Asiatic Hybrid Research Articles

Multiple shoot proliferation, bulblet induction and evaluation of genetic stability in Asiatic hybrid lily (Lilium sp.)

An efficient multiple shoot cluster regeneration and micro-bulb induction protocol was developed for Asiatic hybrid lily (Lilium sp.). Highest multiple shoot cluster formation of 78.4 % was observed on MS medium supplemented with 0.25 mg l -1 BAP and 1.0 mg l -1 GA3. The growth regulators, i.e., abscisic acid, daminozide and chlorocholine chloride, significantly affected bulblet quality parameters such as average size, number, fresh mass, and scale count. A dose of 0.1 mg l -1 abscisic acid, 50 mg l -1 daminozide, and 10 mg l -1 chlorocholine chloride exhibited highest micro-bulb regeneration rate per explant of 6.0 ± 0.28, 5.6 ± 0.17, and 6.0 ± 0.34, respectively. A high sucrose concentration of 40 g l -1 also produced highest number of bulblet per explant (6.1 ± 0.05). Amongst the 10 arbitrary decamer primers used to analyze the samples, only 6 primers amplified clear reproducible bands. The 6 primers produced a total of 36 (an average of 6 bands per primer) scorable bands. Phenotypic observations and ran- domly amplified polymorphic DNA (RAPD) analysis established that the regenerated micro-bulbs did not develop any detectable genetic aberration. Thus, the results indicate that in vitro produced bulblets of Lilium spp. (Asiatic hybrid) were clonally identical to their donor plant and were genetically stable.

The novel allele of the LhMYB12 gene is involved in splatter‐type spot formation on the flower tepals of Asiatic hybrid lilies (Lilium spp.)

Many angiosperm families develop spatially regulated anthocyanin spots on their flowers. The Asiatic hybrid lily (Lilium spp.) cv 'Latvia' develops splatter-type spots on its tepals. The splatters arise simply from the deposition of anthocyanin pigments in the tepal epidermis. To determine how splatter development was regulated, we analysed the transcription of anthocyanin biosynthesis genes, and isolated and characterized an R2R3-MYB gene specific to splatter pigmentation. All anthocyanin biosynthesis genes were expressed in splatter-containing regions of tepals, but not in other regions, indicating that splatter pigmentation is caused by the transcriptional regulation of biosynthesis genes. Previously characterized LhMYB12 regulators were not involved in splatter pigmentation, but, instead, a new allele of the LhMYB12 gene, LhMYB12-Lat, isolated in this study, contributed to splatter development. In 'Latvia' and other lily plants expressing splatters, LhMYB12-Lat was preferentially transcribed in the splatter-containing region of tepals. Progeny segregation analysis showed that LhMYB12-Lat genotype and splatter phenotype were co-segregated among the F1 population, indicating that LhMYB12-Lat determines the presence or absence of splatters. LhMYB12-Lat contributes to splatter development, but not to full-tepal pigmentation and raised spot pigmentation. As a result of its unique sequences and different transcription profiles, this new allele of LhMYB12 should be a novel R2R3-MYB specifically associating with splatter spot development.

Growth and flowering physiology, and developing new technologies to increase the flower numbers in the Genus Lilium

