Connecticut King Research Articles

LONG TERM STORAGE OF LILY BULBS AT -2°C

For an efficient maintenance of a lily collection, the maximum storage duration of Lilium bulbs stored at -2°C in moist peat was determined. 'Avignon', 'Connecticut King', 'Enchantment', 'Esther', 'Mont Blanc' (Asiatic hybrids), 'Star Gazer' (Oriental hybrid), 'Gelria', and 'Snow Queen' (L. longiflorum) were used. The viability was determined by the percentage of bulbs with at least one regenerative scale (bulb regeneration), the proportion of regenerative scales (scale regeneration), and ion leakage from inner scales. Maximum storage duration based on bulb and scale regeneration varied between 2.9 and 4.0 years for the Asiatic hybrids and between 2.0 and 2.4 years for the other cultivars. Ion leakage of inner scales was increased for all cultivars at a storage duration of 3 years except for 'Enchantment' and 'Mont Blanc'. It was concluded that a lily collection can probably be effectively stored for 2 years at -2°C in moist peat.

Long term maintenance of an anther-derived haploid callus line of the Asiatic hybrid lily ‘Connecticut King’

A haploid callus line from anther cultures of the Asiatic hybrid lily ‘Connecticut King’ was maintained for a long term. The survival and growth of the haploid calluses were affected by auxins of picloram, α-naphthaleneacetic acid (NAA) and 2,4-dichlorophenoxyacetic acid (2,4-D) and temperatures of 25, 15 and 7 °C during culture. Picloram was more suitable for maintenance of the haploid calluses, whereas NAA and 2,4-D led to root and shoot formation from the haploid calluses. The best temperature for maintenance was 25 °C. About 90% of cells in calluses were maintained in haploid level during 60 weeks of subculture, and about 80% of cells were haploid in the calluses maintained over 2 years with the MS medium containing 4 μM picloram in the dark at 25 °C.

Production of Doubled Haploid Plants Through Colchicine Treatment of Anther-derived Haploid Calli in the Asiatic Hybrid Lily 'Connecticut King'.

An effective method for producing doubled haploid plants of the Asiatic hybrid lily 'Connecticut King' was established with an in vitro colchicine treatment of haploid calli. With an increase in the concentration and duration of colchicine treatment for the haploid calli, both the survival rate and the shoot regeneration from the calli decreased, but the frequency of diploid cells in the callus increased. Treatments of 0.25 and 0.5 mM colchicine for 48 or 72 hrs induced doubled haploid cells and shoot differentiation from calli. Haploid and diploid plantlets were regenerated from colchicine-treated calli, and only haploid plantlets were formed in colchicine-free treatments. This result suggests that these diploid plantlets originated from doubled haploid cells. Double haploids developed bulblets with more scaly leaves with longer stomatal guard cells than did the haploid plantlets.

Cucumber Mosaic Virus on Asiatic Hybrid Lilies in India.

Asiatic hybrid lilies are popular cut flowers with a range of bright colors. Of the several viruses reported from lily (2,3), cucumber mosaic virus (CMV) reduces flower quality and yield (1). Classical symptoms of CMV were observed in recently introduced plants of Asiatic hybrid lilies in Kangra Valley, Himachal Pradesh. The symptoms were mild leaf mosaic, ring spot, transient vein yellowing, occasionally with growth deformation, and flower breaking. Leaf samples from cvs. MonteNegro, Yellow Present, Apeldoorn, Toscana, Connecticut King, and Adelina were collected randomly on the basis of symptom expression. Viral-associated double-stranded RNA (dsRNA) analysis was used to analyze tissue from symptomatic and asymptomatic plants for evidence of a possible cucumovirus. dsRNA analysis resulted in a banding profile typical of that seen with cucumoviruses. There was no evidence of dsRNA in the asymptomatic tissue. Presence of CMV in the symptomatic plants was also confirmed by enzyme-linked immunosorbent assay with antiserum from Agdia (Elkhart, IN). Virus from symptomatic tissues was purified and 30 nm polyhedral, viruslike particles were observed that were subsequently tested for CMV with counter immunoelectrophoresis with antibodies of CMV-C and CMV-D (antibodies obtained from H. A. Scott, University of Arkansas) and ATCC CMV antisera PVAS 242-A. Our isolate differs from other prevalent CMV isolates of Kangra Valley, having a narrow host range and not being readily sap transmissible. However, this isolate is normally transmitted to progeny bulblets. Lack of fallow periods, continuous cropping of other CMV-susceptible bulbous crops, and occasional sprouting of uncollected lily bulblets enhance inoculum build-up. Planting of CMV-tested lilies is recommended to avoid disease losses and to reduce viral inoculum floriculture fields. This is the first report of CMV in Asiatic hybrid lilies in India.

