Establishment and Evaluation of Interspecific Hybrids in Lily Spp

In breeding programs for ornamental bulb crops, interspecific hybridization is one of the most important ways for the introduction of new genetic variation. The genus Lilium generally includes allogamous species with problems of self-incompatibility and the consequent inability to produce seeds when they are self-pollinated. The intraspecific crosses produce a large quantity of seeds, whereas crosses between different species create many problems. The sexual barriers that hamper interspecific hybridization have been classified into pre-fertilization and post-fertilization barriers. A breeding program on lily was carried out at CRA-VIV, former Institute for Floriculture, in Pescia since 2003 with the aim to overcome barriers of interspecific incompatibility and to produce hybrids presenting new ornamental traits from various species. Ovary and ovule culture has been applied for the production of interspecific Lilium hybrids. Several crosses among Asiatic hybrids (‘Golf’, ‘Polyanna’ and ‘Gironde’), Oriental hybrids (‘Lombardia’), and Longiflorum hybrids (‘White Heaven’ and ‘White Magic’) were made by using broken flower buds and the cut-style-method. Other crosses were carried out among Asiatic clones previously selected at the Institute and several wild species like L. pumilum, L. regale, L. aurelian, L. leucanthum and L. ‘New Zealand’. Seven, 14 and 21 days after pollination (DAP) ovaries were cut and in vitro cultivated using 4 different substrates (MSO, LO1, IAA0.5 and NAA1) for 50 and 60 days. Subsequently more swollen ovules were taken out from the ovary and subcultivated on two substrates, IBA0.5, and NAA0.1, for 180 days. Random amplified polymorphic DNA (RAPD) markers were utilized for the early identification of interspecific hybrids. The present research offers the opportunity to obtain interspecific hybrids and to increase the quality of lily, the most important bulbous crop cultivated in Italy.