Dendranthema Grandiflora Tzvelev Research Articles

The Effect of Altering Nitrogen and Sulfur Supply on the Growth of Cut Chrysanthemums

`Dark Yellow Fuji Mefo' chrysanthemums (Dendranthema grandiflora Tzvelev.) were grown hydroponically with either 64, 127, or 254 mg·L-1 N and either 0, 1, 2, 4, 8, 16, 32, or 64 mg·L-1 S in a randomized complete block. Time to flower was measured and symptoms of S deficiency were observed on root, stem, and leaf systems. New leaves and inflorescences were analyzed for S, and lower leaves were analyzed for N concentration. There were four sampling dates and two experiments. Flower diameter was measured when flowers were present, while stem length was measured every sampling date. Nitrogen application could be reduced by half to 127 mg·L-1 as long as some S, 4 mg·L-1 in the fall and 8 mg·L-1 in the spring, was applied. Sulfur deficiency symptoms observed included branchless roots, which aged earlier, overall yellowing of new leaves, and reddening on the leaf abaxial starting from older leaves and moving acropetally. Plants receiving no S had smaller leaves, shorter stems, delayed inflorescence initiation, and restricted inflorescence development. Without S, plants did not produce flowers suitable for commercial sale.

Environmental Influences on Feeding Damage Caused by Western Flower Thrips (Thysanoptera: Thripidae) to Chrysanthemum

The effects of test-location, daylength, thrips density, and choice or no-choice test on feeding damage by Frankliniella occidentalis (Pergande) were studied in chrysanthemum, Dendranthema grandiflora Tzvelev. Under all circumstances, tested cultivars differed significantly in the level of both silver and growth damage caused by thrips feeding on old and young chrysanthemum leaves, respectively. Thrips resistance to both types of feeding damage, measured under the different test circumstances was highly correlated. This means that thrips resistance in chrysanthemum measured in our standardized laboratory experiment gives a good prediction for chrysanthemum breeders who want to select cultivars for thrips resistance under commercial greenhouse conditions. Only test location had an effect on the level of growth damage. In the greenhouse, all chrysanthemum cultivars were more susceptible to growth damage than in the laboratory. The level of silver damage, however, remained constant. Silver damage was only influenced by daylength. All cultivars showed higher levels of silver damage under short daylength compared with long daylength. A density of 10 thlips per plant was found to be high because only 1.6 times more silver damage and 1.1 times more growth damage was found at a 4 times higher thrips density. At the highest density, many thrips died, which resulted in about the same thrips numbers for both treatments at the end of the experiment. Thrips tended to choose among cultivars. However, this did not result in a higher variance in resistance in the free-choice experiment compared with the no-choice experiment.

The role of primary and secondary metabolites in chrysanthemum resistance toFrankliniella occidentalis

The presence of deleterious secondary metabolites to western flower thrips (WFT) (Frankliniella occidentalis Pergande) in several chrysanthemum (Dendranthema grandiflora Tzvelev) cultivars was tested. WFT performance on leaf sap mixed with artificial diet was compared to WFT performance on a control of artificial diet mixed with water. Leaf sap of six of 10 chrysanthemum cultivars tested had a significant negative effect on WFT performance and therefore contained deleterious secondary metabolites. Leaf sap of a resistant and a susceptible chrysanthemum cultivar were fractionated by gel to study the role of secondary metabolites in greater detail. None of the 20 individual fractions obtained had a negative effect on WFT performance, whereas after mixing of these fractions activity was found again. Moreover, WFT performance on the fraction mixture of the resistant cultivar was significantly lower than on the susceptible fraction mixture. The results suggest that WFT resistance in the cultivars studied was caused by several secondary metabolites that had an additional or synergistic negative effect on WFT performance. The role of a deficiency of primary metabolites in WFT resistance of chrysanthemum was also investigated. WFT performance on leaf sap with and without extra primary metabolites (artificial diet) was compared. The variance in WFT performance was significantly smaller when extra primary metabolites were added; WFT performance on leaf sap with and without extra primary metabolites was not correlated. The results suggest that resistance was partly caused by a deficiency of primary metabolites.

