Occurrence of Spontaneous Polyembryony in Lilium lancifolium Thunb

초록

We examined spontaneous polyembryony in Lilium lancifolium Thunb. by determining the occurrence of polyembryonic seeds in intraspecific crosses and open pollination, and by analyzing the genetic origins of polyembryos with simple-sequence repeat (SSR) markers. Forty-one polyembryonic seeds (0.2% of total) were detected from 17,583 seeds. Of the polyembryonic seeds, 36 were duplets and five were triplets. Eighteen seedling sets (three triplets and 15 duplets) were cultured and grown to maturity. Flow cytometry revealed that all were diploids, and results of analyses with SSR markers indicated that all the multiple embryos, except for two triplet seeds, originated from a zygotic embryo through cleavage embryony. The SSR profiles confirmed that the seedlings from polyembryos resulted from cross-fertilizations and did not from unfertilized somatic embryos. Six seedlings rescued from the two triplets occurring in 2x x 3x combinations were heterozygous with respect to SSR, and thus they may have their origin in multiple embryo sacs and/or polyspermy. The occurrence of polyembryonic seeds was remarkably greater in one accession collected from Wan-do (Wan island) than the others. This suggested that the frequency of polyembryony depends on the genotypes of L. lancifolium.

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