Volume 5 Number 1 2011

CONTENTS AND ABSTRACTS

Raymond A. Cloyd, James A. Bethke, Richard S. Cowles (USA) Systemic Insecticides and Their Use in Ornamental Plant Systems (pp 1-9)

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Review: Systemic insecticides are compounds that may be applied to plants as a foliar spray or to the soil/ growing medium as a drench or granules. These materials are absorbed by roots or into other tissues and then translocated to plant parts. This may then protect plants from damage associated with phloem-feeding insects such as the Hemipterans including aphids, whiteflies, mealybugs, and soft scales. Factors influencing the activity of systemic insecticides are absorption and translocation, which in turn are affected by plant species, plant age, plant growth rate, environmental conditions, soil/growing medium, and physiological variations of plants. The general advantages of systemic insecticides to ornamental plant systems (greenhouse, nursery, and interiorscape) are that plants are continuously protected for extended periods of time without needing repeat applications; once inside the plant, residues are less susceptible to ultra-violet light degradation or wash-off due to irrigation when applied to soils/growing media; no unsightly residues on plant leaves or stems when applied to the soil/growing medium; plants may be less directly harmful to natural enemies, workers, and consumers; may reduce transmission of plant pathogens; and systemic insecticides may be effective in suppressing insect pests located in areas that are not accessible with spray applications. The disadvantages of using systemic insecticides in ornamental plant systems include potential for secondary pest outbreaks; un-intentional direct and indirect effects on beneficial and non-target organisms; potential leaching from potted plants; increased costs of newer systemic insecticides; and drench or granule applications to the soil/growing medium can be labor intensive. Despite the disadvantages, the use of systemic insecticides is a viable option for long-term protection of ornamental plants associated with greenhouses, nurseries, and interiorscapes for pest management.

María S. Soto, Julián A. Greppi, Gabriela Facciuto (Argentina) Exploration and Collection of Ornamental Germplasm Native to Argentina (pp 10-22)

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Invited Review: Many of the herbaceous ornamentals under cultivation, or their progenitor species, are endemic to South America and these taxa represent a valuable resource for future breeding programs. Argentina has contributed with an important number of ornamental varieties developed from native germplasm. For example varieties derivates from genera such as Petunia, Glandularia, Portulaca, Alstroemeria, Calceolaria and Calibrachoa have been successful and are broadly cultivated around the world. Since 1999, the breeding working group of the Floriculture Institute (INTA-Argentina) has successfully addressed various techniques for the domestication, characterization and breeding of ornamental plants from native species. This work begins with the exploration and collection of native plants and finishes with the development of new varieties. According to latest estimates, the vascular flora of Argentina comprises a total of 248 families, 1927 genera and 9690 species, including 45 endemic genera and 1906 species. Among them, there are many herbs, shrubs and trees with many colorful flowers and these are worthy of being cultivated in our gardens. In this manuscript, we will present the plant explorations methods, planning, organization and logistic and our experience in these topics, emphasizing in ornamental potential of subtropical flora of Argentina.

Verónica Bugallo, Susana Cardone, Maria Julia Pannunzio, Gabriela Facciuto (Argentina) Breeding Advances in Passiflora spp. (Passionflower) Native to Argentina (pp 23-34)

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Original Research Paper: Passiflora is the largest genus in the Passifloraceae family and comprises nearly 500 species. The genus is distributed throughout the tropics and subtropics and the majority of the species are endemic of Central and South America. In Argentina, 19 species grouped in four subgenera are present. P. alata, P. amethystina, P. cincinnata, P. edulis f. edulis and P. umbilicata are the most interesting species for ornamental use due to the size and colour of their flowers. The aim of our breeding program was to obtain new forms for ornamental use. It was also focused in cold tolerance selection. Interspecific crosses have been performed, providing information about the combinatory ability of some species of the genus (P. alata, P. cincinnata, P. caerulea, P. amethystina, P. edulis f. edulis and the hybrid P. ‘violacea’). P. alata and P. caerulea were crossed successfully in both directions, while the other combinations showed unilateral incompatibility. Pollen tube growth was arrested in the style in the crosses P. caerulea × P. amethystina and P. caerulea × P. alata. The knowledge of the site where incompatibility expresses allowed the design of complementary strategies in order to overcome the barriers to hybridization. The chromosome numbers found in parental species and hybrids was 2n=2x=18. Preliminary results about cold tolerance showed that P. caerulea tolerates low temperatures but P. alata and P. amethystina does not. This tolerance was reflected in their progeny.

