Propagation Of Cuttings Research Articles

The rooting performance of shea (Vitellaria paradoxa gaertn) stem cuttings as influenced by wood type, sucrose and rooting hormone

Vegetative propagation of stem cuttings of different physiological woodtypes of Vitellaria paradoxa was studied in a polythene propagator. The treatments included combinations of wood type (soft, semi-hard and rejuvenated (coppiced) shoots), sucrose application at 0, 15 and 25%, and Seradix ‘3’ powder hormone (active ingredient- indolebutyricacid) at 0 and 8000 ppm. Cuttings of rejuvenated shoots dipped in 15% sucrose solution gave significantly higher rooting and longer roots than both softwood and semihardwood. High levels (P < 0.05) of soluble sugars and total free phenols were recorded for coppiced cuttings which resulted in better rooting performance than the other wood types. Cuttings dipped in Seradix ‘3’ powder hormone significantly recorded higher rooting than the control (no hormone).

Enraizamento de estacas de Cana-do-Brejo

A propagação vegetativa de espécies medicinais vem despertando o interesse de pesquisas agronômicas já que se constitui em ferramenta básica para qualquer cultivo em escala comercial. Neste contexto, este trabalho objetivou avaliar a propagação por estaquia da cana-do-brejo, considerando o tipo de estaca, a presença de folhas e o tipo de substrato no enraizamento. Foram utilizados dois tipos de substrato: areia e um composto 3:2:1 (terra, areia e húmus). Foram utilizadas estacas da porção apical e mediana, com folhas inteiras, meia folha e sem folha. O delineamento experimental foi inteiramente casualizado, com 10 repetições e esquema fatorial 3 x 2 x 2. Aos 60 dias foram avaliados a porcentagem de sobrevivência das estacas, o número de raízes, número de brotos, comprimento de maior raiz e a biomassa seca das raízes. Foram verificados o maior enraizamento e maior número de brotos nas estacas apicais com folha e meia-folha. Nas estacas medianas e apicais sem folha não se observou enraizamento efetivo nos substratos utilizados.

Photosynthetic Daily Light Integral during Propagation Influences Rooting and Growth of Cuttings and Subsequent Development of New Guinea Impatiens and Petunia

A majority of commercial propagation of herbaceous ornamental cuttings occurs during the winter when the photosynthetic daily light integral (DLI) is relatively low. We quantified how the mean DLI influenced rooting and subsequent growth and development of two popular vegetatively propagated species, New Guinea impatiens (Impatiens hawkeri Bull.) and petunia (Petunia ×hybrida hort. Vilm.-Andr.). Three cultivars of each species were propagated under a mean DLI ranging from 1.2 to 10.7 mol·m−2·d−1. Cuttings were rooted in a controlled greenhouse environment maintained at 24 to 25 °C with overhead mist, a vapor-pressure deficit of 0.3 kPa, and a 12-h photoperiod. Rooting and growth evaluations of cuttings were made after 8 to 16 d. In a separate experiment, rooted cuttings under DLI treatments were then transplanted into 10-cm containers and grown in a common greenhouse at 21 ± 2 °C under a 16-h photoperiod to identify any residual effects on subsequent growth and development. In both species, rooting, biomass accumulation, and quality of cuttings increased and subsequent time to flower generally decreased as mean propagation DLI increased. For example, root number of petunia ‘Tiny Tunia Violet Ice’ after 16 days of propagation increased from 17 to 40 as the propagation DLI increased from 1.2 to 7.5 mol·m−2·d−1. In addition, cutting shoot height decreased from 6.3 to 4.5 cm, and root and shoot dry biomass of cuttings harvested after 16 days of propagation increased by 737% and 106%, respectively. Subsequent time to flower for ‘Tiny Tunia Violet Ice’ from the beginning of propagation decreased from 50 to 29 days as propagation DLI increased from 1.4 to 10.7 mol·m−2·d−1 regardless of the DLI provided after propagation. In New Guinea impatiens ‘Harmony White’, root and shoot dry weight of cuttings increased by 1038% and 82%, respectively, and subsequent time to flower decreased from 85 to 70 days as the propagation DLI increased from 1.2 to 10.7 mol·m−2·d−1. These experiments quantify the role of the photosynthetic DLI during propagation on the rooting and subsequent growth and development of vegetatively propagated herbaceous ornamental cuttings.

