Fertility analysis and 2n gametes induction of Lilium FA hybrids ‘Jiaoyang’ in short growth period

  Objective  This paper aims to explore the fertility of pollen and female gametes of Lilium FA hybrids ‘Jiaoyang’, and to improve and restore the fertility of gametes by artificial induction, so as to apply it in polyploid introgression breeding.

  Method  The pollen fertility of L. FA hybrids ‘Jiaoyang’ was observed by the method of acetic acid magenta staining, and the process of meiosis of its pollen mother cells was observed. 2n gametes were induced by colchicine injection, and 2n pollen fertility was verified by hybridization with L. davidii var. unicolor. In order to explore the fertility of female gametes, L. FA hybrids ‘Jiaoyang’ was used as female parents crossed with L. davidii var. unicolor through direct pollination and cut-style method. The fertility of female gametes was measured by the expansion rate of ovary, the number of embryo seeds and the germination rate.

  Result  During the meiosis of pollen mother cells, there were unequal segregation of chromosomes and cytoplasm in L. FA hybrids ‘Jiaoyang’, which produced a large number of aneuploid microspores, could not develop into fertile pollen, resulting in no fertility. After colchicine treatment, some 2n pollen was produced. The optimum concentration of colchicine was 0.10%, and the highest induction rate was 86.00%. The female gametes were fertile and produced aneuploidy gametes. By cut-style method, the ovary expansion rate increased from 11.91% to 65.02%.

  Conclusion  Colchicine can induce 2n pollen production and restore certain fertility in the pollen of L. FA hybrids ‘Jiaoyang’, while the female gametes can be fertile, and the embryo seeds can be obtained and germinated crossed as the female parent. The study on the fertility of L. FA hybrids ‘Jiaoyang’ is helpful for further introgression among different groups of lilies, and is of great value for cultivating new varieties with excellent comprehensive characters.