Kathryn Kamo (USA) Inherited Transgene Expression of the uidA and bar Genes in Lilium longiflorum cv. ‘Nellie White’ (pp 35-39)

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Original Research Paper: The expression of two transgenes, bar and uidA, was studied in Lilium longiflorum cv. ‘Nellie White’ plants. ‘Nellie White’ had been transformed using the gene gun to bombard with pDM327 that contains the bar-uidA fusion gene under control of the CaMV 35S promoter. PCR analysis verified that eight T₀ plant lines were probably not chimeric. Crosses using the eight T₀ plants were made to L. longiflorum cvs. ‘Sakai’, ‘Yin tung’, ‘Snow Queen’, ‘White Europe’, and ‘Flavo’. The bar gene was transmitted to 15% of the 151 T₁ seedlings analyzed with transmission success rates ranging from 0-100% depending on the T₀ plant line. Only 13 of the 22 T₁ seedlings with the bar gene also contained the uidA gene. Expression of the bar gene as determined by immunological detection of phosphinothricin acetyltransferase occurred in all six T₁ plant lines that contained the bar gene. One T₀ parent line had a notably high level of both bar and GUS expression, and this high level expression continued in the T₁ plants. This study indicates that transmission of these transgenes to progeny occurred with low frequency, and expression of both transgenes occurred in the T₁ generation.

Shweta Sen, Surinder Kumar, Minerva Ghani (India) Agrobacterium-mediated Genetic Transformation of Rice Chitinase (chiII) for Fungus Resistance in Chrysanthemum cv. ‘Snow Ball’ (pp 40-44)

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Original Research Paper: Plant regeneration and genetic transformation techniques have been described in internode tissue of chrysanthemum (Dendranthema grandiflora Tzelev) cv. ‘Snow Ball’. Callus was developed on Murashige and Skoog (MS) medium supplemented with 0.5 mg L^-1 6-benzyladenine (BA) and 1 mg L^-1 a-naphthalene acetic acid (NAA). Highest shoot regeneration from callus was obtained with 0.5 mg L^-1 BA, 0.25 mg L^-1 NAA and 1 mg L^-1 gibberellic acid (GA₃). Agrobacterium-mediated genetic transformation was achieved using internode explants and rice chitinase gene (chiII). Highest callus induction was achieved on selective medium containing 10 mg L^-1 hygromycin (Hyg) and 300 mg L^-1 cefotaxime (Cef) after 48-hr pre-conditioning following 96-hr co-cultivation. Highest number of shoots per callus was observed when MS medium was supplemented with 0.5 mg L^-1 BA, 0.5 mg L^-1 NAA, 1 mg L^-1 GA₃, 10 mg L^-1 Hyg and 300 mg L^-1 Cef. Shoots were elongated and multiplied on MS medium containing 0.5 mg L^-1 BA, 0.5 mg L^-1 indole-3-acetic acid and 1 mg L^-1 GA₃. Rooting was accomplished on half-strength MS medium supplemented with 0.2 mg L^-1 indole-3-butyric acid, 0.2% activated charcoal and 5 mg L^-1 Hyg. The putative shoots were hardened with 82% survival in a glasshouse. The transformed plants were analysed for the presence and integration of chiII gene by PCR and southern blot analysis.