First Report of Cucumber mosaic virus Infecting Solanum jasminoides in Italy.

Solanum jasminoides Paxton (potato vine or jasmine nightshade) is a vegetatively propagated ornamental species within the Solanaceae family. Recently, symptomless plants of this species were reported as natural hosts of the quarantine pest, Potato spindle tuber viroid (PSTVd) in Italy (1). In January 2008, approximately 1,000 potted, 2-year-old plants of S. jasminoides growing in an ornamental nursery in Sicily showed virus-like mosaic and malformation of leaves. Symptoms were observed on approximately 60% of the plants. Leaf tissue, collected from 30 symptomatic and 10 symptomless plants, was analyzed by double-antibody sandwich-ELISA with polyclonal antisera specific to Cucumber mosaic virus (CMV), Tomato spotted wilt virus, and Impatiens necrotic spot virus (Loewe Biochemica, Sauerlach, Germany). The same samples were also analyzed by tissue-printing hybridization with a PSTVd-specific digoxigenin-labelled riboprobe. All the symptomatic samples tested positive only with antisera against CMV, but negative in all other tests. The symptomless samples were negative in all the performed tests. To confirm the association of CMV with the diseased plants, total RNA was extracted from the same samples (RNeasy Plant Mini Kit; Qiagen, Hilden, Germany) and analyzed by reverse transcription (RT)-PCR using CMV-specific primers MP+5'-CATGGCTTTCCAAGGTACCAG-3' and MP-5'-CTAAAGACCGTTAACCACCTGC-3' that amplify a 844-bp fragment from the MP gene (2). The expected fragment was amplified only from samples of symptomatic tissue. CMV was also detected in mother plants grown in the same nursery and showing same mosaic symptoms. Definitive identification of the pathogen was obtained by cloning and sequencing the RT-PCR product. The obtained sequence (GenBank Accession No. EU828783) had 99 and 98% similarity with the subgroup I-A isolates CMV-LUN (GenBank Accession No. EU432183) and CMV-Fny (GenBank Accession No. DI0538), respectively. To our knowledge, this is the first report of CMV infecting S. jasminoides and it adds a new host to the more than 1,000 species (85 plant families) infected by this virus. The high incidence of the disease in the nursery could be due to propagation of cuttings from an infected source.

Effect of two substrates and different irrigation levels in the propagation of rosemary (Rosmarinus officinalis L.)

Existe poca informacion sobre laminas de riego y de sustratos adecuados para la propagacion de romero bajo invernadero, que permitan al productor aprovechar la capacidad productiva total de la planta. Bajo condiciones de estres, el romero limita la produccion de biomasa seca y fresca. Se evaluo el efecto de dos sustratos y diferentes laminas de riego en la propagacion del romero. Se realizo un diseno experimental completamente al azar con diez tratamientos, producto de la combinacion de cinco laminas de riego (coeficientes multiplicadores de la evapotranspiracion 0,6; 0,8; 1; 1,2 y 1,4) y dos sustratos: suelo negro (SN) y mezcla de suelo negro y cascarilla de arroz quemada (ME); cada tratamiento tuvo cuatro repeticiones para un total de 40 unidades experimentales (UE). El mejor coeficiente (lamina) para la propagacion de esquejes de romero fue uno. El mejor sustrato para la propagacion de romero es ME en proporcion 1:1 en volumen. El sustrato ME presento una mayor eficiencia en el uso del agua (EUA) que el suelo negro de paramo. Una mayor cantidad de agua genero mayor longitud de ramas. La mayor produccion de biomasa fresca y seca, se obtuvo con la aplicacion del coeficiente de riego de uno y el sustrato ME