DNA Amplification Fingerprinting Identifies Closely Related Chrysanthemum Cultivars

DNA amplification fingerprinting (DAF) was used to study genetic relationships between closely related chrysanthemum cultivars (Dendranthema grandiflora Tzvelev.). Twenty-one cultivars were examined that belonged to the Anne, Blush, Boaldi, Charm, Davis, and Pomona series (families). The genetic variability of cultivars within and between series was evaluated using eleven arbitrary octamer primers. A few polymorphic characters uniquely identified closely related cultivars within each of the series. In contrast, many DNA polymorphisms were observed between members of the different series. Phenetic patterns were established by unweighted pair group cluster analysis using arithmetic means (UPGMA) and principal coordinate analysis (PCO). The average distance between series was 10-fold greater than between cultivars within a series. DNA from all cultivars belonging to a series were also bulked to generate profiles containing unique amplified products for each series. Cluster analysis and PCO of bulked DNA clearly grouped Charm and Pomona together. However, series grouping did not correspond to morphology of inflorescence types. The results demonstrate the utility of the DAF technique in distinguishing clonal materials and its potential use for patent protection, phylogenetic studies, and for identifying useful markers in breeding applications.

Melon Aphid (Homoptera: Aphididae) Control by Inundative Convergent Lady Beetle (Coleoptera: Coccinellidae) Release on Chrysanthemum

Convergent lady beetles, Hippodamia convergens Guerin-Meneville, collected from aggregations in California were released for control of melon aphids, Aphis gossypii Clover, infesting potted chrysanthemum, Dendranthema grandiflora (Tzvelev) ‘Hurricane’, outdoors. Most beetles dispersed from plants within 1-3 d after a single release during May 1993 and July and September 1993 and 1994. Most dispersing beetles left the study area, although some moved within release plots to adjoining plants or dispersed to nearby plots within ≈40 m. Aggregation-collected beetles that were allowed to drink and fly in a screen tent for 7–10 d before release and insectary-reared beetles dispersed more slowly than aggregation-collected beetles that were stored at 4–10°C until the day of release. Although beetles dispersed within days, releases significantly reduced aphid densities during all trials. A single release of 34–42 adult H. convergens per pot provided 25–84% aphid control, calculated according to the Abbott method. Each beetle consumed ≈25–170 melon aphids per day. There was a density-dependent functional response in predation; beetles consumed more aphids when released on plants with higher aphid densities. Release of commercially available convergent lady beetles can provide augmentative control of relatively high aphid densities on small potted plants.

Efeito de diferentes concentrações do meio MS, nitrogênio e sacarose na micropropagação de crisântemo 'orange reagen'

Realizaram-se experimentos objetivando estabelecer concentrações satisfatórias do meio básico a ser utilizado, Murashige e Skoog (MS), de nitrogênio e de sacarose para a propagação "in vitro" de crisântemo (Dendranthema grandiflora Tzvelev.) cv. Orange Reagen. Testaram-se as concentrações 0, 25, 50, 75, 100, 125 e 150% do meio MS combinadas com 0; 0,75; 1,5; 3,0; 6,0 e 12,0% de sacarose. Num segundo experimento, as concentrações 0, 25, 50, 75, 100, 125 e 150% de nitrogênio (em relação ao MS) foram testadas em combinação com as mesmas concentrações de sacarose. Observou-se melhor desenvolvimento de brotos em meios com concentrações entre 50 e 150%, em relação ao MS, combinados com 6% de sacarose. Na concentração de 50% do MS, o tamanho dos brotos obtidos não foi satisfatório. Concentrações elevadas de meio de cultura inibiram a formação de raízes. Verificaram-se resultados semelhantes para as concentrações testadas de nitrogênio. Pode-se então recomendar a utilização de 75% do meio MS com 75% de nitrogênio, acrescido de 6% de sacarose.

