杂交狼尾草和桂牧1号杂交象草的核型分析

Karyotype Analysis of Pennisetum americanum×Pennisetum purpureum and(Pennisetum americanum×Pennisetum purpureum)×Pennisetum purpureum schum. cv. Guimu

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。

The chromosome number and karyotype of P.americanum × P.purpureum and（P.americanum×P.purpureum）×P.purpureum 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.purpureumare 2n=3x=21=18m（6SAT）＋ 3sm and 6S＋3 M1＋6 M2＋6Lseparately and there is a trabant on the chromosome of Group 1and Group 5.The karyotype formulas and relative chromosome length of（P.americanum P.purpureum）P.purpureum schum.cv.Guimu 1are 2n=3x=21=3m＋18sm and 6S＋6M1＋3M2＋6Lrespectively and there is no a trabant on their chromosomes.The karyotype asymmetrical coefficient and karyotype of P.americanum×P.purpureumand（P.americanum P.purpureum）P.purpureumschum.cv.Guimu 1is 60.79%and 1B type,and 65.06% and 2Btype separately.The evolution degree of（P.americanum P.purpureum）P.purpureumschum.cv.Guimu 1is higher than P.americanum×P.purpureum