Puthiyaparambil Josekutty, Shobha Devi Potlakayala, Rebekah Templin, Sairam Rudrabhatla (USA) In Vitro Flowering Studies with Nine Cultivars of Perennial Ryegrass (Lolium perenne L.) (pp 45-49)

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Original Research Paper: We report here in vitro flowering in six cultivars namely; ‘Banquet’, ‘Gulf annual’, ‘Linn Perennial’, ‘Meridian’, ‘Quartet’ and ‘Tolosa’ of perennial ryegrass (Lolium perenne L.). The frequency of in vitro flowering varied from 2.5% for ‘Tolosa’ to 90% for ‘Gulf annual’. Out of the five media (RM1-RM5) tested to induce flowering in vitro, only RM5 medium (MS salt + vitamin + 0.50 mg L^-1 6-benzyladenine (BA) + 2.0 mg L^-1 thidiazuron (TDZ) + 38.0 mg L^-1 CuSO₄.·H₂O) produced in vitro flowering. Vernalization (one week at 4°C) of the in vitro shoots improved the flowering efficiency by 35% compared to the non-vernalized control. Callus was induced from mature seeds on medium containing MS salts and vitamins with 4.0 mg L^-1 2,4-dichlorophenoxyacetic acid (2,4-D) and 30 g L^-1 sucrose. Unlike previously published reports of callus-based regeneration that requires several months in culture and associated somaclonal variation and albino shoot formation, we obtained normal shoots from mature seed-derived callus in 10-12 weeks.

Saranjeet Kaur, K. K. Bhutani (India) In Vitro Propagation of Dendrobium chrysotoxum (Lindl.) (pp 50-56)

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Original Research Paper: In vitro asymbiotic seed germination of Dendrobium chrysotoxum varied with fruit harvesting time and culture medium used for germinating seeds. Seeds at different developmental stages were harvested and cultured on five asymbiotic orchid seed germination media i.e. defined and undefined media, namely ½ MS, KC, M, MS and PDA. Seeds harvested 220 days after pollination showed maximum germination on all media tested. Amongst the five basal media screened, ½ MS + 3.0% sucrose was the most effective followed by M, KC, MS and undefined medium PDA. Seedlings were formed within 12.35 ± 0.12 weeks. Besides fruit harvesting time, the effect of BA, KN and α-naphthalene acetic acid (NAA) at 1 mg l^-1 each, singly and in combination in ½ MS medium + 3% sucrose (as basal medium), on seed germination and development of seedlings was also assessed. NAA proved optimal for germination and led to early seedlings formation within 10.25 weeks. BA/KN lowered the germination frequency and delayed seedling development whereas their combination with NAA could elevate % seed germination. The efficacy of growth supplements such as banana homogenate (25, 50, 75 g l^-1) and peptone (1.0, 1.5, 2.0 g l^-1) was tested on multiplication of cultures (at the protocorm stage) in ½ MS medium. Seedlings regenerated on all medium combinations, but greatest in organic growth supplemented medium. Protocorm segments formed shoot buds which eventually differentiated into shoots with no intervening callus stage. Among the treatments, highest regeneration frequency, a maximum of 9 shoots/explant, and their accelerated development into plantlets was supported by peptone (2 g l^-1). Robust shoots and root formation was observed with banana homogenate (50 g l^-1). A higher concentration of banana homogenate (75 g l^-1) was detrimental to culture survival.

Tapas K. Bandyopadhyay, Malancha Bandyopadhyay (India), Jaime A. Teixeira da Silva (Japan), Santanu Paul, Anandamoy Dam, Partha D. Ghosh (India) An Efficient Micropropagation Protocol to Control Abnormality in Long-Term Shoot Cultures of Spathiphyllum floribundum (L.)‘Petite’ (pp 57-63)