The genus Lilium is important as potted plants or cut flowers for horticultural trade and for gardens. However, most of the extensive research on the growth and flowering of this genus was conducted with L. longiflorum Thunb. (Easter lily) forcing large bulbs grown in the field for at least one or two years. Dormancy had to be broken to induce flowering by cold treatment which was given to mature bulbs (vernalization). It would be desirable if the bulb production phase could be bypassed to shorten the total production time, ideally by manipulating the temperature during the bulb programming phase (vernalization methods) and the early greenhouse forcing phase (from potting to flower bud initiation). Information on the physiology of bulb development, controlled flowering, and timing for the Easter, and to certain extent for the Asiatic hybrid lily is readily available. However, information on LA, L. longiflorum × Oriental (LO), and Oriental × Trumpet (OT) hybrid lilies, is not available. The objective of this article is to review factors that control flower numbers and speed of flowering, and to present outlines for producing quality plants of L. longiflorum, L. ×elegans, and LA hybrids, starting from seeds, stem bulbils, and tissue cultured plants, respectively, in a year. Detailed information on the production of L. ×elegans starting from stem bulbils is presented. Cut flowers of Asiatic hybrid ‘Beni no Mai’ with 2 to 3 flowers and strong 60 cm stems were produced in less than a year when mature bulbils, weighing about 400 mg harvested 40 to 50 days after flowering, are treated with a sequential temperature treatment (SEQ CD) 14 to 20 days each at 5°C-15°C-5°C. This production period can be divided into plug production phase from potting the treated bulbils shoot emergence lasting about 200 to 230 days and the second phase from shoot emergence to flowering requiring 90 to 100 days. The increase in the number of flowers could result from the increased shoot apex size and not from the changes in soluble and cell wall neutral sugars.

PRODUCING LATE-SEASON CUT LILY FLOWERS

There is growing interest in the production of field-grown cut flowers in the United States; this increased interest has raised new challenges for the floriculture industry. One of these challenges is to produce fresh cut lily flowers during the late summer and early fall months when demand remains high but availability has dropped. Procedures were developed to produce cut lily flowers from Oriental, Asiatic, and LA hybrid lilies during the late summer and early fall months. A mix of fresh Oriental, Asiatic, and LA hybrid lily bulbs were obtained from The Netherlands and frozen at -1°C upon arrival. Bloom time of the bulbs was staggered by thawing and planting the cold-stored bulbs at two-week intervals beginning at week 26 in June and continuing until week 30 in July. In addition to using frozen bulbs, fresh bulbs from the southern hemisphere were evaluated. In July, fresh lily bulbs of ‘Stargazer’ and ‘Helvetia’ were obtained from Chile. These bulbs had received eight weeks of refrigeration in Chile following harvest in May. The Chilean bulbs were planted every two weeks beginning the last week in July and continuing until late September to determine how late in the season a cut lily flower could be produced. The number of days to flower, the length of the flowering stem, and bud counts were recorded on all flowering stems. Genotypic and environmental differences were noted with all cultivars and several produced excellent cut flowers for late season harvest.

DETECTION OF VIRUSES INFECTING LILIUM SPP. BY RT-PCR AND REAL-TIME PCR

In order to enhance the Italian lily bulb production, a breeding program was carried out at CRA-VIV in Pescia (PT – Italy) during the last years. Asiatic hybrids (Lilium × elegans Thunb.), lily cultivars and other native species were involved in the program. The obtained lily lines, which presented interesting traits, were preserved in a collection. After years of vegetative propagation, some of the new selections showed symptoms referable to viral infections. Virus diseases represent some of the most dangerous threats of Lilium, so the application of fast and effective diagnostic techniques for early detection is very important. The aim of the present study, in the frame of a phytosanitary survey of the lily collection, is to investigate the presence and incidence of Cucumber mosaic virus (CMV), Lilium symptomless virus (LSV), Lily mottle virus (LMoV) and two tospoviruses (Impatiens necrotic spot virus, INSV, and Tomato spotted wilt virus, TSWV). Among the 60 samples object of this study, infections by LSV and CMV were frequently observed. Also LMoV was detected in a smaller amount of samples. All of the samples were negative to INSV and TSWV.