A Survey of Water and Fertilizer Management During Cutting Propagation

The objective of this study was to quantify water volume and nutrient content leached during propagation of herbaceous cuttings in commercial greenhouses. Nutrient concentrations in the fertigation solution, substrate, tissue, and leachate were measured between Jan. and Mar. 2006 at eight greenhouse locations in Michigan, Colorado, New Hampshire, and New Jersey. Grower management of the timing and concentration of nutrients applied to vegetatively grown calibrachoa (Calibrachoa ×hybrida) or petunia (Petunia ×hybrida) liner trays varied among the eight locations, ranging from 0.5 to 80 mg·L−1 nitrogen (N) in week 1 and from 64 to 158 mg·L−1 N in week 4. Over a 4-week crop period, applied nutrients averaged 4.9 g·m−2 N, 0.8 g·m−2 phosphorus (P), and 5.8 g·m−2 potassium (K), and leached nutrients averaged 1.1 g·m−2 N, 0.3 g·m−2 P, and 1.6 g·m−2 K. Leaching of nutrients and irrigation water was highly variable among locations. Leached water volumes ranged from 4.5 to 46.1 L·m−2 over 4 weeks and contained 0.29 to 1.81 g·m−2 N, 0.11 to 0.45 g·m−2 P, and 0.76 to 2.86 g·m−2 K. The broad range in current commercial fertigation practices, including timing of nutrient supply, concentration of applied fertilizer, and leaching volume, indicate considerable potential to improve efficiency of water and fertilization resources during propagation and reduce runoff.

First Report of Tomato spotted wilt virus on Coprosma repens (Mirror Bush) in Italy.

Coprosma repens A. Rich. (mirror bush, Rubiaceae) is a hardy salt tolerant shrub that is native to New Zealand where it is primarily a coastal weed. In temperate climates, many variegated varieties and hybrids of mirror bush grow extensively in gardens. In February 2007, irregular or semicircular necrotic spots, sometimes in concentric rings, were noticed on leaves of approximately 2,000 potted, 1-year-old plants of C. repens 'Tapuata Gold' obtained as cuttings from a nursery located in Catania Province. The symptoms were detected on approximately 60% of the plants and were localized exclusively on older leaves especially in the yellow or white border. Protein A sandwich (PAS)-ELISA showed mirror bush was positive for the Batavian lettuce strain of Tomato spotted wilt virus (antiserum to TSWV: PVAS-450 from American Type Culture Collection, Manassas, VA). Double antibody sandwich (DAS)-ELISA with polyclonal antisera to Cucumber mosaic virus, TSWV, and Impatiens necrotic spot virus confirmed the presence of only TSWV. Reverse transcription (RT)-PCR was employed to characterize the TSWV isolate. RT-PCR was carried out with primers (forward 5'-TTA ACT TAC AGC TGC TTT-3' and reverse 5'-CAA AGC ATA TAA GAA CTT-3') specific for the CP gene of TSWV (3). Amplification was performed in a thermal cycler (Gene Amp PCR System 24000; Perkin Elmer, Hayward, CA) by preheating at 94°C for 5 min followed by 30 cycles of 1.5 min of denaturation at 94°C, 2 min of annealing at 48°C, and 1 min for extension at 72°C. Finally, the amplified DNA was incubated at 72°C for 7 min for a final extension. All samples yielded DNA fragments of the expected size of 823 bp, which included the entire N gene. Purified PCR products were cloned and sequencing (GenBank Accession No. EU020104) was done by Sequiserve (Vatterstetten, Germany). Comparison with sequences available from the GenBank database showed 96 to 99% homology with the same region of the genome for all TSWV isolates, thus confirming the identity of the virus as an isolate of TSWV. In the Rubiaceae family, TSWV was previously detected on Galium spp., Ixora spp., Gardenia jasminoides Ellis, and Bouvardia sp. (1,2,4). To our knowledge, this is the first occurrence of this virus on a member of the genus Coprosma. The high incidence of the disease in the nursery could be due to propagation of cuttings from an infected source.

