Time filter

Source Type

Garcia-Lopez E.,Institute Fitosanidad Fitopatologia | Mora-Aguilera J.A.,Institute Fitosanidad Fitopatologia | Villegas-Monter A.,Institute Fitosanidad Fitopatologia | Villegas-Monter A.,Institute Recursos Geneticos y Productividad | And 3 more authors.
Plant Disease | Year: 2016

Malformation disease is an important disease of mango (Mangifera indica L.) worldwide. This disease was first observed in 2008 in mango orchards in the Azua and Peravia provinces of Dominican Republic. Vegetative symptoms included loss of apical dominance, and swollen apical and lateral buds; fasciculated, thickened, and misshapen stems with shortened internodes and dwarfed leaves. From July to September 2013, malformed vegetative shoots were collected in mango ‘Keitt’ orchards located in Azua de Compostela County with a disease incidence from 1 to 40%. Pieces of symptomatic tissue were surface sterilized in 1% sodium hypochlorite for 2 min, rinsed three times in sterile distilled water, dried for 10 min, and transferred to potato dextrose agar medium (PDA). The petri plates were incubated at 28°C for 5 days in a 12-h photoperiod. The most frequent fungal colonies were purified, and monosporic cultures obtained in PDA. Fungal colonies developed aerial mycelium, producing orange to red pigments in the medium after 3 days of incubation. Macroconidia were slender, slightly falcate, with a beaked apical cell and a footlike basal cell, and were 3 to 7 septate and 24.2 to 58.8 × 2.5 to 3.5 μm. Microconidia were ovoid or oval, with 0-septate conidia abundant and 1-septate conidia less common, 6.5 to 9.3 × 2.2 to 3.3 μm, and usually aggregated in false heads. Coiled sterile hyphae were observed; chlamydospores were absent. The fungus was identified as Fusarium pseudocircinatum according to descriptions by Leslie and Summerell (2006). To confirm the identification, DNA was extracted from a pure culture (Azua-1) and the translation elongation factor 1-alpha (TEF-1α) and beta-tubulin (BT) gene regions were amplified by PCR using primers EF1/EF2 and BT1/BT2 (Kvas et al. 2008). Sequences were deposited at GenBank (Accession Nos. KT253884 and KT253885). BLAST analysis of these regions showed 99% identity with sequences of F. pseudocircinatum (GU737398, AF160271, GU737390, and GU737391). To verify the pathogenicity, the isolate Azua-1 was used to inoculate 10 healthy 6-month-old mango ‘Puntica’ seedlings by infiltration of 30 μl of a conidial suspension (2 × 106 spores/ml) with a hypodermic needle into an apical bud. Ten control plants were infiltrated with 30 μl of sterile distilled water. Plants were maintained in a nursery at 27 ± 2°C. All inoculated plants developed typical vegetative malformation symptoms after 11 months, whereas no symptoms were observed on the control plants. The fungus was reisolated only from malformed plants by incubating diseased shoot pieces in PDA, fulfilling Koch’s postulates. This fungus only has been reported causing mango malformation disease in Mexico (Freeman et al. 2014). Urgent actions are necessary to protect 4,370 ha of high-quality mango production in Dominican Republic and the promising mango export trade from this disease. Special attention is needed in production areas intensively managed with practices such as pruning, water stress and grafting. © 2016 The American Phytopathological Society.


Nunez Ramos P.A.,Instituto Dominicano Of Investigaciones Agropecuarias Y Forestales | Sandoval Sandoval Y.,Especialista Ambiental independiente | Demanet R.,University of the Frontier
Ciencia del Suelo | Year: 2012

In pasture systems, management practices can affect pasture productivity differently due to their impact on soil microorganisms and nutrient cycling. The objective of this study was to evaluate the relationship between soil microbial biomass (MB) nitrogen (MBN), carbon (MBC) and urease activity (UA) in a permanent pasture in southern Chile. Two grazing systems were evaluated between spring 2005 and winter 2006: heavy grazing (HG), light grazing (LG) and a control treatment (C). Treatments were arranged in a randomized block design with three replications. Concerning the average values of the variables measured at the beginning and at the end of grazing, there was an increase in the content of BC of 21.8 and 8.6% for HG and LG, while the control was only 1.9%. BN contents were also increased by 16 and 19% for HG and LG, respectively, compared with the control (4%). The urease activity increased by 13 and 27% for HG and LG, respectively, compared with the control (5%). Grazing produced a higher flow of organic residues in the soil, stimulating microbial biomass and therefore increasing the UA and the BC and BN content. Thus, soil biological fertility and nutrient availability s increase under grazing systems.