An Asiatic Hybrid Lily ‘Daphne’ with Small Flower and Light Pink and Ivory Bicolor Petals

An Asiatic Hybrid Lily ‘Daphne’ with Small Flower and Light Pink and Ivory Bicolor Petals

English

The objective of the present study was to investigate the effect of different bulb removal dates during plant growth on growth and flowering of Asiatic hybrid lily cv. Brunello. The study was carried out in the nursery of Floriculture Unit, Baghdad University, Iraq, from January to April 2012. During plant growth, the bulbs were not removed (control) or removed four, six, eight and ten weeks after planting. The results revealed that buds number, flowers number, flower diameter and plant height were reduced while number of aborted buds increased when the bulbs were removed during active growth. The degree of bulb removal effect was dependent on date of bulb removal. The effect was severe when the bulbs were removed 8 weeks after planting at which time the plants were at the flower bud development; the plants were shorter and more sensitive to buds abortion and produced less flowers with smaller size compared to other treatments. It is necessary to perform further studies to clarify the relation between the bulb and plant development and to investigate the plant physiological and biochemical changes upon bulb removal during plant growth. Key words: Asiatic hybrid lily, growth, flowering, bulb removal.

절화용 주황색 아시아틱나리 '레드스카이' 품종 육성

A new Asiatic hybrid lily 'Redsky' cultivar was selected from a cross between 'Vivaldi' cultivar with pale pink color flower as mother plant and 'Prato' with orange colored flower in 2000 year. The selected bulb line was propagated and cultivated for line nomenclature as 'Gonong-F-na-10'. The survey of the growth and flower characteristics of 'Gonong-F-na-10' were conducted from 2005 to 2007 on summer cropping system under structure in Highland Agriculture Research Center, NICS, RDA. After all 'Gonong-F-na-10' was named as 'Redsky'. The flowers of the 'Redsky' cultivar had not soft hair and fragrance, and had orange red (O-R N30D) colored petals with dark brown spots in center of flower. The stem color was dark pink and brown caused by anthocyanin pigment, the stigma and pollen colors were brown. Flowering direction was upward. The flowering date was July 7 so early flowering. The plant height was 97.2 cm so long, number of flowers was 4.9 ea, and length of flower bud was 9.3 cm. The bulb weight was about 34.8 g and its bulb size was about 14.8 cm in circumference. 'Redsky' cultivar was registered as a new variety with No. 3119 in Korea Seed and Variety Service on June of 2010.

Pigment accumulation and transcription of LhMYB12 and anthocyanin biosynthesis genes during flower development in the Asiatic hybrid lily (Lilium spp.)

Anthocyanin biosynthesis is often regulated by MYB transcription factors that are classified into AN2 and C1 subgroups. The AN2 subgroup regulates the late genes in the anthocyanin biosynthesis pathway of eudicots, whereas the C1 subgroup controls both early and late genes in monocots. Anthocyanin is a major pigment in Asiatic hybrid lilies (Lilium spp.), with LhMYB12 being the first AN2 subgroup in monocots. In this study, the accumulation of pigments and gene transcripts during flower bud development was evaluated to determine the genes regulated by LhMYB12. LhMYB12 and anthocyanin biosynthesis genes showed the same transcription profiles, with LhMYB12 directly activating the promoters of chalcone synthase and dihydroflavonol 4-reductase. This indicates that LhMYB12 regulates both early and late genes, despite belonging to the AN2 subgroup. The cultivar Landini accumulated anthocyanin and flavonol. The contents of these pigments increased during the late stages of flower bud development; this might result from the coordinated expression of early and late genes. During the early stages of flower bud development, the tepals contained no flavonoids but accumulated cinnamic acid derivatives. These results indicate that the profiles of pigment accumulation and gene transcription in lily tepals are unique among angiosperm flowers.

