中文摘要：

对红原县引种早熟与晚熟猫尾草（PhleumpratenseL．）细胞染色体进行核型分析．研究表明，早熟猫尾草染色体数为2n=28，染色体的核型为K（2n）-2n-4x=28-22m＋4sm（SAT）＋2st（SAT），其中第5、11对染色体为近中部着丝粒染色体，第8对染色体为亚端部着丝粒染色体，其余各对染色体为中部着丝粒染色体，第8对染色体携带随体；晚熟猫尾草染色体数为2n=42，染色体的核型为K（2n）-2n=6x=42-2M＋24m＋14sm＋2sm（SAT），其中第3、4、6、11、12、13、14、20对染色体为近中部着丝粒染色体，第18对染色体为正中部着丝粒染色体，第22号为B染色体，其余各对染色体为中部着丝粒染色体，第11对染色体携带随体．早熟与晚熟猫尾草都属2A核型．

英文摘要：

The karyotypes of metaphase chromosomes of introduction prematurity and latematurity Phleum pratense L. were analysed in Hongyuan County, China. The result showed that chromosome number of prematurity Phleum pratense L. was 2n=28. The karyotype of prematurity Phleum pratense L. was K（2n） = 4x=28=22m＋4sm（SAT）d-2st（SAT）, the fifth, eleventh pairs were subtelocentric chromosomes, the eighth pairs were submetacentric chromosomes, and the rest pairs were metacentric chromosomes, the eighth pairs chromosomes with satellite were observed~ chromosome number of late- maturity Phleum pratense L. was 2n = 42. The karyotype of prematurity Phleum pratense L. was K （2n） =6x=42=2M＋24m ]-14sm＋2sm（SAT） ,the third, fourth, sixth, eleventh, twelfth, thirteenth, fourteenth, twentieth pairs were subtelocentric chromosomes, the eighteenth pairs were median metacentric chromosomes, twenty second chromosome was B chromosome, and the rest pairs are metacentric chromosomes, the eleventh pairs chromosomes with satellite were observed. Karyotypes of prematurity and latematurity Phleum pratense L. belong to Stebbins＇s 2A type.