杂交狼尾草和桂牧1号杂交象草的核型分析

摘要

The chromosome number and karyotype of P.americanum × P.purpureum and (P.arericanum× P.purpureum) × P.purpureur schum.cv.Guimu 1 was analyzed by the root tip squash method to provide the theoretical basis for diversity protection,utilization and genetic breeding of Pennisetum germplasm resources.Results:The basic chromosome number,ploidy and chromosome number of P.americanum × P.purpureum and (P.americanum × P.purpureum) P.purpureum schum.cv.Guimu 1 both are 7,triploid and 21 respectively.The karyotype formulas and relative chromosome length of P.americanum×P.purpureum are 2n=3x=21=18 m (6SAT) + 3 sm and 6S+ 3 M1+6 M2+6 L separately and there is a trabant on the chromosome of Group 1 and Group 5.The karyotype formulas and relative chromosome length of (P.americanum P.purpureum) P.purpureum schum.cv.Guimu 1 are 2n=3x=21=3 m+18sm and 6S+6M1+3M2+6L respectively and there is no a trabant on their chromosomes.The karyotype asymmetrical coefficient and karyotype of P.americanum × P.purpureum and (P.americanum P.purpureum) P.purpureum schum.cv.Guimu 1 is 60.79％00 and 1B type,and 65.06％ and 2B type separately.The evolution degree of (P.americanum P.purpureum)P.purpureum schum.cv.Guimu 1 is higher than P.americanum× P.purpureum%为狼尾草属种质资源的多样性保护、利用及遗传育种研究提供理论依据,采用常规压片法对杂交狼尾草和桂牧1号杂交象草的染色体数目及核型进行分析.结果表明:2种牧草的染色体基数为x=7,均为3倍体,染色体数目为2n=21条.杂交狼尾草的核型公式2n=3x=21=18m(6SAT) +3sm,染色体相对长度组成I.R.L=6S+3M1+6M2+6L,第1组和第5组染色体含有随体;桂牧1号杂交象草核型公式2n=3x=21=3m+18sm,染色体相对长组成I.R.L=6S+6M1+3M2+6L,未发现随体.杂交狼尾草和桂牧1号杂交象草核型不对称系数分别为60.79％和65.06％,分别属于1B型和2B型,桂牧1号杂交象草的进化程度高于杂交狼尾草.