Regeneration and Agrobacterium-mediated transformation of multiple lily cultivars

To pursue genetic improvement of lily, efficiency of both regeneration and transformation from callus cultures induced from different explants were evaluated in multiple cultivars. Thirty-five callus lines induced from filaments or styles and one control callus line derived from bulb scales of in total twenty lily cultivars representing Lilium longiflorum, Oriental × Trumpet and Longiflorum × Asiatic hybrids were maintained on a medium with 8.3 μM picloram (PIC). In this study, they were tested for their regeneration potential by transferring them onto a regeneration medium supplemented with 0.4 μM PIC and 0.044 μM 6-benzyladenine. Regeneration was obtained in all cultivars examined and the percentage varied from zero to 89 % in the 36 callus lines. Regeneration frequency was significantly influenced by the genotype (cultivar). Subculturing the calli every 4 weeks by refreshing the regeneration medium contributed positively to bulblet formation, when compared to an eight week subculture frequency. It was found that the regeneration ability generally decreased with an increasing age of the callus cultures for all cultivars. The origin of the callus (style or filament) did not lead to significant differences in regeneration frequency, but there was an interaction between callus origin and genotype. Calli of eight randomly chosen cultivars were co-cultivated with Agrobacterium tumefaciens strain AGL0 carrying binary vectors with the gus gene as reporter and putative transgenic plants were produced. GUS histochemical assays demonstrated transient and stable expression of the gus gene in both calli and regenerated lily plants. Transient expression frequencies ranged from 0.3 to 20.6 % while stable transformation was much lower, only 1.4 % as the maximum.

Vermicompost induced changes in growth and development of Lilium Asiatic hybrid var. Navona

Organic agriculture minimizes the negative effects of agricultural activities. The present study was carried out in the factorial experiment on the basis of Complete Randomized Design (CRD) with 4 treatments and 3 replications. The vermicompost used was prepared using bovine manure and the earthworm (Eisenia foetida). Applied vermicompost levels were V0 = 0%, V1 = 10%, V2 = 20%, V3 = 30%. The obtained results from the present research indicated that applied vermicompost especially, at 30% level had significantly improving effects on the accumulation of macro nutrients, Ca and K, and micronutrients, Zn and Fe in both stems and root tissues. Applied vermicompost resulted in better growth and development of vermicompost treated plants as they had higher number of leaves, leaf dry mass, fresh stem and dry weight, stem height and diameter, root number and length. Observed increased contents of gibberellic acid in root tissues resulted from the application of vermicompost. Vermicompost treatments at suitable levels of 20 and 30% had stimulating effects on the number of flowers and their diameters and reducing effects on time of flowering. The result of the present study showed that the use of vermicompost, particularly, with a 30% content had favorable results on the growth and development of the Lilium asiatic hybrid var. Navona. Key words: Biofertilizer, flowering, Gibberellins, humic acid, ornamental plant.

EFFECT OF MODIFIED STEINER NUTRIENT SOLUTION ON MACRONUTRIENT IN ASIATIC HYBRID LILIUM 'BRUNEL'

In order to determine the effect of different concentrations of the universal Steiner nutrient solution on the Asiatic hybrid Lilium 'Brunel' grown in hydroponics under greenhouse a 3×3×3 factorial experiment was carried out. The studied factors were 1) (-30, -50, -70 kPa); 2) N-NH4+ relationship (0, 12.5 and 25% of the total of cation concentration), and 3) H2PO4- anions (80, 120 and 160% with respect to the concentration of this ion in the Steiner solution. The solution was provided daily with a pH ranging between 5.0-5.5. The culture substrate was a local volcanic tuff known as tezontle, whose particle diameter ranged from 1 to 7 mm. Micronutrient analyses to determine Mn, B, Zn, Cu, and Fe were carried out in stem, leaf, and flower. Analyses of variance and mean comparisons (Scheffe) were performed (P≤0.05). It was observed that the selection of levels was appropriate, since the mean level of each factor produced the largest values of B in leaf and Fe in leaf. In addition, with the level combination -70 kPa, 120% H2PO4-, and 0% N-NH4+ the largest concentrations of Mn, Fe, and B in flower, leaf or stem were found. It was also found that the concentration of H2PO4- was negatively related with the concentration of Mn in flower, and/or Fe in stem. Finally, the nutrient solution with the mean level of the three studied factors produced the largest concentration of Mn in the flower of Asiatic hybrid Lilium ‘Brunel’.

