Propagation Of Blueberry Research Articles

Survey of Potential Root Pathogens in Softwood Cuttings Collected from Georgia Blueberry Nurseries

Survey sampling of 16 blueberry nurseries propagating softwood cuttings was conducted in 2007 and 2008 to determine which soilborne plant pathogens were most prevalent in commercial blueberry propagation systems in southern Georgia. Samples were collected four times: June (early), September (mid), and October (late) in the 2007 growing season, with additional sampling of overwintered cuttings in April 2008. This survey revealed that Calonectria ilicicola (Cylindrocladium parasiticum), causing Cylindrocladium root rot, is a primary pathogen of blueberry cuttings in southern Georgia. The organism was isolated consistently during all four survey dates with a cutting-level incidence of 3.6, 10.2, 36.4, and 14.3% in the first through fourth samplings, respectively. Rhizoctonia spp. were recovered less frequently and were only present during the first (10.9% cutting-level incidence), third (4.6%), and fourth survey dates (3.6%), whereas the oomycetes Pythium and Phytophthora were detected only on the second survey date. Fusarium spp. were isolated commonly (29.1% incidence in the first, 12.2% in the second, 18.2% in the third, and 7.1% in the fourth sampling), but pathogenicity remains uncertain. Across all survey dates, Calonectria, Rhizoctonia, oomycetes, and Fusarium were recovered at least once from 43.8, 18.8, 12.5, and 87.5% of nurseries surveyed, respectively. When nursery-level data on pathogen presence or absence collected from this survey were analyzed in relation to a survey of production practices used by these same propagators, the practice of reusing growth media was found to be significantly associated with Calonectria presence.

Pruning management of mini-stumps for mass propagation of blueberry

Abstract: The objective of this work was to evaluate the influence of the pruning management of mini-stumps of the Climax blueberry cultivar, when weekly fertigated, on the productivity of the clonal mini-garden and on the rooting and root vigor of the mini-cuttings. The high survival of the mini-stumps (100%) and production of the mini-cuttings (182.9 mini-cuttings per square meter per month) evidence the high adaptability of the material to successive samplings and to the nutritional conditions provided to the clonal mini-garden, resulting in a high multiplication rate. The rooting percentages obtained at the different samplings remain stable, with a high average of rooted mini-cuttings, reaching 81.7%.

Blueberry Propagation by Minicuttings in Response to Substrates and Indolebutyric Acid Application Methods

The nursery plants supply is one of the most important factors that limites blueberries production in some areas, due to some propagation difficulties observed on this species. In this way, this study aimed to evaluate substrates and IBA application methods on ‘Powderblue’ blueberries (Vaccinium ashei) minicuttings rooting, as well as to verify the rooting development in different periods. The study was divided in two experiments. The first one aimed to evaluate ‘Powderblue’ blueberry minicuttings rooting in three substrates (pine bark, carbonized rice husk and vermiculite) in response to two indolebutyric acid (IBA) application methods: 50% alcohol solution and talc. The second experiment aimed to evaluate ‘Powderblue’ blueberry minicuttings rooting using the best substrate recorded in the first trial (pine bark) and two IBA application methods associated to three periods of rooting access, in order to obtain the ideal rooting period and root development. In the first experiment the rooting percentage presented significant difference among the substrates; the higher percentage of rooted minicuttings occurred in pine bark substrate (68%). Regarding the methods used to IBA application, the talc method was more efficient to promote minicuttings rooting. In the second experiment, it was observed an increase in cutting rooting percentage from 55 to 84%, according to the evaluated seasons; however, the IBA application method did not influence the rooting percentage. Therefore, to produce ‘Powderblue’ blueberry plants from minicuttings it is recommended to use pine bark as substrate and talc as method to IBA application, transplanting the nurseries at 110 days after planting.

Rooting Ability of Hardwood Cuttings in Highbush Blueberry (Vaccinium corymbosum L.) Using Different Indole-butyric Acid Concentrations