Bulb Quality and Traumatic Acid Influence Bulblet Formation from Scaling in Lilium Species and Hybrids

Scaling is a common commercial technique to propagate Lilium. The present research work evaluated the impact of genotype, traumatic acid (TA), and initial bulb quality on bulblet production by scaling propagation. Genotypes used were: L. longiflorum Thunb. `Snow Queen', L. lancifolium Thunb., one Oriental hybrid (L. × `Stargazer'), and four Asiatic hybrids (L. × `Enchantment', L. × `Connecticut King', L. × `Sunray', L. × `Cote d'Azur'). The genotypes showed a wide variability in the number (1.1-2.6 bulblets per scale) and biomass (83-295 mg per bulblet) of bulblet production. The same variability was exhibited after treatment with TA, which produced an increase of 20% to 40% in the number of bulblets per scale and also a significant increase in their fresh mass (20% to 60%). Using poor quality L. × `Cote d'Azur' bulbs adversely affected the biomass and number of bulblets produced on the scales, and this effect was not overcome with TA treatment. Chemical name used: 10(E) dodeca-l,12-dicarboxylic acid (traumatic acid).

Regeneration of haploid plants from anther cultures of the Asiatic hybrid lily ‘Connecticut King’

A system for producing haploid plants from anther cultures was developed for the Asiatic hybrid lily ‘Connecticut King’. Anthers containing microspores at the mid- to late-uninucleate stages were cultured on MS media supplemented with various plant growth regulators. Microspores containing 3 or 4 vegetative-like nuclei were observed 2 to 3 weeks later, and yellowish nodular calluses appeared within dehisced anthers 2 to 3 months after culture. Picloram was superior to 2,4-d for inducing nodular calluses. Anthers from greenhouse-grown plants required higher concentrations of both picloram and cytokinins than those from field-grown plants and most frequently produced nodular calluses (17.6%) on MS medium containing 2 mg 1−1 picloram and 2 mg 1−1 zeatin. The nodular calluses regenerated many bulblets following transfer to MS medium supplemented with 0.1 or 0.5 mg 1−1 picloram and 0.01 mg 1−1 BA, and the bulblets developed into plantlets (bulblets with scaly leaves and roots) after transfer to MS medium containing 0.1 mg 1−1 NAA. Chromosome counts of root-tip cells of 11 plantlets revealed that five were haploids (2n = 12), two diploids (2n = 24), and four mixoploid. This result suggests that at least some plantlets were of gametophytic origin.

Bulb Quality and Traumatic Acid Influence Bulblet Formation from in Vitro Micropropagated Lilium Species and Hybrids

Micropropagation is an advantageous technique for commercial Lilium propagation. The aim of this work was to evaluate the impact of genotype, traumatic acid [TA, 10(E) dodeca-1,12-dicarboxylic acid] treatment and an initial bulb quality on lily in vitro propagation. Genotypes were: L. longiflorum Thunb. `Snow Queen', L. lancifolium Thunb., one Oriental hybrid (L. × `Stargazer'), and four Asiatic hybrids (L. × `Enchantment', L. × `Connecticut King', L. × `Sunray', L. × `Cote d'Azur'). Assays were done with good-quality bulb genotypes—chosen by water content, sprouting degree, and appearance—with exception of L. × `Cote d'Azur', where poor-quality bulbs were also included. Surface-sterilized 3-mm scale bulb sections where cultured in MS medium with 100 mg·l–1 myo-inositol, 0.4 mg·l–1 thiamine·HCl, 0.1 mg·l–1 NAA, and 3% sucrose and 0.8% agar, pH 5.7. Cultures were kept in darkness at 25°C during 8 weeks. One μM TA was used to immerse half of the explants during 1 hr before culturing. Genotypes showed a wide variability in bulblets' number (1.7–2.9 bulblets per explant) and biomass (55–147 mg per bulblet). The same variability was observed after TA treatment, which produced an increase in bulblets number per explant (14% to 59%) and also a significantly augmented their fresh mass (9% to 42%). Poor-quality L. × `Cote d'Azur' bulbs adversely affected both biomass and number of bulblets produced on the scale sections, which was not overcome with TA treatment. These results suggest the convenience of TA application in Lilium micropropagation protocols on good-quality bulbs, irrespective to the genotype source.

