Karyotype analysis of Pennisetum purpureum×P. americanum cv. Reyan No.4 and P. purpureum cv. Guiminyin

The present study investigated the chromosome number and karyotype of Pennisetum purpureum×P. americanum cv. Reyan No.4 and P. purpureum cv. Gui minyin using the conventional compression method to provide theory basis of Pennisetum germplasm resources diversity protection and genetic breeding research. The results showed that their basic chromosome number was 7. Reyan No.4 was triploid and the chromosome number was 21, the karyotype formula was 2n=3x=21=21m (3SAT), the formula of chromosome relative length was I.R.L=9S+3M1+3M2+6L, three of chromosomes have trabant. Gui minyin was tetraploid and the chromosome number was 28, the karyotype formula was 2n=4x=28=18m (2SAT) +10sm (2SAT), the formula of chromosome relative length was I.R.L=10S+6M1+4M2+8L, four of chromosomes have trabant. For Reyan No.4 and Gui minyin, index of the karyotypic asymmetry was 60.15% and 62.19%, the karyotype was 1B type and 1C type, respectively. The results indicated that their karyotype belong to primitive types .