Vegetative propagation by cuttings is a very popular method. However, blueberry propagation using cuttings is still a main factor limiting its expansion because its results can vary according to the blueberry cultivar and environmental factors. This study aimed to evaluate the rooting abilities of hardwood cuttings for six blueberry cultivars (O’Neal, Misty, Diana, Biloxi, Bluebeauty, and Coville) using three different exogenous indole-butyric acid (IBA) concentrations (1000, 2000, and 3000 ppm), and to determine if the cutting position (basal, central, apical) affects rooting performance. A control treatment (0 ppm IBA) was also performed. After 90 days of each treatment, rooting percentage, average root length, and average root number per cutting were assessed and used to calculate rooting index, which is a measure of rooting ability. The rooting percentages of hardwood cuttings differed largely among cultivars and were highest for ‘Bluebeauty’ (68.55%), followed by ‘Biloxi’ (68.01%). The rooting index values of these two cultivars (33.59 and 35.18, respectively) were significantly higher than those of the other four cultivars. The rooting response of blueberry hardwood cuttings to IBA concentrations was quadratic, and 1000 and 2000 ppm IBA were sufficient to express the maximum rooting percentage in most cultivars. The rooting abilities of basal, central, and apical cuttings were similar with treatments with high IBA concentrations. The effects of the cultivar, IBA concentration, and interaction between them on rooting percentage, average root length, and average root number were significant; however, the effects of the cutting position on the rooting percentage and average root length were not. This suggested that the rooting abilities of blueberry hardwood cuttings were significantly influenced by the cultivar and IBA concentration rather than by the cutting position.

Effect of biocide addition on plantlet growth and contamination occurrence during the in vitro culture of blueberry

Interest and great demand for blueberry (Vaccinium corymbosum) have increased, as V. corymbosum is now one of the most economically important crops in Korea. It is expected that blueberry production and the area planted for cultivation will increase consistently in the years ahead because of high profitability and the consumer's demand for healthy ingredients. Effective mass production of blueberry is urgently needed for commercial cultivation establishment, but a main limitation is lack of a propagation system that produces a disease-free plant material for commercial plantation. A large amount of research has focused entirely on developing tissue culture techniques for blueberry propagation. However, controlling fungal and bacterial contamination of woody plant material is extremely difficult. Our study was conducted to investigate the effect of biocide addition during the in vitro culture of blueberry on plantlet growth and contamination occurrence. Four biocides, including Plant Preservative Mixture (PPM TM ), vancomycin, nystatin and penicillin G, were used in varying concentrations during the in vitro propagation of blueberry. When nystatin was added into the medium at low concentrations, the overall growth of blueberry plantlets was retarded. Addition of vancomycin and penicillin G in high concentrations decreased contamination but induced plantlet mortality. On the other hand, when 1ml/L PPM TM was added, the growth characteristics of blueberry plantlets did not significantly differ from non-treatment (control), and the contamination occurrence rate was very low. From these results, we found that the addition of the appropriate biocide could provide an effective method to reduce contamination in the culture process, thereby raising in vitro production efficiency.

Effect of fruit size on the growth and development of Andean blueberry (Vaccinium meridionale Swartz) seedlings from four locations in the Colombian Andes

Andean blueberry propagation is done with wild plants and there is an absence of knowledge for the agronomical potential of the available materials for sexual propagation. Therefore, developing a propagation protocol that provides technical information for field growers is needed. The present paper aimed to evaluate the effect of the size of the fruits that were used to extract the seeds on the growth and development of Andean blueberry plants during the germination and nursery stages, comparing fruits from four different regions of Colombia: Antioquia, Cauca, Cundinamarca and Boyaca. During the germination stage, seeds from Antioquia and Cauca showed the best results with germination rates close to 90% and reached important physiological events, such as seed coat cracking and radicle extension earlier than seeds from Boyaca and Cundinamarca. In the nursery stage, fruit size significantly affected the growth variables, such as plant height and leaf length, in all the different seed origins. Seedlings from Boyaca showed better results for growth and development after transplanting, as indicated by a higher amount of leaves and presence of basal branching, followed by seedlings from Cauca, Cundinamarca and Antioquia, which showed delayed phenological events.

Chemical control of Cylindrocladium and Rhizoctonia root rots in blueberry propagation

Cylindrocladium and Rhizoctonia root rots, caused by Cylindrocladium parasiticum and binucleate Rhizoctonia spp., respectively, are common soilborne diseases observed during blueberry propagation in Georgia, USA. Six trials with artificially inoculated propagation medium were completed in a shade-house to determine the efficacy of select fungicides to control these diseases. For Cylindrocladium root rot, two trials with single-drench fungicide applications were made at the time the cuttings (southern highbush blueberry cultivar Rebel) were stuck. In two additional trials, a second drench application was added two weeks later. In all trials, fludioxonil (Medallion) significantly reduced lesion incidence and lesion length. Neither triflumizole (Terraguard) nor thiophanate-methyl (Cleary's 3336) consistently reduced lesion incidence with one application, indicating that a single application of these materials was not sufficient for disease suppression. The second fungicide application improved disease control for all fungicides. However, fludioxonil always performed statistically better than thiophanate-methyl and numerically better than triflumizole as indicated by lesion incidence, lesion length and girdling incidence. For Rhizoctonia root rot, two trials were completed, each with two fungicide applications (when cuttings were stuck and 2 weeks later). Fludioxonil and azoxystrobin (Heritage) significantly reduced lesion incidence and lesion length in both trials. Flutolanil (Prostar) reduced lesion incidence in both trials and also reduced lesion length in the second trial. Pending labeling for this use pattern, fludioxonil, which has provided good control of both diseases in our trials, may form the basis of a fungicide rotation program to supplement sanitation practices for managing Cylindrocladium and Rhizoctonia root rots in blueberry propagation.