Enraizamento de estacas de Pau-Brasil (Caesalpinia echinata Lam.) tratadas com ácido indol butírico e ácido naftaleno acético

O pau-brasil (Caesalpinia echinata Lam.) tem grande valor cultural no Brasil e a sua propagação por sementes é dificultada pela rápida perda do poder germinativo delas. A estaquia pode ser usada para a produção de mudas de espécies florestais, principalmente quando existem algumas dificuldades de propagação por sementes. Este trabalho teve como objetivo caracterizar o efeito de concentrações e fontes de auxinas sobre o enraizamento de estacas de pau-brasil. Estacas com cerca de 12cm de comprimento e de um a dois pares de folhas foram tratadas na base com ácido indol butírico (AIB), ácido naftaleno acético (ANA) na forma líquida ou na forma de pó nas concentrações de 0, 1.250, 2.500, 5.000, 10.000mg L-1 ou mg Kg-1, respectivamente. As estacas foram transferidas para substrato contendo areia e mantidas sob nebulização (90-95% UR). Aos 120 dias de estaquia, foram avaliados a mortalidade, a retenção foliar, a formação de calo e a percentagem de estacas enraizadas. As estacas apresentaram índices de sobrevivência de até 70%. A formação de calos não foi relacionada com a concentração de auxinas utilizadas. O maior índice de enraizamento de estacas de pau-brasil, em torno de 16%, foi resgistrada com a utilização do ácido indolbutírico (AIB) e do ácido naftalenoacético (ANA) na concentração 2.500mg L-1. Os altos índices de sobrevivência e os baixos índices de enraizamento sugerem que as estacas devem permanecer por mais tempo sob nebulização, a fim de induzir o seu processo de enraizamento.

Rigitano: nova cultivar de umezeiro para porta-enxerto de pessegueiro

A pesquisa brasileira não havia desenvolvido, até o presente momento, um porta-enxerto clonal para a cultura do pessegueiro com características agronômicas desejáveis, especialmente com relação à resistência a nematóides-de-galha, facilidade de propagação por estacas herbáceas e indução à melhoria da qualidade dos frutos da cultivar-copa. O presente trabalho tem por objetivo apresentar a cultivar Rigitano de umezeiro, selecionada e aprovada para constituir um novo porta-enxerto para a cultura do pessegueiro. Identificada inicialmente como 'Clone 10', a cultivar Rigitano é resultante de um amplo projeto de pesquisa, realizado a partir de 1998 em colaboração com material procedente do Instituto Agronômico de Campinas (IAC), na Faculdade de Ciências Agrárias e Veterinárias (FCAV/UNESP), Câmpus de Jaboticabal (SP). Os trabalhos de seleção e multiplicação para validação técnico-científica final iniciaram-se com experimentos de propagação por estacas herbáceas, cujos resultados indicaram viabilidade do método nas quatro estações do ano, nas condições climáticas de Jaboticabal (SP). A enxertia com o pessegueiro 'Aurora-1', borbulhia em escudo ou escudo modificado, demonstrou ser viável em porta-enxertos de maior diâmetro (± 10 mm). Em condições de campo, 'Rigitano' revelou-se o menos vigoroso dos clones de umezeiro testados. Além disso, 'Rigitano' é resistente a Meloidogyne javanica e M. incognita, entretanto é suscetível a Mesocriconema xenoplax. Os resultados de campo, como porta-enxerto da cv. Aurora-1 de pessegueiro, revelam boa produtividade e frutos com boas qualidades pomológicas e tecnológicas. Os resultados de pesquisa obtidos revelam amplas possibilidades de sucesso da cv. Rigitano em sua validação como novo porta-enxerto de pessegueiro, bem como seu uso visando à redução do espaçamento de plantio e à produção de frutos de melhor qualidade.

Repeated exposure of jacket plum (Pappea capensis) micro-cuttings to indole-3-butyric acid (IBA) improved in vitro rooting capacity

The objective of the trial was to determine an effective propagation protocol for jacket plum (Pappea capensis) tree species. Experiments on in vitro propagation and rooting of stem cuttings were carried out. Dipping stem cuttings in half strength Murashige and Skoog (MS) media for 12 h prior to application of rooting hormones improved bud break and prolonged survival of stem cuttings on a mist bed. Early leaf loss was observed for stem cuttings planted without MS treatment. However, rooting was poor (11% for cuttings pre-treated in MS and 0% for those not pre-treated). For micro-propagation, significant differences (P<0.05) in shoot multiplication and root regeneration were found. MS media supplemented with 2.0 mg l–1 benzylaminopurine was superior in the number of micro-shoots produced. Rooting capacity of micro-cuttings was improved from 42% to 64% when MS media supplemented with 0.5 mg l–1 IBA were repeated for the micro-cuttings that initially failed to root. There was 70% survival rate of plantlets after hardened off.

