Potted Gerbera Research Articles

Crescimento e produção de gérbera fertirrigada com solução nutritiva

Este trabalho foi conduzido com o objetivo de avaliar as características de crescimento e produção de quatro cultivares de gérbera de vaso fertirrigadas com duas soluções nutritivas. O experimento foi realizado em casa-de-vegetação, durante o período de maio a julho de 2006, na UNESP-FCA em Botucatu-SP. O delineamento experimental foi de blocos casualizados e constituído em esquema fatorial 4x2, sendo 4 cultivares de gérbera (Cherry, Golden Yellow, Salmon Rose e Orange) e 2 soluções nutritivas. As plantas foram conduzidas em vasos com volume de 1,3 L, preenchidos com substrato composto de 70% de casca de pinus fina e 30% de terra de subsolo. Avaliou-se o número de folhas e diâmetro de planta semanalmente durante o ciclo da cultura; área foliar e fitomassa seca ao final dos períodos vegetativo e reprodutivo; tempo necessário para a produção, número de inflorescências, diâmetro das inflorescências e hastes e altura de planta, no ponto de comercialização. As cultivares responderam de maneira diferenciada quanto às características de crescimento, Salmon Rose e Cherry apresentaram maior formação de parte aérea; Golden Yellow e Orange foram mais compactas. No ponto de comercialização, somente altura, diâmetro de inflorescência e haste apresentaram variação entre as cultivares. As duas soluções nutritivas foram eficientes para a produção de plantas de qualidade.

First Report of Powdery Mildew Caused by Golovinomyces cichoracearum on Gerbera (Gerbera jamesonii) in Italy.

Gerbera (Gerbera jamesonii) is one of the top 10 economically important flower crops in Europe as well as the United States. The acreage devoted to this crop continues to increase especially for use in landscape typologies. Abundant flowering from spring until autumn allows the use of this plant to decorate gardens, terraces, and borders. During the summer of 2009, an outbreak of a previously unknown powdery mildew was observed on potted gerbera 'Mini Yellow' growing in a private garden in Turin (northern Italy). Adaxial leaf surfaces were covered with white mycelium and conidia, and as the disease progressed, infected leaves turned yellow and died. Conidia were hyaline, ellipsoid, borne in chains (three conidia per chain), and measured 16 to 45 × 10 to 30 μm. Conidiophores measured 109 to 117 × 11 to 13 μm and had a foot cell measuring 72 to 80 × 11 to 12 μm followed by two shorter cells measuring 19 to 29 × 11 to 14 and 20 to 32 × 12 to 14 μm. Fibrosin bodies were absent and chasmothecia were not observed in the collected samples. On the basis of its morphology, the pathogen was identified as Golovinomyces cichoracearum. The internal transcribed spacer (ITS) region of rDNA was amplified with primers ITS1/ITS4 and sequenced. BLASTn analysis of the 548-bp fragment showed an E-value of 0.0 and a percentage homology of 99% with G. cichoracearum isolated from Coreopsis leavenworthii (Accession No. DQ871605) confirming diagnosis inferred by morphological analysis. The nucleotide sequence has been assigned GenBank Accession No. GQ870342. Pathogenicity was confirmed through inoculation by gently pressing diseased leaves onto leaves of three healthy potted plants of Gerbera 'Mini Yellow'. Three noninoculated plants served as the control. Plants were maintained in a greenhouse at temperatures ranging between 20 and 30°C. Inoculated plants developed signs and symptoms after 8 days, whereas control plants remained healthy. The fungus present on inoculated plants was morphologically identical to that originally observed on diseased plants. To our knowledge, this is the first report of the presence of powdery mildew caused by G. cichoracearum on gerbera in Italy. Specimens are available at the Agroinnova Collection at the University of Torino. Gerbera is also susceptible to different powdery mildews. Powdery mildew of Gerbera jamesonii caused by Sphaerotheca fusca was reported in Italy (4). G. cichoracearum on Gerbera jamesonii was reported in North America (2), Argentina (3), and Switzerland (1).

DOENÇAS EM CULTIVOS DE GÉRBERA NO ESTADO DO PARANÁ

Em inspeções realizadas em 15 propriedades produtoras de gérbera (Gerbera jamesonii H. Bolus ex Hook. f.) de corte e de vaso, no período compreendido entre o 1º semestre de 2004 e 2º semestre de 2006, abrangendo nove regiões do Estado do Paraná, foram identificados nove agentes causais de doenças: oito de natureza fúngica e uma bacteriana: Erysiphe cichoracearum, Pythium sp., Phytophthora sp., Fusarium oxysporum, Cercospora gerberae, Botrytis cinerea, Albugo tragopogonis, Capnodium sp. e Pseudomonas cichorii. A identificação dos agentes causais das doenças, descrição dos sintomas e épocas de ocorrência, realizados neste trabalho, fornece dados básicos para a realização de futuras pesquisas sobre a epidemiologia e medidas de controle mais adequadas para a cultura da gérbera no Estado do Paraná.

Moving lamps increase leaf photosynthetic capacity but not the growth of potted gerbera

To investigate the responses of leaf photosynthesis and plant growth to a moving lighting system, potted gerberas ( Gerbera jamesonii H. Bolus ex J.D. Hook “Festival”) were grown under supplemental lighting in a greenhouse with either a stationary or a moving lighting system positioned above the benches. The stationary system consisted of a fixed high pressure sodium (HPS) lighting system, while the moving lighting system consisted of a moving HPS fixture attached to a cable system to move the light fixture back and forth over the crop. In both cases, the supplemental lighting was applied from 6:00 to 24:00 h with the same supplemental daily light integral (4.9 mol m −2 day −1). Moving lamps significantly increased leaf photosynthetic capacity as represented by light saturated net CO 2 exchange rate (NCER) ( A sat), light- and CO 2-saturated rate of NCER ( A max), maximum rate of Rubisco carboxylation ( V cmax), maximum rate of electron transport ( J max) and rate of triose phosphate utilization. However, in situ leaf NCER and stomatal conductance, leaf chlorophyll content index, leaf area, leaf thickness, fresh weight of plants were significantly lower under moving lighting than under stationary lighting. It is suggested that the reduced growth of plants under moving lighting might be due to (1) the overall lower light use efficiency of leaves under moving lighting than those under stationary lighting; (2) the slower response time of the photosynthetic system compared to the rate of change in light intensity under moving lighting.