GISH analyses of backcross progenies of two Lilium species hybrids and their relevance to breeding

SummaryA total of 21 BC1 progenies of Oriental Trumpet (OT) Lilium hybrids, nine BC2 progenies of OT hybrids, and three BC1 progenies of Martagon Asiatic (MA) hybrids were analysed using genomic in situ hybridisation (GISH). Of the BC1 progenies of the OT hybrids, 15 were euploid (14 triploids, 2n = 3x = 36; 1 diploid, 2n = 2x = 24), and six were aneuploid. The triploid progenies had resulted from 2n eggs due to first division restitution (FDR). The aneuploid progenies had resulted from viable aneuploid gametes. All the BC2 progenies of triploid (2n = 3x = 36) OOT hybrids were aneuploid. Chromosome numbers in the BC2 progenies varied from 25 to 29. Two out of three BC1 progenies of the MA hybrids were aneuploids, with 35 and 32 chromosomes, respectively. Another was a triploid (2n = 3x = 36) which had resulted from 2n eggs due to indeterminate meiotic restitution (IMR). GISH revealed extensive intergenomic recombination in the BC1 progenies of OT and MA hybrids. A large number of Trumpet or Martagon chromosome segments were transmitted to the BC1 progenies from the F1 OT or MA hybrids. However, very few Trumpet chromosome segments were transmitted from the triploid BC1 parent to the BC2 progenies. These results indicate that it should be possible to select cultivars which possessed both traits from these BC1 progenies and they would be fertile.

ユリから検出されたレンブラントチューリップ斑入りウイルス（新称）

In 2009, Asiatic hybrid lily plants with mosaic symptoms were observed in Akita Prefecture, Japan. In a RT-PCR assay, using universal primers for the detection of potyviruses, a potyvirus different from Lily mottle virus was detected. The conserved area of the virus coat protein (CP) shared the highest amino acid (aa) sequence similarity (95.7%) to that of Rembrandt tulip breaking virus (ReTBV). As far as we know, this report is the first on the occurrence of ReTBV in Japan and on the full aa sequence of the CP for this virus.

Cloning of SCA Gene Related to Pollen Tube Adhesion and Oriented Growth and Analysis of Gene Diversity in <i>Lilium spp.</i>

Stigma/style cysteine-rich adhesin genes ( SCA ) were cloned from ‘Tresor’ ( Lilium Asiatic Hybrids), ‘White heaven’ ( Lilium Longiflorum Hybrids) and ‘Caruso’ ( Lilium Oriental Hybrids) leaves by PCR approaches. In this research we obtained four gene copies in both of ‘Tresor’ and ‘Caruse’ genomes and three gene copies in ‘White heaven’ genome. The identities of the cloned SCA among the copies were in the ranges from 72.97% to 99.68%. There are two exons and one intron in all of cloned SCA sequence, which could be deduced immature protein with 113 or 115 amino acid residues (encoding mature protein with 91 amino acid residues) SCA protein contains an N-terminal signal peptide of typical LTP protein, eight conserved cysteine residues and two consensus pentapeptide motifs. The identities among the amino acid sequences were in range from 87.91% to 98.90% higher than that of the similarities of gene sequences. Alignment analysis of amino acid sequences of cloned SCAs showed there were some distinct differences of amino acid site existing in the tested three species of lily hybrids. The phylogenetic tree revealed the relationship of the cloned 11 amino acid sequences of SCA were all more close to LTP family of monocotyledons than that of dicotyledons, which were consistent with the conclusions of kinship in plant taxonomy.

