Abstract:

In this paper, the chromosome number and karyotype of jackfruit was studied after detaching the cell wall and treated with low osmotic solution, and the effects of different pretreatments were also investigated. The results showed that the optimum pretreatment chemical was the mixture of 0.2% colchicine and 0.002 mol/L 8-Hydroxyquinoline (1:1), with the pretreatment time for 3 hours. The karyotype analysis showed that jackfruit was diploid (2n=2x=56). The ratio of the longest chromosome to the shortest one is 2.08:1, and the arm ration of 3.5% chromosomes is over 2, so that the karyotype formula of jackfruit is 2n=2M+50m (2SAT) +4sm, belonging to 2A karyotype. It is the first report that the B Chromosome may be in jackfruit.