Beaver J.S.,University of Puerto Rico at Mayaguez | Rosas J.C.,Escuela Agricola Panamericana | Porch T.G.,Tropical Agriculture Research Station | Pastor-Corrales M.A.,U.S. Department of Agriculture | And 2 more authors.
Journal of Plant Registrations | Year: 2015

PR0806-80 (Reg. No. GP-296, PI 672994) and PR0806-81 (Reg. No. GP-297, PI 672995) are multiple disease-resistant dry bean (Phaseolus vulgaris L.) germplasm lines adapted to the humid tropics, developed and released cooperatively by the University of Puerto Rico Agricultural Experiment Station, the USDA–ARS, the Escuela Agrícola Panamericana (Zamorano), the Instituto Dominicano de Investigaciones Agropecuarias y Forestales, and the Ministry of Agriculture, Natural Resources and Rural Development of the Republic of Haiti. The breeding objective was to develop white dry bean lines that combine resistance to Bean common mosaic virus (BCMV), Bean common mosaic necrotic virus (BCMNV), Bean golden yellow mosaic virus (BGYMV), and rust, caused by Uromyces appendiculatus (Pers.) Unger. PR0806-80 and PR0806-81 were developed by pedigree selection to the F6 generation on the basis of superior agronomic traits, disease resistance, and commercial seed type. Advanced generation lines were screened for rust resistance in Honduras and were resistant to BGYMV, BCMNV, and rust in trials planted in Puerto Rico, the Dominican Republic, and Haiti. Results from greenhouse inoculations suggest that the lines combine the Ur-4, Ur-5, and Ur-11 alleles of rust resistance genes. Greenhouse inoculations were used to detect the presence of the bc-3 gene for resistance to BCMV and BCMNV, and marker-assisted selection was used to identify the presence of the bgm-1 allele and the SW12 quantitative trait locus for BGYMV resistance. The presence of SA14 and SI19 sequence characterized amplified region (SCAR) markers provided further evidence that these lines have the rust resistance genes Ur-4 and Ur-5. The lines were evaluated in field trials in the Dominican Republic, Haiti, and Puerto Rico. Mean seed yields of PR0806-80 (2048 kg ha-1) and PR0806-81 (2091 kg ha-1) were comparable to the check cultivar ‘Verano’ (2251 kg ha-1). These multiple disease-resistant white lines should be useful as parents to enhance the virus and rust resistance of white, small red, and black beans. © Crop Science Society of America. All rights reserved.


Torres S.V.,University of Puerto Rico at Mayaguez | Vargas M.M.,University of Puerto Rico at Mayaguez | Godoy-Lutz G.,Instituto Dominicano Of Investigaciones Agropecuarias Y Forestales | Porch T.G.,Tropical Agriculture Research Station | Beaver J.S.,University of Puerto Rico at San Juan
Plant Disease | Year: 2016

In common bean (Phaseolus vulgaris L.), Rhizoctonia solani Kühn is an important pathogen causing web blight (WB) in the tropics, and it is also a soilborne pathogen causing root rot (RR) worldwide. This pathogen is a species complex classified into 14 anastomosis groups (AG). AG 1-IA, AG 1-IB, AG 1-IE, AG 1-IF, AG 2-2, and AG 4 have been reported to cause WB of the aboveground structures of the plant, while AG 4 and AG 2-2 have been associated with RR. There is limited information, however, concerning the ability of particular isolates of specific AG to cause both diseases in common bean. Nine R. solani isolates, including three AG 1 and three AG 4 WB isolates and three AG 4 RR isolates collected from both leaves and roots, respectively, of common bean in Puerto Rico, were used to evaluate the response of 12 common bean genotypes to WB inoculated using a detached-leaf method and to RR inoculated using a solution suspension of R. solani mycelia in the greenhouse. All R. solani isolates were able to induce both RR and WB symptoms. RR readings were generally more severe than the WB readings. The RR isolate RR1 (AG 4) produced the most severe RR scores. A few bean lines had mean RR scores ≤4.4 for specific R. solani isolates on a scale of 1 to 9, with 1 representing resistant and 9 highly susceptible. However, all of the bean lines had mean RR scores ≥5.0 when inoculated with the isolates RR1, RR2, and RR3, which were determined to be AG 4 in this study. Significant line–isolate interactions were observed for the WB and RR inoculations for the three planting dates, suggesting a differential response of the common bean lines to the pathogen. This genotypic interaction may require bean breeders and pathologists to monitor the virulence patterns of R. solani in specific growing environments, while the compatibility of specific R. solani isolates to both aerial and root tissue needs to be considered for disease control strategies. © 2016 The American Phytopathological Society.