The transcription factor LhMYB12 determines anthocyanin pigmentation in the tepals of Asiatic hybrid lilies (Lilium spp.) and regulates pigment quantity

A single dominant locus determines anthocyanin biosynthesis in the tepals of Asiatic hybrid lilies (Lilium spp.); however the gene that determines this trait has not been previously reported. Furthermore, anthocyanin colour hue in tepals varies between cultivars, but the mechanisms underlying this variation are not known. Here, we show that LhMYB12, which is homologous to petunia An2, determines anthocyanin pigmentation in tepals and that the level of LhMYB12 transcription affects the quantity of anthocyanin pigments, producing colour hue variation in tepals. The pink-tepal cultivars Montreux and Renoir were heterozygous for the LhMYB12 gene. Their F1 population segregated 3:1 for the presence or absence of anthocyanin in tepals, and LhMYB12 cosegregated perfectly with the presence of anthocyanin, indicating that LhMYB12 determines anthocyanin biosynthesis in tepals. Among seven cultivars, a single anthocyanin cyanidin 3-O-β-rutinoside was detected in tepals displaying light pink, pink–red, dark red, or chocolate brown hues. However, concentrations differed according to the following order of colour hue: light pink < pink–red < dark red < chocolate brown, suggesting that colour hue variation in tepals is strongly related to anthocyanin quantities. The accumulation of LhMYB12 transcripts in tepals varied between seven cultivars in the same order, and transcription levels were positively correlated with pigment quantities. This suggests that the levels of transcription of LhMYB12 vary among the different cultivars and subsequently affect the quantities of pigment in tepals. These results indicate that LhMYB12 determines anthocyanin pigmentation and generates the variation in anthocyanin colour hue in lily tepals.

Hot water treatments reduce leaf yellowing and extend vase life of Asiatic hybrid lilies

The vase life of Asiatic lilies can be limited by leaf yellowing, which can be caused by exposure to low light or temperature during winter growth or in storage. We examined the use of postharvest hot water treatments (HWTs) as a means of reducing leaf senescence in stored (4 °C for 2 weeks) and non-stored Asiatic hybrid lily ‘Elite’ ( Lilium sp.). A range of HWTs (45–55 °C for 2.5 or 5 min) was applied to leaves on cut lily stems (but not flowers). Higher temperatures and the longer duration resulted in heat damage, but treatments of 50 °C for 5 min and 52.5 °C for 2.5 min were found to be optimal for minimising leaf yellowing with trace levels of heat damage for both non-stored and stored stems. The onset of yellowing was delayed by 3–4 d, and the occurrence of an unacceptable level of yellowing eliminated for up to 12 d (compared with <6 d for control stems). The physiological effects of these optimal HWTs were examined in terms of water uptake, chlorophyll fluorescence and chlorophyll degradation. Water uptake for optimal HWTs during shelf life was reduced by more than 50% of the control stems. Chlorophyll fluorescence of leaves on control stems showed a reduction in yield ( F v/ F o) over time, which was more marked in lower than upper leaves (thus correlating with yellowing, which was more severe in the lower leaves). Although both optimal HWTs resulted in an initial reduction in yield, there was a recovery over time resulting in a yield that, by 12 d, was as high or significantly higher than control leaves (particularly for the lower leaves). All treatments showed a reduction in chlorophyll content (total, chlorophyll a and chlorophyll b), but control leaves had significantly lower levels after 7 d. HWTs show potential as a non-chemical, simple means of delaying leaf yellowing of Asiatic lilies and thus increasing vase life.

