Interspecfic Hybridization in Lily: The Use of 2n

With the main goal of generating new groups of lilies, that combine agronomic characteristics of major importance, a large number of crosses were performed among the three most important groups of lilies (Lilium), viz., Asiatic, Longiflorum and Oriental; and to some species, to produce F1 inter-specific hybrids. These hybrids, as well as many other F1 hybrids, were sterile and two approaches were used to overcome sterility: i) chromosome doubling through chemicals and ii) the use of naturally occurring or induced unreduced (2n) gametes. The first approach produced many fertile hybrids, however, due to autosyndetic pairing in the allotetraploids, recombination was not detected through DNA in situ hybridization techniques (GISH), and introgression was not achieved. On the other hand, through extensive meiotic analyses and pollen germination tests, we selected hybrids that were able to produce 2n gametes, and in some cases, hybrids in which 2n gametes could be induced. Many plants were obtained in reciprocal backcrosses and recombination as well as introgression was detected through GISH and FISH analyses. In this chapter we present the success in breeding lilies from different taxonomical sections through the use of naturally occurring and induce