Karyotype Analysis of Different Varieties of Cosmos sulphureus
The chromosome number was observed and karyological analyses on eight cultivars of Cosmos sulphureus were carried out with conventional pressed slice method.These provided necessary evidence for the resource collection,origin analysis and cultivation of good varieties for Cosmos sulphureus.The result:The chromosome number of Cosmos sulphureus for the test was stable,each cultivars of Cosmos sulphureus was mostly 2n=24;The karyotype types were 3B and 2A;The ratio between the longest chromosome and the shortest chromosome was from 1.37 to 2.30.The percentage of chromosomes of arm ratio over 2∶1 was 25%～58.33%;The karyotype asymmetry indexes(As.K)of eight cultivars were from 60.38%to 67.10%,which implied the karyotype of Cosmos sulphureuswas morer evolution,the'Youya'karyotype of which was the most evolutive.
万方数据