Effect of using certified virus‐free cuttings, mulching and floating covers on chrysanthemum production(Dendranthema grandifloraTzvelev cv. Polaris) and incidence of tospoviruses

The use of certified cuttings of chrysanthemum (Dendranthema grandiflora Tzvelev cv. Polaris) had an initial beneficial effect on the incidence of tospovirus infection but had little effect on final incidence. It improved the quantity and quality of production compared with the use of uncertified cuttings. Black polyethylene mulching and floating polypropylene covers provided no protection against the viruses, but polyethylene mulching improved growth. Disease progression was more rapid soon after thrips populations showed greatest abundance. The Gompertz model best explained the virus disease development.

Tospoviruses, weeds and thrips associated with chrysanthemum(Dendranthema grandifloraTzvelev cv. Polaris)

Abstract Under field conditions, impatiens necrotic spot (INSV) and tomato spotted wilt tospoviruses (TSWV) were detected by the dot blot technique in chrysanthemum (Dendranthema grandiflora Tzvelev cv. Polaris) plants having concentric rings and line patterns, from Villa Guerrero and Coatepec de Harinas, State of Mexico. There were 15 species of thrips associated with chrysanthemum in the region, 10 already known and five being described as new species. The known species were: Frankliniella adadusta, F. aurea, F. helianthi, F. inutilis, F. minuta, F. simplex celata, F. occidentalis brunnescens, F. occidentalis dubia, F. occidentalis and Thrips tabaci. From among the aforementioned species, only the last two have been recognized as vectors of tospovirus. Twenty‐six species of weeds were found associated with chrysanthemum, of which, 16 were positive for the TSWV and none for the INSV.

Chemical Characteristics of Chrysanthemum Cause Resistance to Frankliniella occidentalis (Thysanoptera: Thripidae)

Western flower thrips, Frankliniella occidentalis (Pergande), performance on intact chrysanthemums, Dendranthema grandiflora Tzvelev, was compared with that on the sap of squeezed chrysanthemums to examine the importance of plant chemical characteristics. Seventy-six percent of the variation in resistance of intact chrysanthemum cultivars could be explained by the variation in resistance of leaf sap. Thus, the chemical composition of chrysanthemum leaves was a significant factor in resistance to F. occidentalis . Because similarities in resistance were found between Rower sap, leaf sap, and intact, nonflowering chrysanthemums, we suggest there is a chemical resemblance among Rowers and leaves causing thrips resistance in chrysanthemum. Grafts were made between a resistant and susceptible cultivar (cultivars 2 and 15, respectively). A resistance factor was transported from the resistant scion to the susceptible stock, further indicating that chemical compounds play a major role in chrysanthemum resistance to thrips. Relative growth and survival of F. occidentalis larvae was correlated with larval longevity and the resulting feeding damage on intact chrysanthemum cultivars. Thus, growth and survival during the 1st few days can be used as a quick measure of thrips resistance in chrysanthemum.

Biolistic transformation of chrysanthemum with the nucleocapsid gene of tomato spotted wilt virus