Flower bud abscission triggered by the anther in the Asiatic hybrid lily

It is not well documented which floral parts may trigger the onset of tepal or petal senescence and or flower bud abscission. Asiatic hybrid ( Lilium × elegans Thunb.) ‘Red Carpet’ lily flowers were selected as a model to study this relationship because the various floral organs of a lily flower can be easily dissected and collected for physiological studies. We hypothesized that anther is the organ that triggers flower bud abscission. Ethanol-soluble sucrose, fructose, and glucose were analyzed in the tepal, anther, filament, and pistil. The analysis was conducted on flower buds weighing 1.5 g (small buds) and 3.9 g (large buds). The sucrose content in the anthers of small buds remained high when cut flowers were held at 21 °C for 5 d, suggesting that sucrose is not hydrolyzed into fructose and glucose. However, in large buds, sucrose was not detected when flowers were held at 21 °C for 5 d. The respiration rate of small buds (2.06 g) was high (2000–3000 mg/kg fw) when the tepals were removed and the anther remained attached to the filament, but was low (less than 400 mg/kg fw) in large buds approaching anthesis. Ethylene was produced only in small buds (1.42 g) when the anthers were present. Radioactive 14C sucrose applied to the cut end of the pedicel was translocated rapidly to the anther at harvest, but was not translocated to the anther when abscission was induced by keeping flower buds at 21 °C. Ethylene detected in small flower buds possibly was stimulated by physiological changes resulting from the lack of assimilates available to the anther and the lack of sucrose hydrolysis occurring in the anther. The absence of sucrose hydrolysis in the anther and lack of translocation of sucrose from the filaments to the anther in small buds may be factors that contribute to flower bud abscission in ‘Red Carpet’ lily.

STEM AND LEAF ANATOMY OF HIGHLY ORNAMENTAL REPRESENTATIVES OF THE GENUS LILIUM

The genus Lilium L. is important in the world flower market and morphological characters among species have been investigated. No comprehensive study of stem and leaf anatomy in wild species and hybrid cultivars has been done to date. Thus, the aim of study was twofold - to search for traits of diagnostic value for taxonomic purposes, as well as features to be practically utilized for improving the quality of Lilium-based horticultural hybrids for production as cut flowers and garden ornamentals. Stem and leaf anatomy in Lilium species of high ornamental value was studied using traditional anatomical techniques. The plants for study were grown outdoors and in protected cultivation (forcing) and sampled three times during the season. Morphological and anatomical traits and patterns in the structure of epidermal cells and cortex, thickness of supporting tissue, vascular bundles structure and location are discussed in regards to their diagnostic value and possible practical implementation. The presence of angular collenchyma in the cortex of Lilium ×elegans T.S. Ware, Asiatic hybrids was reported for the first time. The difference in anatomical structure between wild species and hybrids was noted. Anatomical features of diagnostic value, such as epidermal cell structure, vascular bundle and bundle sheath structure are an enriching addition to the most recent taxonomic treatments of the genus.

ETHYLENE AND ANTI-ETHYLENE TECHNOLOGIES IN LILIES

Ethylene is a gaseous plant hormone that accelerates ripening in many fruits and vegetables, and causes senescence in many ornamentals. Lilies are known to be sensitive to ethylene during plant growth, and previous research has shown that long-term (e.g., many weeks) exposure to as little as 0.05 to 0.1 ppm can lead to stunted plants with no market value. Higher concentrations over shorter periods can also injure growing plants. To better understand ethylene effects in lilies, studies were conducted with two Asiatic hybrid lily cultivars (‘Orange Pixie’ and ‘Pink Pixie’) and L. longiflorum ‘Nellie White’. When hybrid lilies (at visible bud stage or ca. 2 weeks later) were exposed to 0.25 or 0.75 ppm ethylene for 1 to 7 days (20°C, in darkness), no injury occurred with 1 day of exposure, but nearly 100% flower abortion was seen with 4 days exposure. Similar results were seen with ‘Nellie White’ with 1 ppm ethylene. Injury was highly dependent on bud size, with buds less than ca. 3 cm being susceptible to 1 day of ethylene (Asiatic hybrid cultivars) and less than ca. 4 cm (‘Nellie White’). The ethylene perception inhibitor, 1-methylcyclopropene (MCP) was highly effective in protecting plants against ethylene. When applied as a foliar spray, MCP at concentrations of 10-50 mg/L (active ingredient) fully protected plants against a 4-d treatment with exogenous ethylene. Initial results using ethephon (an ethylene releasing chemical) as a potential growth regulator for height control in Oriental hybrid lilies are presented.