1IN VITRO POLLEN SELECTION FOR HEAT-TOLERANCE IN LILIES

Heat-tolerance is an important character for lily bulb and flower production under subtropical and tropical conditions. Since a gametophytic-sporophytic genetic overlap has been demonstrated in many plant species, pollen selection at high temperatures might be an efficient method to achieve heat-tolerance. An in vitro pollen germination assay was performed with a range of lily genotypes at various temperatures (20 to 35°C) to determine the differences in pollen germination and pollen tube growth. At 35°C differences in pollen tube length and percentage of pollen germination were found among accessions. Accessions in which heat-tolerance was expected, i.e. wild types of L. formosanum, L. neilgherense and L. longiflorum, gave the longest pollen tubes at 35°C. An in vitro pollination system was used to select heat-tolerant seedlings within L. longiflorum by pollinating at 25, 30 and 35°C. The preliminary results are discussed. 1