Production Of Somatic Hybrids Between Two Species And Analysis Of Tuberization In Potato

Potato (Solanum tuberosum L.) is the fourth largest food crop in the world, and its wild species is rich in resistant resources and special characters. However, there is cross-incompatibility between the wild species and the cultivated species as the result of the difference in Endosperm Balance Number (EBN). Solanum etuberosum is one of the wild potato species which is naturally lack of tubers. It has a lot of biological and non biological resistance, but it is difficult to succeed with the hybrid culture.The tuber, of which the formation is effected by a variety of facts, is the important economic organs and reproductive organs of the potato. In this study, we want to get some somatic cell hybrids between the S. etuberosum and the other three diploid species which are significant different in tuber ability, at last, the genetic characteristics of tuber in S. etuberosum could be analyzed. At the same time, the rich resistance genes in the S. etuberosum would be transferred into the somatic hybrids so as to produce new ermplasm resources with some resistance. The results obtained are as follows:1. Electrofusion was used to obtain somatic hybrids between S. etuberosum and three diploid, tuber bearing Solanum clones:AC 142、XD-3、USW4.128 regenerated plants of the two fusion combinations were successfully obtained from etbl+AC142 and etb1+XD-3. Then, regenerated plants were identified for somatic hybrids by SSR primer. The results showed that the 93 plants were somatic hybrids in the etbl+AC 142 fusion combination of the 95 regenerated plants, and the hybrid plants rate was as high as 97.90%; the 22 plants were somatic hybrids in etbl+XD-3 fusion combination of the 35 regenerated plants, and the hybrid plants was 66.67%. Somatic hybrids ploidy was Analyzed by flow cytometry. The results showed that hexaploid is the main ploidy in somatic hybrids with other different ploidy distributed from triploid to octoploid, in addition, there were a small number of mixoploid plants.2. The agronomic traits survey results of the somatic hybrids indicated that the growth potentia of the tetraploid were better than the hexaploid, and they all were better than other ploidy plants. The plant morphology of the most somatic hybrids was intermediate between the two fusion parents.Most of the tetraploid and the hexaploid somatic hybrids were normally flowered, and the pollen viability was distributed approximately from 0 to 36.23%. Moreover, Late blight races 16-2 and 3928A were inoculated in vitro in compound leaves of the somatic hybrids so as to identify the resistance to late blight of these somatic hybrids. The results showed that all somatic hybrids which were detected were susceptible. The tuber characteristic analysis of the somatic hybrids showed that most of somatic hybrids could form tuber. However, there were significant differences in tubers numbers and tubers weight between the plants with different ploidy and even with the same ploidy. They laid the foundation for the next research about the potato tuber development.