In vitro regeneration and biolistic transformation procedures were developed for several commercial chrysanthemum Dendranthema grandiflora Tzvelev, syn. Chrysanthemum morifolium Ramat. cultivars using leaf and stem explants. Studies on the effect of several growth regulators and kanamycin on chrysanthemum regeneration were conducted, and a step-wise procedure to optimize kanamycin selection and recovery of transgenic plants was developed. A population of putative transformed chrysanthemum plants cvs. Blush, Dark Bronze Charm, Iridon, and Tara, was obtained after bombardment with tungsten microprojectiles coated with the binary plasmid pBIN19 containing the nucleocapsid (N) gene of tomato spotted wilt virus (TSWV) and the marker gene neomycin phosphotransferase (NPT II). PCR analysis of 82 putative transgenic plants selected on kanamycin indicated that the majority of the lines (89%) were transformed and contained both genes (71%). However, some transgenic lines contained only one of the genes: either the NPT II (15%) or the TSWV (N) gene (14%). Southern blot analysis on selected transgenic lines confirmed the integration of the TSWV (N) gene into the chrysanthemum genome. These results demonstrate the development of an efficient procedure to transfer genetic material into the chrysanthemum genome and selectively regenerate transgenic chrysanthemum plants at frequencies higher than previously reported.

Low-temperature Limits for Selected Garden Mums

Controlled-freezing tests were conducted in Dec. 1994 and Jan. 1995 to determine cold hardiness of garden mums (Dendranthema grandiflora Tzvelev.) `Baby Tears', `Debonair', `Emily', `Megan', `Ruby Mound', and `Triumph' grown outdoors in central Iowa. Dormant, intact crowns were harvested from the field on 3 Dec. and held at 2 ± 2C until freezing tests began. Crowns were placed in moist cheesecloth, wrapped in aluminum foil, and subjected to –12, –18, –24, or –30C. Cooling was initiated from the storage temperature (2C) at 2 ± 0.5C/h. Treated crowns were allowed to thaw for 24 h at 2 ± 2C. Control and treated crowns then were planted in 3.5-liter (#1) plastic containers using a medium of 2 Canadian sphagnum moss: 2 perlite: 1 field soil (by volume), and transferred to a 21 ± 3C glasshouse for forcing under natural photoperiod. Regrowth data indicate `Ruby Mound' was the least cold hardy selection as most failed to resume growth after exposure to –12C. `Emily', `Megan', and `Triumph' survived exposure to –12C; however, vegetative regrowth was diminished compared to controls. `Baby Tears' and `Debonair' demonstrated no diminution of ornamental utility after exposure to –12C.

Phenotypic differences in transgenic plants of chrysanthemum

AbstractPhenotypic deviations in transgenic plants of chrysanthemum (Dendranthema grandiflora Tzvelev.) cv. ‘White Snowdon’ carrying either whole pTiB6S3 T‐DNA or the GUS gene construct were evaluated. Morphological differences in comparison with the controls were observed not only in regenerated transgenic plants carrying Agrobacterium tumefaciens B6S3 T‐DNA, but also in transgenic plants carrying the GUS gene. The phenotypic changes were stable through several cycles of clonal propagation.

Western Flower Thrips (Thysanoptera: Thripidae) Effects on Chrysanthemum Cultivars: Plant Growth and Leaf Scarring in Nonflowering Plants

The effects of exposure of 12 cultivars of Dendranthema grandiflora Tzvelev and one cultivar of D. pacifica Tzvelev to 20 adult females of the western flower thrips, Frankliniella occidentalis (Pergande), were studied in two no-choice experiments. Thrips damage resulted in large reductions in plant length and leaf area to all genotypes. The values of the damaged leaf area were significantly different among genotypes (range, 0 to >500 mm2 scarred area per plant), and the pattern and the location of the scarring was also different. This damage, however, was not related to the induced reductions in plant growth. For all 13 genotypes tested, the thrips population declined within 4 wk.

RFLP analysis in chrysanthemum. I. Probe and primer development

In order to study genetic variability at the DNA level in chrysanthemum (Dendranthema grandiflora Tzvelev) PstI and HindIII genomic libraries were constructed. Probes from both libraries were tested for the presence of restriction fragment length polymorphisms (RFLPs). Of the probes from the PstI library 91% appeared to hybridize to low-copy genes, while only 35% of those from the HindIII library appeared to do so. The PstI probes were used in further analyses as 79% of them showed RFLPs, whereas the HindIII low-copy number probes gave only 14% polymorphic patterns. Because of the hexaploid character of chrysanthemum, complex patterns generally consisting of 6-12 fragments were visible on a Southern blot after hybridization. To simplify the genetic analysis, locus-specific polymerase chain reaction (PCR) primers were developed that gave simple polymorphic patterns in a number of cases. The RFLP probes and primers developed will be used in future marker-assisted selection in this polyploid crop.

