Identification of Ploidy Variation of Ponkan Embryo Rescue Plants

Abstract

China has abundant of local citrus resources, which had many seeds. The Seedless is the aim of the local citrus breeding. Triploid citurs resources usually obtained by crosssing breeding between the diploid and tetraploid plants. However, the resources of tetraploid citrus are limited. It has been reported that the hybrid between diploid and diploid plants can produce triploid citrus, which not only saves the breeding time, but also shortens the breeding cycles. In this project, flow cytometry detection assisted by embryo rescue system and SSR identification technology were used to improve the probability of obtaining polyploidy from the hybrid offspring, and provide technical support for obtaining polyploidy from large-scale hybridization between diploid and diploid. plants. Three diploid pollen cultivars were crossbred with Hunan local cultivar 8306, immature seeds were collected for embryo rescue to obtain regenerative plants, plant ploidy was detected by flow cytometry and stoma electron microscope, and offspring genotypes were identified by SSR. After 100 d hybrid between three diploid pollens and Ponkan 8 306, 405 plants were obtained by embryo rescue technique. And 70 plants survived in the greenhouse after transplantation. Through flow cytometry instrument and stomatal electron microscope inspection, the results showed that SSR analysis validated that there are 13 polyploid plants, including 1 tetraploid plant and 12 triploid plants. The ratio of polyploidy was 18.57%. This study is obtained triploid and tetraploid plants by Ponkan embryo rescue from diploid interspecific hybridization. In this study, the embryo rescue technology system and the early identification system for polyploid hybridization were established, and a lot of new polyploid germplasm were obtained.