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Original Research Paper: An efficient in vitro propagation protocol for Spathiphyllum floribundum L. cv. ‘Petite’ was developed after refining different cultural parameters. Treatment with 0.5% sodium hypochlorite followed by 0.1% mercuric chloride, periodic washing in sterilized distilled water and culture in NB medium resulted in 53% contamination-free axillary buds, which served as the explants. White’s (1963) medium, Murashige and Skoog (1962) medium, and its modification supplemented with or without different concentrations of plant growth regulators were tested in order to establish tissue cultures. Modified MS basal medium containing 2.5 µM N⁶-benzyladenine (BA) and 1.0 µM a-naphthaleneacetic acid (NAA) was the most effective medium, with 72.50 ± 4.79% of cultures being established. When BA was increased to 10.0 µM, an average of 6.28 ± 0.52 axillary shoots/explant produced within 6 weeks of initial culture. Secondary subculture with this high concentration of BA in the multiplication medium significantly induced a large number of axillary shoots (8-10/explant) but these became morphologically abnormal after the second subculture. However, if 10.0 µM and 2.5 µM BA were alternated in each subculture, an average of 6.30 ± 0.89 shoots/explant with a mean shoot length of 39.40 ± 2.07 mm were generated. Based on this medium modification, from the third subculture onward an average of 10-15 plants/culture bottle could be directly harvested from the multiplication medium and transferred to the greenhouse for hardening. Small shoots (10-20 mm) present within the clusters were further elongated and rooted in the same basal medium fortified with 0.5 µM BA and 1.0 µM NAA before transfer to the field. The survival rate following acclimatization was 92.50 ± 1.44% and plants grew vigorously after transfer to earthen pots containing soil, coarse sand and cattle manure (1: 1: 1).

Babita Saha, Siraj Datta, Animesh Kumar Datta (India), Jaime A. Teixeira da Silva (Japan) Assessment of Biochemical and Molecular Diversity of Five Elite Gladiolus Varieties (pp 64-67)

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Original Research Paper: Five selected – based on market demand in the floricultural belt of West Bengal, India – Gladiolus (Gladiolus hybridus L.; family: Iridaceae) cultivars (‘White Friendship’ and ‘Red Ginger’ – hilly region cultivars and ‘Green Bay’, ‘Intrepid’ and ‘Sabnam’ – plateau cultivars) were characterized using biochemical (leaf phenolic profile by TLC and assessment of isozymes – esterase and acid phosphatase) and molecular (RAPD profile) markers. A dendrogram constructed following UPGMA revealed interrelationships among and/or between cultivars that could be explored for efficient breeding and improvement.

Mohamed Elimem, Brahim Chermiti (Tunisia) Frankliniella occidentalis (Pergande) (Thysanoptera; Thripidae) Sensitivity to Two Concentrations of a Herbal Insecticide “Baicao 2” in a Tunisian RoseCrop Greenhouse (pp 68-70)

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Short Communication: The sensitivity of Frankliniella occidentalis (Pergande) (Thysanoptera; Thripidae) to two doses of an herbal insecticide based on plant extract “Baicao 2” was estimated by monitoring a thrips population in a rose crop greenhouse. The number of thrips decreased considerably after the first treatment in all treated plots at both concentrations (D1 with 100 ml/l and D2 with 200 ml/l) of “Baicao 2” with mortality rates between 40 and 60% and often with insignificant differences. The efficacy of both concentrations compared with that of the reference product was almost the same with insignificant differences with values of about 83.02, 78.74 and 79.89% respectively for “Baicao 2” dose D1, “Baicao 2” dose D2 and the reference product Tracer^®. On the other hand, complementary treatments using this herbal product are needed to maintain mortality rate around 60% with low thrips number in roses.