Response of chrysanthemum to uniconazole and daminozide applied as dip to cuttings or as foliar spray

Uniconazole and daminozide were used as dip on unrooted cuttings or as foliar spray on pinched Dendranthema grandiflora Tzvelev. ‘Dalvina’ to control height. Stem elongation was determined on cuttings dipped in solutions of 0, 1.25, 2.5, 5, or 10 mg/L uniconazole or cuttings were dipped and later treated with foliar sprays in concentrations of 1.25/5, 1.25/10, 2.5/10, and 5/5 mg/L uniconazole, respectively. Other plants were sprayed once or twice with uniconazole at 10 mg/L. Daminozide treatments included a pre-plant dip/foliar spray application of 1000/2000 mg/L, respectively, or two foliar sprays of 2,000 mg/L. Uniconazole dip alone retarded stem elongation linearly up to 8 weeks after propagation, 5 weeks after pinching, but was not discernible from the control treatment 8 weeks after pinching. Uniconazole at 2.5/10 and 5/5 mg/L as a dip/spray combination resulted in plants 33% shorter than the control at the end of the production. Doubling uniconazole dip or spray treatments from 5 to 10 mg/L provided no additional reduction of stem elongation. The single uniconazole spray and both daminozide treatments had no effect on final height, although daminozide treatments reduced stem dry weight compared to the control. Stem dry weight was reduced by uniconazole dip/spray combinations compared to dip treatments alone. Similarly, inflorescence and root dry weights were also reduced by the highest uniconazole concentrations. Higher concentrations of uniconazole reduced transpiration on a per leaf area basis up to 47% compared to the control at the end of production. In contrast to previous work, leaf area and leaf thickness increased with some uniconazole treatments, while time to anthesis was not affected by any of the treatments.

504 PB 242 EFFECTS OF IRRIGATION METHOD AND CONTROLLED-RELEASE FERTILIZER RATE ON LEACHATE AND GROWTH PARAMETERS OF CHRYSANTHEMUM

Ground water contamination resulting from continuous liquid fertilization technologies is a serious problem facing greenhouse growers in the United States. Rooted Dendranthema grandiflora Tzvelev. cultivar 'Iridon' cuttings were transplanted into 11 cm pots filled with a 50% peatmoss and 50% perlite (v/v) media containing 0.10, 0.21, 0.42, or 0.84 g N from a controlled release 12-10-17 plus minors fertilizer deposited directly below the transplanted cutting. Pots were assigned to a top-water or subirrigation treatment. Subirrigation reduced the nitrate leachate concentration by as much as 250 ppm as compared with top-watering. Fertilizer N rate linearly decreased plant height in both of the irrigation treatments. Final dry weight of the shoot peaked at the 0.21 g N rate in both the irrigation treatments.

Use of low-cost gelling agents and support matrices for industrial scale plant tissue culture

The efficacies of sago (from Metroxylon sagu Rottb.) and isubgol (from Plantago ovata Forsk.) as gelling agents and those of filter paper, nylon cloth, polystyrene foam and glass wool cloth as support matrices have been tested for the propagation of plantlets of chrysanthemum (Dendranthema grandiflora Tzvelev). The performances of these low-cost gelling agents and matrices were found satisfactory and could compare well with that of agar. Glass wool cloth was, however, found to be the best matrix. Comparative cost estimations of the matrices and gelling agents have been presented and their merits and/or demerits have been discussed. For a given quantity of a medium, sago and isubgol cost about 1/18th and 1/10th respectively, compared to agar (e.g. Sigma, purified agar, No. A. 7921). The corresponding costs of the matrices are also less than that of agar. The results showed the potential of the substitutes for economic commercial application, replacing the costliest, though not indispensable, gelling agent agar.

