| Most of potato cultivars are tetraploid with narrow genetic base. While the wild potato species enrich with germplasm resources and advantageous genetic characteristics. Most of wild potato specises are diploid, due to the variety of the ploidy resulting in difficult to cross with potato cultivars, so the germplasm resources and advantageous genetic characteristics of wild potatoes can not be used.In this paper we used wild diploid potato Solanum chacoense, the homozygous after ten generation of S. chacoense, double haploid potato DM and wild diploid potato S. microdontum. Colchicine were used to treat the diploid potato axillary bud and to induce tetraploid potatoes. Cut a small piece (approximately 2 mm2) of leaves which had been treated by colchicines to produce the nucleus slices. For rapid identifying the ploidy of the material after induction and screening polyploidy,5S rDNA was used as probes and performed fluorescence in situ hybridization (FISH). The results showed that there was one and two signals located on diploid and tetraploid potatoes respectively.926 plants had been treated and screened 3 tetraploid,4 chimeras include the diploid and tetraploid ploidy, also a chimera include diploid tetraploid and octaploid. Based on the analysis and comparison of flow cytometry analysis and chromosomes counting for the tetraploid and chimera which had been screened, confirmed the material of the authenticity and reliability of our screening method. The efficiency is best when the concentration of colchicines is 0.05% and soak the axillary bud 10 days during the different colchicine concentration, the induction rate was 3.3%.In this paper we found a best induced condition for artificially synthesized polyploid induction of wild diploid, obtain some artificially synthesized tetraploid potatoes; found a new fast and accurate method for identify the ploidy. Proved a new technology and material for speeding up the potato polyploidy breeding and using of wild germplasm resources. |
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