Influence of Indolebutyric Acid Potassium Salt on Propagation of Semi-hardwood Stem Cuttings of Bougainvillea

Bougainvillea glabra is a tropical species with reportedly difficulty to propagate. Previous research has shown the importance of talc-based rooting hormones when propagating Bougainvillea, yet little has been published on the efficacy of liquid-based formulations. Therefore, our objective was to determine the optimum concentration of indolebutyric acid potassium salt (KIBA) needed to effectively root semi-hardwood stem cuttings of Bougainvillea `California Gold' and `Helen Johnson'. Sub-terminal cuttings measuring 6.5 cm were harvested from stock plants of Bougainvillea on 3-week intervals from 6 June to 8 Aug. and repeated 6 Sept. to 8 Nov. 2005. Cuttings were dipped 0.5 cm in a solution of 0, 1500, 3000, or 6000 mg·L-1 KIBA or in a 1500-mg·L-1 solution containing indolebutyric acid (IBA) 1%: napthaleneacetic acid (NAA) 0.5% and propagated under mist. Cuttings were evaluated for percent survival, rooting quality (1 = poor; 5 = best), and number of primary and lateral roots 5 weeks after planting (WAP). Differences in `California Gold' for percent survival, average rank, and number of roots were determined not significant at P ≤ 0.05. However, application of rooting hormone to `Helen Johnson' increased rooting quality, number of primary roots, and number of lateral roots by up to 24%, 53%, and 50%, respectively. Results indicated rooting performance was generally improved with application of KIBA; therefore, cuttings of Bougainvillea may benefit from a 1500-mg·L-1 solution. KIBA was also found to be as effective as the industry standard liquid formulation. Growers will have to consider the availability and cost of KIBA when propagating Bougainvillea.

Propagation of Wollemi pine from tip cuttings and lower segment cuttings does not require rooting hormones

Domestication of the recently discovered and highly endangered Wollemi pine has relied almost entirely upon serial propagation of cuttings from a very small conservation collection. This study assessed the requirement for applied auxin to induce rooting in tip cuttings and lower segment cuttings of Wollemi pine. Both types of cuttings proved easy-to-root, with mean rooting of 71% for tip cuttings and 82% for lower segments. Auxin application (at 1.5, 3.0 or 8.0 g indole-3-butyric acid/L) did not accelerate root protrusion from propagation tubes or affect final rooting percentages.

DAILY LIGHT INTEGRAL INFLUENCES ROOTING AND QUALITY OF PETUNIA CUTTINGS

DAILY LIGHT INTEGRAL INFLUENCES ROOTING AND QUALITY OF PETUNIA CUTTINGS

Propagation by Stem Cuttings and Response of Seeds to Light and Temperature of Fever Tea (Lippiajavanica)

Fever tea (Lippiajavanica) is one of the important medicinal plants belonging to the Verbenaceae family. The first objective of this investigation was to study the propagation of fever tea using stem cuttings. The main variables studied were cutting position, rooting media and rooting hormone. The germination requirement of fever tea seed is also not known. Therefore, the second objective was to investigate the ideal seed germination temperature and light combinations. Germination was tested at constant temperature regimes (15, 20, 25 and 30 °C) with a continuous light or dark period and at alternate temperatures of 20/30 °C and 16/8 hour (light/dark) combinations, respectively. For the stem cutting investigation, sampling was done every 5, 10, 15, and 20 days from plant establishment. Apical cuttings took less time to root than basal cuttings regardless of growing medium. Response of cuttings to rooting hormone was growing medium-related. With rooting hormone, it took 10 days to root most of the apical cuttings, whereas basal cuttings showed more roots in 15 to 20 days after plant establishment. Cuttings in sand took 5 days longer to root than in pine bark, regardless of rooting hormone. Therefore, for quicker establishment of fever tea stem cuttings, rooting hormone and pine bark should be used for propagation of both apical and basal cuttings. In the germination investigation, it was found that fever tea seeds are positively photoblastic. Regardless of temperature, seeds failed to germinate in continuous darkness. The germination percentage was improved at continuous or alternating temperatures above 20 °C with continuous light. However, the germination percentage decreased with alternating light and dark treatments.