FREEZING OF VEGETATIVE GERMPLASM OF LILY FOR 0 TO 4 YEARS

Germplasm collections of lily are usually maintained in the field leading to high labour costs and to risk of losses caused by diseases. Therefore research has been started aiming to develop storage methods for vegetative material of cultivars and species. In the present study, viability after 0 to 4 years of storage of bulbs in moist peat at -2°C was investigated. The cultivars used were 'Avignon', 'Connecticut King', 'Enchantment', 'Esther' and 'Mont Blanc' (Asiatic hybrids), 'Star Gazer' (Oriental hybrid) and L. longiflorum 'Gelria' and 'Snow Queen'. Viability was scored by the ability of scales to form bulblets. After 4 years of storage, more than 50 percent of the scales of 'Enchantment' and 'Esther' and only a few inner scales of 'Avignon', 'Connecticut King' and 'Mont Blanc' formed scale bulblets. Scales of 'Gelria', 'Snow Queen' and 'Star Gazer' showed enough regeneration for propagation after 2 years of storage, but hardly any regeneration of scales was found after 3 years of storage. These results suggest that Asiatic hybrids can be stored safely for at least 3 years in moist peat at -2°C. 'Star Gazer', 'Gelria' and 'Snow Queen' should not be stored longer than 2 years this way.

THE ESTABLISHMENT OF SUSPENSION AND MERISTEM CULTURES FOR THE DEVELOPMENT OF A PROTOPLAST REGENERATION AND FUSION SYSTEM IN LILY

The present results indicate that established morphogenic suspension cultures can be obtained from crosses between cultivars of L. longiflorum and from a cross between Asiatic hybrid 'Orlito' x 'Connecticut King'. Meristem cultures were obtained from L. longiflorum 'Gelria' and Oriental hybrid 'Star Gazer'. Viable protoplasts can be isolated from these suspension and meristem cultures. The effect of different source tissues and of the culture conditions of the source tissues, on the plating efficiency and regeneration ability of protoplasts, are currently being analysed.

Interspecific hybrids between Lilium 'Oriental' hybrid and L. 'Asiatic' hybrid produced by embryo culture with revised media.

The effects of sugars, phytohormones and amino acids were examined on the growth of excised embryos from compatible crosses in 'Oriental' hybrids (Lilium 'Casablanca' ×L. 'Stargazer') and in 'Asiatic' hybrids (L. 'Connecticut King' ×L. 'Capri'), and also from incompatible crosses of L. 'Casablanca' × L. 'Connecticut King' and L. 'Casablanca' ×(L. auratum × L. nobilissimum ). Embryos obtained from the crosses of the 'Oriental' hybrids could grow on the medium containing more than 3 % sucrose, but not on the medium containing 3 % sucrose irrespective of the addition of phytohormones and amino acids. Similary a higher concentration of sugar was necessary to culture the 'Asiatic' hybrid embryos. The optimum sucrose concentration is considered to be 6 %, since most of embryos on media containing 9 % and 12 % sucrose formed abnormal shoots or stopped growing within two or three months of the culture. When sucrose was partially replaced by mannitol, the survival rate was similar or increased. Addition of mannitol is recommended to adjust a high osmotic pressure of medium. Cytokinins and higher concentration of auxins induced abnormal growth of embryos. Amino acids did not affect growth of embryos. The plants from the cross between an 'Oriental' hybrid and an 'Asiatic' hybrid were obtained on the medium with high osmotic pressure, and these were confirmed to be hybrids by leaf morphology, isozyme analysis and chromosome observation.

Identification of Gibberellins and Abscisic Acid in Bulbs of Lilium elegans Thunb. and Their Quantitative Changes during Cold Treatment and the Subsequent Cultivation.

