Effect of three pollination methods on embryo development and seedset in intra- and interspecific crosses between seven Lilium species

Abstract

Interspecific crosses were made between seven Lilium species, viz. L. candidum, L. concolor, L. dauricum, L. henryi, L. longiflorum, L. nepalense and L. rubellurn. A complete diallel cross was carried out between these seven species, including selfand intraspecific pollinations using three pollination methods: normal pollination on the stigma, pollination on the ovary after cutting the style, and pollination on the stigma with the aid of' mentor' (non-functional, compatible) pollen. Embryo rescue, starting 35 days after pollination, was applied to all interspecific combinations. The percentage of successful crosses was about 2.8% after normal pollination, 5.4% after cut-style pollination and 3.8% with the mentor pollen technique. Crosses with L. nepalense were exceptional in that embryos died during the embryo culture phase. Seventeen cross combinations (including 4 reciprocals) yielded 62 embryo plantlets from 839 interspecific pollinations.

Regeneration of flowering plants from difficile lily protoplasts by means of a nurse culture

“…The conventional breeding of lily species has provided novel cultivars with a resistance to viral diseases, a tolerance for unfavorable culture conditions, and an ability to express special flower colors and forms (Van Tuyl et al 1988). For half a century, the limitations of obtaining cross-combinations in lilies because of the incompatibility and incongruity between different varieties have been known (Emsweller and Stuart 1948).…”

“…In order to overcome these difficulties, Watts (1967) obtained the seeds of some selfed plants and achieved many crosses of Lilium by using intrastylar pollination. Van Tuyl et al (1988, 1991 developed and established lily pollination methods for producing interspecific hybrids by utilizing the cut-style technique. However, these methods cannot be used to cover all of the combinations expected.…”

Enhanced seed development in the interspecific cross Allium cepa x A. sphaerocephalon through ovary culture

“…Post-fertilization barriers impeding interspecific hybridization in the Brassicaceae [5] and Liliaceae [6] have been overcome by using ovary culture. Ovary culture methods which support maturation of viable seeds have been developed for A. cepa [7].…”

Production of interspecific hybrids between Lilium longiflorum and L. lophophorum var. linearifolium via ovule culture at early stage

“…Hitherto various techniques have been applied successfully to overcome pre-and post-fertilization of incompatibility. For example, it has been reported that prefertilization barriers can be bypassed by using methods such as the cut style technique, the grafted style method, plant growth regulator treatment, and in vitro pollination (Van Tuyl et al 1988, 1991Li and Niimi 1995;Niimi et al 1999); post-fertilization barriers can be overcome by embryo rescue techniques such as embryo culture (Okazaki et al 1994), ovule culture (Niimi et al 1996), ovules-withplacental-tissue culture (Obata et al 2000), and ovary slice culture (Kanoh et al 1988;Fernández et al 1996;Arzate-Fernández et al 1998;Chi 2002).…”