Homozygous Line And Genetic Transformation System Construction Of Hongkong Kumquat

Citrus as one of the main fruit crops in the world, was widely grown and consumed. Fortunella belonging to citrus has a long cultivation history in the original centre China, and it is one of the important germplasm resources of citrus. The Hong Kong kumquat(Fortunella hindsii Swingle) is an evergreen fruit tree of Rutaceae family. It can serve as the material of genetic transformation, because of its short juvenile period, small canopy, as well as blossom and yield fruit in about one year after seed germination. Moreover, kumquat includes both monoembryonic and polyembryonic genotypes. For the reasons above, the Hong Kong kumquat is expected to become a model plant of citrus. It can be used for conventional breeding as well as function genomics. The main research materials are wild monoembryonic kumquat and polyembryonic kumquats, aiming at obtaining homozygous monoembryonic line through anther culture and self-crossing. Also, this paper compared the transformation efficiency of different lines and the related factors for optimizing the genetic transformation system. The main research results are as follows:1. In 2012 and 2013,By bagging the monoembryonic kumquat located in Huazhong Agricultural University, the first and second self-crossing generation plants were acquired. 31 markers in 9 chromosomes were selected for testing their homozygosity. The results shows that plant1,9,11 have the highest homozygosity by 93.5%. Besides, the homozygosity of each locus in 9 chromosomes were analysed, the highest average homozygosity was chromosome No.6, next one was chromosome No.3 and No.5.2. The second self-crossing generation plants coded by 34,35,36,48,49 had bloomed and set fruits, the third self-fertilization generation plants is expected to get.3. Test for homozygosity of each generation from selfing lines have been conducted by SSR, the results showed that homozygosity of each generation increased lot,the plant viability decreased.4. During June to October in 2012 and 2013, above 10,000 monoembryonic and polyembryonic kumquat anthers were cultured, however, most of them had response and only the 1/2MT medium with 0.1mg/L NAA and active charcoal grew out callus.5. By selecting one monoembryonic genotype and 11 polyembryonic genotypes from different areas as the explants and setting different gradient of factors, the transformation efficiency were studied. By counting the regeneration buds and observing the proportion of resistant buds through fluorescence microscope, the result showed the optimal genetic transformation methods for kumquat. Firstly, treat etiolated seeding of QK,ZQ,GZ samples with 10 days’ light culture, then give them 5-7 days’ darkness culture after co-culture. the OD of bacterium solution is about 0.7. Moreover, heighten the stem length and infection time, cut treated are helpful to some extent.