CUTTING PROPAGATION WITH AUXIN APPLIED VIA THE ROOTING SUBSTRATE

Stem cuttings of golden euonymus (Euonymus japonicus `Aureo-marginatus'), shore juniper (Juniperus conferta `Blue Pacific'), white indian hawthorn (Rhaphiolepis indica `Alba'), and `Red Cascade' miniature rose (Rosa `Red Cascade') were successfully rooted in plugs of a stabilized organic substrate that had been soaked in aqueous solutions of the potassium salt of indole-3-butyric acid (K-IBA) at 0 to 75 mg·L–1 before inserting the cuttings. Cuttings were rooted under intermittent mist in polyethylene-covered greenhouses with rooting periods appropriate for each species. Rooting percentages showed some increase with increasing auxin concentration with juniper cuttings, but were similar among treatments for the other three species. Number of roots per rooted cutting increased with increasing auxin concentration with cuttings of juniper, Indian hawthorn, and rose, and was greatest using around 60 mg·L-1 K-IBA for cuttings of juniper and Indian hawthorn and 30 to 45 mg·L-1 K-IBA for cuttings of rose.

NON-MIST VEGETATIVE PROPAGATION BY RESOURCE-POOR, RURAL FARMERS OF THE FOREST ZONE OF CAMEROON: SOME TECHNOLOGY ADAPTATIONS TO ENHANCE PRACTICE

SUMMARY The vegetative propagation of leafy stem cuttings of high-value tropical trees using non-mist propagators is an important part of the World Agroforestry Centre's tree domestication programme. As the programme develops in the region, the need to scale-up the technology is becoming urgent. A vegetative propagation technology that is robust, adaptable and attractive to small-scale rural farmers without the need for an expensive extension system is crucial for success. This report is part of a larger on-going study to evaluate the constraints in the practice of vegetative propagation of poor rural farmers in the forest and humid savannah zones of southern, central and western Cameroon, and to tailor technology to their means and realities. The study was carried-out, through participatory on-the-spot analysis and practical evaluation of innovations with farmers following end of year group reflection meetings within the course of agroforestry research and development activities at pilot nurseries in Cameroon. The main findings are that among the farmers who practise vegetative propagation of high-value fruit and medicinal trees under non-mist conditions:- • the problem of water level management inside the non-mist propagator ranks very high; • the adoption of non-mist vegetative propagation by poor farmers will be greatly enhanced by:- - reducing costs of materials, using locally available materials were possible, and - tailoring the technology to farmer capacities, time management schedules and household division of labour.

EVAPOTRANSPIRATION–BASED MISTING CONTROL FOR POINSETTIA PROPAGATION

Theoretical development and validation of a modelbased misting control system for propagating poinsettias(Euphorbia pulcherrima Freedom Dark Red Willd. ex Klotzsch) are presented. The control system predictsevapotranspiration (ET) using the PenmanMonteith combination model, with the canopy surface resistance term replacedby an equivalent surface resistance that includes the combined resistance effects of plant stomata, water uptake, propagationmedium, and leaf adaxial surfaces. Different combinations of incident radiation (Ri) and air vapor pressure deficit (VPDair)were used to validate this technique by comparing measured and estimated values of ET of partially rooted cuttings underpartially wetted conditions. Under dark conditions, four ranges of VPDair were applied (0.8 to 1.1, 1.3 to 1.6, 1.8 to 2.1, and2.3 to 2.6 kPa). Under light conditions, three levels of Ri (100, 200, and 300 W m2) were combined with three ranges of VPDair(1.3 to 1.6, 1.8 to 2.1, and 2.3 to 2.6 kPa). Observed and predicted values of ET under dark conditions were in remarkableagreement, with the ET model overestimating actual ET by 6% and 8% at root emergence and after one week, respectively.During light conditions, predicted ET was at most 14% larger than observed values. The use of predicted ET in misting controlfor propagation of vegetative cuttings has several advantages over other techniques, such as timerbased scheduling andtechniques that account for only Ri or VPDair, by applying only enough water to maintain water status of the cutting.

