English

Abstract

The effect of bulb removal stress on vegetative and flower development of four hybrid lilies at different growth stages and their tolerance to this stress were investigated in this experiment. The tested hybrids were "Royal show" (LA hybrid), "White heaven" (L. longiflorum hybrid), "Sorbonne" and "Premium blond" (Oriental hybrids), four treatments included the bulbs were not removed (control) or removed two, four and eight weeks after planting weeks after planting (WAP) for all cultivars. The results showed that the bulb removal stress had adverse effect on vegetative and flower development of lilies, but the degree of this effect was dependent on the date of bulb removal. It was decreased as the period between planting and bulb removal was increased. Therefore, this stress effect was high when the bulb was removed two weeks after planting (WAP) while it was low when the bulb was removed eight WAP. Thus, the plants at different growth stages have different tolerance levels against this stress and they can survive and successfully complete the life cycle even without their bulbs when these bulbs were removed at late growth stage. The results also showed that the tested cultivars exhibited different response and tolerance to this stress. However, the "Royal show" cultivar was the faster in growth, earlier for flowering and more tolerant with better adapted to bulb removal stress compared to other hybrids.   Key words: Hybrid lilies, vegetative and flower development, bulb removal stress, growth stage.