F1 distant hybrids between two edible lilies (Lilium brownii var. viridulum and L. davidii var. unicolor) produce more n than 2n functional eggs with more recombinant chromosomes

Lilium brownii var. viridulum (BB) and L. davidii var. unicolor (A(d)A(d)) are grown for edible in China, but their breeding lags far more than other ornamental lily breeding. To improve the situation, F-1 BA hybrids were used as seed parents to cross with A(d)A(d) and other diploid Asiatic lilies (AA). The results showed that the F-1 BA hybrids could produce BC1 progenies. The average seedlings obtained from the combinations per fruit were very variable from 1.7 to 22.5, indicating that their compatibilities were different depending on their males. Among the 18 progenies with genomic in situ hybridization (GISH), ten of them were diploid (2n = 2x = 24), two are aneuploid-near diploid (2n = 2x +/- 1), and other six were allotriploid (2n = 3x = 36); and all of them contain much more recombinant chromosomes and breakpoints than other distant lily hybrids. We concluded that F-1 LA hybrids produced much more n functional egg cells than 2n functional egg cells and this would pay a new way to realize lily ingression breeding at diploid ploidy level.