Potted Gerbera Production in a Subirrigation System Using Low-concentration Nutrient Solutions

To determine whether currently used commercial nutrient solution concentrations can be reduced during the final stage (last 4 to 5 weeks) of production of potted gerbera (Gerbera jamesonii `Shogun') under recirculating subirrigation conditions, plants were grown under one of four nutrient levels (10%, 25%, 50%, and 100% of full strength). Nutrient concentration levels did not affect leaf area, flower number and appearance, and plant total dry weight. There were no significant differences in the greenness (as measured by SPAD meter) of leaves from plants that received the 50% and 100% strength nutrient solutions. However, leaves from plants that received the 10% and 25% strength solution showed significantly less greenness than that of the plants that received 50% and 100% strength nutrient solutions. There were interveinal chlorosis symptoms on the younger leaves of some plants in the 10% and 25% strength nutrient treatments. It is suspected that this interveinal chlorosis was due to iron (Fe) deficiency caused by the increased substrate pH. It is concluded that the nutrient solution concentrations typically used for potted gerbera production in commercial greenhouses at the final stage (4 to 5 weeks) under recirculating subirrigation conditions, can be safely reduced by at least 50% without adversely affecting crop production. Nutrient salts accumulated in the top section of the growth substrate under all treatments levels; however, no phytotoxic effects were observed. No differences in water use (141 mL per plant per day) were observed amid the various nutrient levels. Fertilizer inputs were reduced in the 50%, 25%, and 10% treatments by 54%, 75%, and 90% respectively, relative to the 100% treatment. After 4 weeks under recirculating conditions, the qualities of the nutrient solutions were still within acceptable limits.

Current Fertilizer Input for Pot Gerbera Production Can Be Reduced by More than 50%

Pot gerbera (Gerbera jamesonii Var. `Shogun') plants were subirrigated with one of four nutrient solutions (10, 25, 50, and 100% of full strength) in order to determine whether currently used commercial nutrient solution concentrations can be reduced without negative impact on crop production. Nutrient concentration levels did not affect leaf area, flower number and appearance, and plant total dry weight. There were no significant differences in leaf chlorophyll content between the plants that received the 50 and 100% strength nutrient solutions. It is concluded that nutrient solution concentrations typically used in commercial greenhouse, for pot gerbera production, can be safely reduced by at least 50% without adversely affecting crop production. Nutrients accumulated in the top section of the growth substrate under all treatment levels; however, no phytotoxic effect was observed. Fertilizer inputs were reduced in the 50%, 25%, and 10% treatments by 54%, 75%, and 90% respectively. After 4 weeks recirculating, the quality of the nutrient solutions was still within acceptable limits.

The Relationship between Density of Root-knot Nematode and the Damage to Potted Gerbera

The Relationship between Density of Root-knot Nematode and the Damage to Potted Gerbera

Fungos micorrízicos-arbusculares no desenvolvimento de mudas de helicônia e gérbera micropropagadas

Plântulas micropropagadas de helicônia (Heliconia sp) gérbera (Gerbera sp) de vaso, foram aclimatadas em substrato (torta de filtro 50%, solo 30% e areia 20%), inoculado com três espécies de fungo micorrízico (Glomus clarum Nicolson. & Schenck, Glomus etunicatum Becker & Gerdemann e Gigaspora margarita Becker & Hall) e uma mistura destas espécies (inóculo múltiplo). As avaliações quanto ao desenvolvimento da parte aérea e do sistema radicular e porcentagem de colonização, foram feitas aos 60 dias para gérbera e aos 90 dias para helicônia, após transplante. As duas espécies comportaram-se de modo diferente em resposta à micorrização. Glomus etunicatum não colonizou bem nenhuma das duas espécies estudadas. Apesar da elevada colonização, a helicônia não se beneficiou da inoculação, enquanto que a gérbera beneficiou-se da inoculação com G. clarum, G. etunicatum e do inóculo misto.

Callus induction, regeneration of haploid plants and chromosome doubling in ovule cultures of pot gerbera (Gerbera jamesonii)

Gynogenetic plants of pot gerbera (Gerbera jamesonii) were successfully produced from cultures of unpollinated ovulesin vitro. Genotypic variations in the number of ovules that formed callus were found among the lines tested. One particularly responsive genotype was found among 17 genotypes tested where the frequency of callus-forming ovules was 17.5%. Four genotypes formed no callus at all. The frequency of shoot formation from the callus varied from 0-19.6% in nine genotypes. Ploidy was determined by flow cytometry, and 37 (80.4%) regenerants were haploid, seven (15.2%) were diploid, and two (4.3%) were mixoploid with both haploid and diploid cells. The doubling of chromosomes was achieved by treatment with 0.05% colchicine for 2-6 din vitro, and 24.2-34.1% of treated haploid plants were found to have been diploidized.

Callus induction, regeneration of haploid plants and chromosome doubling in ovule cultures of pot gerbera ( Gerbera jamesonii )

Callus induction, regeneration of haploid plants and chromosome doubling in ovule cultures of pot gerbera ( Gerbera jamesonii )