Enraizamento de estacas lenhosas de três cultivares de mirtileiro com diferentes concentrações de AIB

Comercialmente, a propagação do mirtileiro por meio de estacas é o método mais utilizado, proporcionando resultados diversos de acordo com a cultivar e a concentração de ácido indolbutírico (AIB) utilizada. Objetivou-se, com este trabalho, avaliar o efeito do ácido indolbutírico no enraizamento de estacas lenhosas de mirtileiro. O material utilizado constituiu-se de segmentos de ramos secundários, com quatro gemas e diâmetro médio de 4,5mm. O delineamento experimental foi completamente casualizado, em fatorial 5x3, com cinco concentrações de AIB (0; 1.500; 3.000, 4.500 e 6.000mg L-1) e três cultivares (Delite, Bluebelle e Briteblue), com quatro repetições e dez estacas por parcela. Após o preparo das estacas, a base destas foi imersa, por 10 segundos, na solução de AIB, sendo colocadas para enraizar em uma mistura de areia de granulometria grossa e substrato comercial Turfa Fértil® com pH de 5,5 na proporção de 1:1(v/v), com irrigação manual. Após 138 dias da instalação do experimento, avaliaram-se a porcentagem de estacas enraizadas, número médio de raízes por estaca, comprimento da maior raiz, número médio de brotações, comprimento da maior brotação e a porcentagem de estacas sobreviventes. De acordo com os resultados obtidos, não foi verificada interação entre os diferentes fatores. Verificaram-se diferenças entre as cultivares nas variáveis comprimento da maior raiz, número médio de raízes por estaca e para porcentagem de estacas sobreviventes. Para concentração de AIB, verificou-se, por meio da análise de regressão, um comportamento linear crescente para as variáveis porcentagem de estacas sobreviventes e enraizadas, porém a resposta foi quadrática para comprimento da maior raiz. Conclui-se que a utilização de AIB em concentração de até 6.000mg L-1 não é suficiente para expressar o máximo potencial de enraizamento nas estacas de mirtileiro das cultivares Delite, Bluebelle e Briteblue.

Fungal Pathogens Associated with Blueberry Propagation Beds in North Carolina

SUMMARY Death of blueberry cuttings in commercial rooting beds was observed due to abiotic and biotic causes. Abiotic causes included poor watering practices, water quality, rooting medium, and inadequate drainage due to poor rooting bed design. Biotic causes were attributable to fungi and included (1) non-pathogenic Basidiomycetes colonizing unsterilized rooting media, (2) airborne or rain-splashed pathogens infecting individual cuttings (Botryosphaeria, Pestalotia and other sp.), and (3) Cylindrocladium sp. that spread radially from the initial infection, producing circular dead spots in rooting beds. Re-use of Cylindrocladium-infested media resulted in complete loss of cuttings. Methyl bromide fumigation was successfully used to sanitize infested media.

Propagation of Blueberry by Softwood Terminal Cuttings in Pine Bark and Peat Media1

Abstract Softwood terminal cuttings of ‘Woodard’ and ‘Tifblue’ blueberry (Vaccinium ashei Reade) rooted best in media containing milled pine bark alone or mixed with equal parts of perlite, compared to sphagnum peatmoss alone or mixed with equal parts of perlite. Percentage rooting, root quality, and percentage marketability of softwood terminal cuttings of Vaccinium ‘Tifton 275’, a complex hybrid of V. corymbosum L. and V. ashei, was unaffected by rooting medium.

Highbush Blueberry Propagation under Southern U.S. Climatic Conditions1

Abstract Hardwood cuttings of highbush blueberry (Vaccinium corymbosum L.) rooted and grew best in a medium of sphagnum peat alone or in mixtures of peat and sand (1:1 and 2:1 v/v) in full sunlight under intermittent mist. Mixtures of peat and sand are recommended because root breakage is a problem when separating plants produced in peat alone. A commercial rooting hormone was of no value in increasing rooting.