Biosystematic studies on Hystrix longearistata from Japan and Hystrix duthiei from China (Poaceae: Triticeae)
ZHOU Yong Hong YANG Jun Liang YAN Ji ZHENG You Liang (Triticeae Research Institute, Sichuan Agricultural University, Dujiangyan 611830, Sichuan)
Morphological comparison, cytogenetic study and fertility analysis of Hystrix duthiei (2n=28) from China, Hystrix longearistata (2n=28) from Japan and their artificial hybrids were carried out. Morphologically H. duthiei was similar to H. longearistata. H. longearistata had longer lemma awn,wider leaf and 2～3 florets per spikelet, while H. duthiei had 1～2 florets per spikelet. These two taxa can be easily crossed. F 1 hybrids showed very high degree of bivalent pairing (13～14 bivalents) at the metaphase Ⅰ of meiosis. No multivalents were found. The fertility of pollen and seed set of the parents were normal, while the F 1 hybrids were of only partial fertility. H. longearistata was closely related to H. duthiei. They should be included in the same species. Because of the differences of their distributions and habitats, some morphological divergency and a little sterility barrier have had appeared between them. It is reasonable to treat Hystrix longearistata as a subspecies of Hystrix duthiei.