Hábito de frutificação e produtividade do tomateiro propagado vegetativa e sexuadamente na Amazônia Oriental

O trabalho foi realizado de julho a dezembro de 1999, em campo na Embrapa Amazônia Oriental, objetivando comparar quantitativa e qualitativamente o potencial de mudas de tomateiro obtidas através de enraizamento dos ramos das ponteiras, e da planta matriz, oriunda de semente, da cultivar C-38-D Novo, usando a técnica de Tomaticultura em Gramado. Observou-se que as plantas obtidas a partir do tecido adulto das ponteiras do tomateiro, ramificam menos e ocupam menor espaço, possibilitando maior densidade de plantio, e consequentemente, aumento da produtividade. As mudas de ponteira apresentaram a velocidade de floração e de frutificação mais lenta e constante, permitindo a produção de frutos, com peso médio acima de 60 g, durante 70 dias de colheita; enquanto que as plantas matrizes tiveram o período de floração e de frutificação antecipado e concentrado em curtos períodos, sem poder manter o peso médio mínimo, 60 g, de interesse na comercialização, a partir de 30 dias de colheita. A produtividade das plantas propagadas vegetativamente foi igual à das plantas oriundas de sementes botânicas (71,7 kg versus 72,6 kg por 20 plantas/6,28 m²). Embora os dados obtidos sejam preliminares, a propagação via enraizamento da ponteira mostrou ser uma alternativa importante para o cultivo comercial. Inclusive, esse método pode viabilizar a comercialização de material de difícil obtenção e alto custo e acelerar o uso de material segregante de alto valor.

Genotypic variability of rooting capacity in Coffea arabica L. cuttings

Cutting propagation of coffee trees has been used for several years in Coffea canephora because of the advantages of this technique compared to seed propagation. Recently, the production of heterotic arabic coffee hybrid genotypes increased the importance of conventional and biotechnological cloning also for C. arabica. Two experiments were carried out to assess cutting rooting of several C. arabica genotypes. In greater detail, the potential of two types of cutting of several hybrid genotypes compared to C. canephora genotypes was investigated. The experiment was carried out under shading with automatic misting in boxes of partially burnt rice husks during the summer months. There is genetic variability for cutting rooting capacity among the C. arabica genotypes. The F 1 hybrids tended to perform better than the lines. Single-node soft-wood cuttings were superior to the tip cuttings. Selection only for cutting rooting characteristics and useable cuttings resulted in efficient selection especially among single-node soft-wood cuttings. In spite of the large observed difference between the cutting production of C. arabica and C. canephora, in some cases C. arabica genotypes can be obtained with rooting performance very close that observed in C. canephora.

Cytokinin-like activity of N, N′-diphenylureas. N, N′-bis-(2,3-methylenedioxyphenyl)urea and N, N′-bis-(3,4-methylenedioxyphenyl)urea enhance adventitious root formation in apple rootstock M26 ( Maluspumila Mill.)

Vegetative propagation of cuttings is a widespread method to multiplicate plants. Adventitious root formation is a key step in vegetative propagation and considerable progress has recently been made in understanding root formation. But, in spite of the efforts made, no new rooting treatments have been developed. Here, we report for the first time, that N, N′-bis-(2,3-methylenedioxyphenyl)urea and N, N′-bis-(3,4-methylenedioxyphenyl)urea enhance adventitious root formation in microcuttings of Malus pumila Mill. rootstock M26. Roots emerge without auxin supplementation in the darkness, transfer in hormone free medium, or callus formation. With the use of different bioassays, we also demonstrate that these two diphenylurea derivatives do not show cytokinin- or auxin-like activity.