL (1990) Observations on chromosome numbers of perennial species of Triticeae from Xinjiang. Guiliaia 10: 143-148.

Sun GL, Yen C and Yang JL (1993) Studies on karyotypes of 2 species in
Kengyilia and 3 species in Roegneria. Acta Phytotaxonomica Sinica 31: 560-564.

Yang JL, Yen C and Baum BR (1992) Kengyilia: synopsis and key to species. Hereditas 116: 25-28.

Yan J (Yen C), and Yang JL (1990) Kengyilia, a new genus of tribe Triticeae of
Gramineae from China. J Sichuan Agric Univ 8: 75-76.

Yen C and Yang JL (1990) Kengyilia gobicola, a new taxon from west China. Can J Bot 68: 1894-1897.

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