Abscisic acid (ABA), gibberellin Al (GA1), GA4, GA9, GA12, GA15, GA19, GA20, GA24, GA34, GA44, GA51 and 3-epi-GA4 were identified by full-scan gas chromatography/mass spectrometry (GC/MS) and/or GC/selected ion monitoring (GC/SIM) in purified extracts of dormant bulbs of Litium elegans Thunb. cv. Connecticut King. The findings suggest that two independent GA biosynthetic pathways exist, the early-non-hydroxylation pathway leading to GA4 (active GA) and the early-13-hydroxylation pathway leading to GA1 (active GA). To investigate the physiological roles of ABA and GAs in breaking the dormancy of lily bulbs by cold treatment, quantification of ABA and GAs in the lily bulbs during the cold treatment and the subsequent growth was carried out by GC/SIM, using the corresponding deuterium-labeled compounds as internal standards. The levels of ABA and GA4 increased during cold treatment, reaching a maximum level at the end of the treatment; thereafter the levels decreased rapidly. The level of GA24, a precursor of GA4, also increased during cold treatment and remained elevated, whereas levels of 13-hydroxylated GAs such as GA1, GA19 and GA20 decreased during the cold treatment. The above results suggest that GA4 plays a principal role in breaking dormancy in lily bulbs. The physiological roles of ABA in lily bulbs are also discussed.

Nitrogen dressing and nutrient absorption of lilies (Asiatic hybrids) on sandy soils.

The effect of different amounts (0, 75, 150 and 225 kg/ha) and timings of split application of N on yield and nutrient uptake of 3 hybrid cultivars grown for bulbs was investigated. Efficiency of N-uptake was determined by soil and plant analysis with field experiments in 1983, 1984 and 1985. Leaching of fertilizers applied before planting induced low nutrient efficiencies in sandy soils. Dividing the total N-dressings into 4 monthly applications from Mar. to June or Apr. to July led to a higher N-efficiency, though fertilizers were easily leached with high rainfall. A total of 150 kg N/ha appeared to be adequate. Concentrations of plant nutrients (P, K, Ca, Mg and Na) in mature plants of cultivars Aristo, Connecticut King and Enchantment are presented in relation to bulb yield and N-uptake. (Abstract retrieved from CAB Abstracts by CABI’s permission)

球根雪中貯蔵したユリとリアトリスの生育・開花

To maintain the bulbs or rootstocks at low temperature, those of Lilium×elegans Thunb. cv.‘Benisugata’and‘Connecticut King’, Lilium×formolongi hort, cv.‘Hakuho’and the blazing-star Liatris sp. cv.‘Kouki’were stored in snow occupying a chamber made of 10 cm thick polystyrene panels, from 10 January to 10 May 1988. Some of the snow still remained at the end of storage. Bulb temperature varied from 0 to -0.2°C during storage, but rose to 0.6°C toward the end of the period. The leaf number of the plants increased, but no flower-buds appeared during storage.Lilies and the blazing-star planted on 25 November, 1987 as a control sprouted in late March to middle April and flowered in middle June to early July. However, those planted on 10 May 1988 following storage sprouted in middle May and flowered in early July to early August. The storage caused a decrease in the stem length and node number of‘Hakuho, ’‘Kouki’and‘Connecticut King.’This may have been due to the early initiation of flower-buds at high temperature following planting.

Low light intensity and flower bud abortion in Asiatic hybrid lilies. I. Genetic variation among cultivars and progenies of a diallel cross

When Asiatic lilies are forced during the winter period, additional light is needed to prevent flower bud abscission and flower bud blasting. Growth room experiments showed considerable differences among eight lily cultivars in their response to low light. Among these cultivars, ‘Connecticut King’ and ‘Enchantment’ appeared to be the most sensitive to low light conditions while ‘Uncle Sam’ and ‘Scout’ were the least sensitive.

Growth regulator requirements for adventitious regeneration from Lilium bulb-scale tissue in vitro, in relation to duration of bulb storage and cultivar

Addition of NAA (1-naphthylacetic acid) to the nutrient medium strongly influenced the adventitious regeneration of plantlets from bulb-scale tissue of lilies in vitro. The percentage of regenerating explants, the number of plantlets per explant, and also the bulblet growth of the resulting plantlets were affected by the auxin, low concentrations being stimulatory and high concentrations inhibitory. The cytokinins BA (6-benzyladenine) and 2iP (N6-[Δ2-isopentenyl]-adenine) did not influence the adventitious regeneration, but caused aberrant growth of the regenerated plantlets. Prolonged cold storage of the mother bulbs decreased the demand for exogenous auxin for maximum adventitious regeneration. The optimum for bulblet growth was not affected. Results of experiments with cultivars ‘Pirate’, ‘Enchantment’ and ‘Connecticut King’ suggest an inverse relationship between the in vivo propagation rate by scaling and the NAA demand for optimal adventitious regeneration in vitro.