High night temperatures delay flowering, produce abnormal flowers and retard stem growth of cut-flower chrysanthemums

The responses of chrysanthemum ( Dendranthema grandiflora Tzvelev) cultivars ‘Polaris’ and ‘White Marble’ to night temperatures of 32°C depended on the duration of exposure and the time of transfer to the high night temperature. Transfer for 7 nights at the start of short-day treatment (SD) delayed the onset of flower bud initiation, while transfer for longer, delayed the completion of flower bud formation. When transfer was made for 42 nights from the start of SD, no florets were initiated at the extreme tip of the receptacle in either cultivar throughout the period of transfer. Transfers that delayed flower bud initiation also delayed anthesis, though the effect was generally less. The greatest delay in anthesis occurred when the high night temperature was given at the onset of floret initiation, i.e. between 14 and 21 SD. Transfer at this time also caused the production of more disc florets in ‘Polaris’ and the formation of bracts among the disc florets of ‘White Marble’. Transfer to high night temperature at any stage induced foliar chlorosis and retarded stem extension, though final stem length was not significantly shortened. Attention is drawn to the need to reduce night temperature under black-out covers in summer, especially between 14 and 21 SD, and to some methods of achieving this.

Incomplete block design in plant tissue culture research

Most experiments in tissue culture employ either completely randomized or randomized complete block designs. The ability of orchardgrass (Dactylis glomerata L.) leaf halves and segments from individual leaves of chrysanthemum (Dendranthema grandiflora Tzvelev.) to respond similarly in vitro to identical treatments allows application of an alternative experimental design based on blocking by leaf. Incomplete block designs conserve experimental materials and reduce labor while maintaining the statistical power and efficiency of more conventional designs. They also allow combination with nesting (hierarchal designs) to monitor different sources of variability or with factorial studies. Application of incomplete block designs for orchardgrass (somatic embryogenesis) and chrysanthemum (shoot organogenesis) leaf cultures are presented.

Influence of duration and placement of a high night temperature on morphogenesis of Dendranthema grandiflora Tzvelev

Dendranthema grandiflora Tzvelev. cultivar ‘Choral Charm’ was subjected to 0, 2, 6 or 10 h of a 6°C higher night temperature than day temperature pulse (the term DIF was used to indicate day temperature minus night temperature, hence this treatment involved a negative DIF) just after sunset, around midnight or just before sunrise. Diurnal average temperature was 18.5°C for all treatments. A negative DIF for 2 h after sunset resulted in 11% shorter internodes and 13% lower plant height in comparison with zero DIF. A negative DIF for 6 or 10 h after sunset showed no effect on plant height. This was due to an 8–15% higher number of nodes counteracting 17% shorter internodes. Placing the 2 h period of high night temperature around midnight gave rise to an unexpected 22% increase in plant height. The reason for this was that the negative DIF had no effect on internode length but gave rise to a higher number of nodes, resulting in taller plants. A negative DIF for 6 or 10 h around midnight gave shorter internodes but a higher number of nodes, resulting in no effect on plant height. A negative DIF for 2 h before sunrise gave shorter internodes but the effect was too small to compensate for a small increase in the number of nodes. When applied for 6 or 10 h before sunrise, plant height was 12–17% lower, owing to 17% shorter internodes after negative DIF compared with zero DIF. Compared with control, the number of days to visible bud was decreased only by negative DIF for 2 h before sunrise. Visible buds appeared earlier following negative DIF before sunrise than following negative DIF around midnight. Dry weight production and percentage of dry matter was low compared with control when negative DIF was applied for 2 or 6 h before sunrise and high when applied for 2 h around midnight.