Abstract:

In this paper, the polyp loidswere induced by low concentration of colchicin and oryzalin solution at early develop ing embryo in order to research and produce a new sort of germplasm of autotetrap loid in Dendrobium hybrida orchilds. During the process, the cross-pollinated seeds in the same plant were utilized as materials to obtain the PLBs through seed non-symbiotic germination and induction which app lied in the process of tissue culture. The results revealed that the rate of tetraploid was over 90% when treated with
0.01% colchicine and 5 mg·L ^{- 1} oryzalin during 8 - 10 days. Moreover mosaic was not found in the doubling materials in the whole experiment. Compared with diploid, the tetraploid plantlets have always been more stout, the leaf are dark green and wide-thick

Key words: Dendrobium hybrida, autotetrap loid, seed, protocorm-like body ( PLB ), early developing embryo, oryzalin