IMPROVEMENT OF BREEDING EFFICIENCY FOR INTERSPECIFIC HYBRIDIZATION OF LILIES IN KOREA

Abstract

Interspecific hybridization of lily in Korea is focused on increasing breeding efficiency especially under Korean climate conditions. Cultivars derived from L. formolongi were propagated by seed and were sensitive to day length. These cultivars differ from flowering time with the Asiatic and Oriental hybrids. Therefore, to breed interspecific hybrids by using L. formolongi, the use of stored viable pollen is a prerequisite. Lily pollen was stored at four different temperature conditions for one year and pollen viability was investigated using three different methods. As storage temperatures increased, pollen viability was drastically reduced. Viability of lily pollen stored was maintained effectively at temperatures lower than -20°C. FDA test was the most effective and convenient method to ascertain pollen viability. To overcome pre-fertilization barriers in interspecific hybridization of lilies, pollen tube growth in the stigma or style, and the penetration of pollen tubes into the ovules were observed. OA (Oriental Asiatic), OL (Oriental Longiflorum), FA (Formolongi Asiatic), and FO (Formolongi Oriental) hybrids were obtained through embryo rescue and stigmatic and CSM pollination, while AO (Asiatic Oriental), AL (Asiatic Longiflorum), LA (Longiflorum Asiatic) and LO (Longiflorum Oriental) hybrids were not obtained through these methods. Backcrosses were used in order to reduce scattered petals in interspecific hybrids. It was possible to obtain BC107 hybrids between FA (Fomolongi Asiatic) and Asiatic hybrids as male parent. But, it was difficult to obtain BC1 hybrids between FA hybrid and L. formolongi as female parent. Normal pollination was better than CSM (Cut style pollination method) to get BC1 hybrids. In order to overcome the sterility of interspecific hybrids pollen, low concentration of oryzalin was more effective than high concentration of colchicine to obtain tetraploid. The fertility of pollen increased by about 40% in tetraploid level. Fusarium oxysporum screening test was carried out. ‘Hae-wool’, ‘Sinavro’ and FA 96-16 were classified as highly disease resistant and ‘Supia’ and ‘Doran’ as moderately resistant to Fusarium bulb-rot. The FO-hybrid lilies from NHRI were susceptible.