Ayushi Kaul, Surinder Kumar, Manisha Thakur, Minerva Ghani (India) Gamma Ray-Induced in Vitro Mutations in Flower Colour in Dendranthema grandiflora Tzelev (pp 71-73)

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Short Communication: Aseptic culture of Dendranthema grandiflora Tzelev cv. ‘Snow Ball’ was used as a source of explant. Isolated nodal segments were established and shoot were multiplied on Murashige and Skoog (MS) medium supplemented with 0.5 mg L^-1 6-benzyladenine (BA), 0.1 mg L^-1 indole-3-aceticacid (IAA) and 1 mg L^-1 gibberellic acid (GA₃). In vitro raised shoots (2-3 cm) were treated with 5, 10, 20 and 30 Gy of gamma rays and multiplied on the same medium. 3-4 cm long shoots were rooted on half-strength MS medium supplemented with 0.3 mg L^-1 indole-3-butyricacid (IBA) and 0.2% activated charcoal. The rooted shoots were hardened and observed for morphological characters. In vitro mutation in flower colour was detected in one branch of the same plant with 10 Gy irradiation. The original floral colour of ‘Snow Ball’ is white with flat and incurving florets. The mutant floret colour was yellow with flat and incurving florets. All ray florets in each flower head and all flower heads in mutated branch were of the same colour and shape. The plants regenerated from mutated branch produced flowers, which were of the same colour/shape, indicating the development of solid mutant in relatively short period of time.

Kolandasamy Padmadevi, Murugaiah Jawaharlal (India) Induction of in Vitro Mutation in Chrysanthemum (Dendranthema grandiflora Tzvelev) Ray Florets (var. Ravi Kiran) using Gamma Rays and EMS (pp 74-77)

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Research Note: Chrysanthemum (Dendranthema grandiflora Tzvelev) is commercially cultivated as a cut flower, loose flower and pot plant. To develop a novel variety with ornamental value, in vitro mutations were induced in var. ‘Ravi Kiran’ using gamma rays and ethyl methane sulphonate (EMS). The mutagens viz., gamma rays (0.5 and 1.0 kR) and EMS (0.1, 0.2 and 0.3%) were used individually and in combination. The treated explants, when cultured in vitro on MS medium fortified with 2.0 mg l^-1 6-benzyladenine, recorded survival rates ranging from 45 to 68%. The mutagenic treatment combination of 1.5 kR + 0.1% EMS took a maximum of 8.5 days to respond (greening of base of ray florets) while the control required a minimum of 4.3 days. Early shoot initiation (11.3 days) was observed in the control while the treatment (1.5 kR + 0.1% EMS) took most days (18.5) to initiate shoots. The number of shoots proliferated decreased as the dose of mutagens increased. Maximum number of shoots was observed in the control (21.3) while fewest shoots were observed in the 1.5 kR + 0.1% EMS treatment (6.5). Microshoots were elongated on MS medium supplemented with 0.04 mg l^-1 GA₃. The minimum period for in vitro rooting (13.5 days) was observed in the control. In the 1.5 kR gamma rays + 0.1% EMS treatment, delayed rooting was observed. The maximum number of roots per plantlet (15.5) was observed in the control. During hardening, maximum survival of plantlets was observed in the control (90.5%), equivalent to the 0.5 kR gamma ray treatment (86.5%). Minimum survival (51.5%) was observed with the 1.5 kR gamma rays + 0.1% EMS treatment. The putative mutants are under observation for desirable mutations.

Javier Sanchéz (Ecuador), Marcos Daquinta, Iris Capote (Cuba), Jaime A. Teixeira da Silva (Japan) Shoot Propagation of Zantedeschia spp. in a Temporary Immersion System – Effect of Culture Parameters on Plant Proliferation and Quality (pp 78-80)

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Research Note: Callas (Zantedeschia spp.), belonging to the Araceae family, are ornamental plants with high commercial demand as pot plants and cut flowers. Traditional propagation techniques are not able to satisfy the rapid introduction of new hybrids onto international markets. Thus, in vitro culture techniques are useful tools for the propagation of new varieties with a wide range of colours. Aiming to establish a simplified and more efficient protocol for the in vitro propagation of callas, the effect of medium volume (10, 20 and 40 ml/explant) and explant wounding (dissected or undissected shoots) on shoot proliferation and quality, were evaluated. The ideal protocol for the efficient in vitro propagation of Zantedeschia var. ‘Treasure’ used 20 ml/explant when dissected shoots were grown in a temporary immersion system.