Abstract: 【Objective】Anther culture is one of the most effective techniques to create new germplasms in modern breeding. Apple is one of the most highly genetically heterozygous and self-incompatible fruit tree. Among the current major apple germplasms, ‘Gala’ cultivar shows traits of early maturity, high yield and enhanced anti-biotic stress, thus is a very important genetic resource for apple breeding programs. Haploid breeding has already been employed to regenerate new germplasm in apple breeding research. In this study, the plantlets were regenerated through embryogenesis during “gala” cultivar anther culture lines to enrich parental apple breeding germplasms. 【Method】The anther culture was used to regenerate gala plants. The ploidy level of regenerated plantlets was determined using flow-cytometry. Subsequently, using selected SSR (HIDRAS) markers, the genotypes of regenerated lines were characterized by gel electrophoresis as well as fluorescent capillary electrophoresis. The anther of ‘Gala’ cultivar collected at early stage were firstly treated at low temperature and then cultured in vitro through embryos induction and differentiation phases and the regenerated plantlets were obtained. The ploidy levels of regenerated plants were analyzed using FACS flow cytometry. To identify the genotype of the plantlets, the DNA was isolated from leaves and then subjected to PCR amplification based on 80 SSR primers selected from the apple HIDRAS database. The homozygous genotypes were determined using both gel electrophoresis and fluorescence capillary electrophoresis. After transplantation, the morphological characteristics of each regenerated plantlet were analyzed.【Result】In the past 3 years, by using the previously optimized anther culture technology, a total of 74 200 ‘Gala’ anthers were inoculated with embryo induction of 0.7% (contaminated anthers over 50 000), resulted in 386 embryos. With differentiation culture, 64 regenerated plantlets survived with regeneration rate of 16.6%. After root induction phase, finally 30 regenerated lines including 28 diploids, 1 haploid and 1 tetraploid were obtained. The PAGE analysis showed that all the regenerated lines were originated from haploid pollen. For genotyping these regenerated plantlets, 17 of 80 SSR markers were further selected (the remaining SSR markers were not polymorphic thus cannot be used for the genotyping) for PCR amplification. Results showed that the panel of 17 SSRs each located in 17 linkage groups, respectively, well distinguished genotypes of the 30 individual regenerated lines. Subsequent morphological observation at the time of 60 days subculture showed that the height of plantlets and morphology of the leaves varied largely. In addition, variations regarding variant ploidy levels were also observed: Gala 5 line was relatively high with wider leaf base, while Gala 7 line showed smaller and thicker leaves and Gala 18 line showed smaller leaves and less amount of leaves. Moreover, diploid plantlets showed a trend of weaker growth than that of the parental ‘Gala’ but stronger than that of haploid and homozygous tetraploid.【Conclusion】By using the technique of anther culture, a set of apple germplasm was successfully obtained and a SSR marker identification system was established. More importantly, the regenerated lines have greatly enriched the apple germplasms and will lay a foundation for apple haploid breeding.

Key words: Gala, anther culture, haploid breeding, SSR markers, homogeneous genotype