Prophete E.,REPUBLIC RESOURCES | Demosthenes G.,REPUBLIC RESOURCES | Godoy-Lutz G.,Instituto Dominicano Of Investigaciones Agropecuarias Y Forestales | Porch T.G.,Tropical Agriculture Research Station | Beaver J.S.,University of Puerto Rico at Mayaguez
Journal of Plant Registrations | Year: 2014

Bean golden yellow mosaic virus (BGYMV), Bean common mosaic virus (BCMV) and Bean common mosaic necrosis virus (BCMNV) are important diseases of dry bean (Phaseolus vulgaris L.) in Central America and the Caribbean. The development of dry bean cultivars with enhanced levels of resistance to these and other diseases is an important goal of the University of Puerto Rico (UPR) and other dry bean breeding programs in the Caribbean. PR0633-10 (Reg. No. GP-290, PI 668535) and PR0737-1 (Reg. No. GP-291, PI 668536) are multiple virus resistant bean germplasm lines adapted to the humid tropics that were developed and released cooperatively in 2013 by the UPR Agricultural Experiment Station, the USDA-ARS, the Instituto Dominicano de Investigaciones Agropecuarias y Forestales, and the Ministry of Agriculture, Natural Resources and Rural Development of the Republic of Haiti. Both lines have a red mottled seed type. PR0633-10 possesses the I and bc-3 loci that confer durable resistance to BCMV and BCMNV, whereas PR0737-1 only has the bc-3 locus that confers resistance to BCMV and BCMNV. Both lines have the bgm-1 gene for resistance to BGYMV, whereas PR0633-10 also has the SW12 quantitative trait locus associated with resistance to this virus. PR0633-10 and PR0737-1 produced mean seed yields as great or greater than check cultivars 'PC-50' and 'JB-178' in trials conducted in Puerto Rico, the Dominican Republic, and Haiti. Both lines should serve as useful sources of resistance to BGYMV, BCMV, and BCMNV. © Crop Science Society of America. All rights reserved.


Cruz-Hipolito H.,University of Cordoba, Spain | Rosario J.,Instituto Dominicano Of Investigaciones Agropecuarias Y Forestales | Ioli G.,University of Cordoba, Spain | Osuna M.D.,Research Center Finca la Orden Valdesequera | And 3 more authors.
Weed Science | Year: 2013

Tribenuron-methyl has been used widely fo. The last 15 yr to control white mustard in cereal crops from southern Spain. Since 2007, several cases of tribenuron-methyl resistance have been reported in wheat fields. Greenhouse and laboratory studies were conducted to characteriz. The mechanism of suspected tribenuron-methyl resistance in a white mustard biotype (hereafter AR16) from Malaga (southern Spain). Under greenhouse conditions. The dose (g ai ha -1) inhibiting fresh weight by 50% (ED50) was 5.20 and 0.57 fo. The AR16 and AR3 (known susceptible) biotypes, respectively. Wit. The use of 14C-tribenuron-methyl, absorption and translocation from treated leaves were similar between biotypes. Thin-layer chromatography indicated foliar metabolism of tribenuron-methyl was low in both R and S biotypes. Assays of the binding affinity of tribenuron-methyl on acetolactate synthase (ALS) revealed enzyme activity was reduced by 50% (I50 value) at 638.7 and 0.23 nM fo. The AR16 and AR3 biotypes, respectively. This resulted in 2,777-fold greater resistance to tribenuron-methyl fo. The AR16 compared to AR3 biotype. Sequencin. The gene encoding ALS, a proline/serine amino-acid substitution, was detected in position 197 of the A domain. Based on these results, it is concluded that tribenuron-methyl resistance I. The AR16 biotype is due to a target-site mutation I. The ALS enzyme, resulting in a lack of affinity to tribenuron-methyl. Nomenclature: White mustard, Sinapis alba L. © Weed Science Society of America.


Matos L.A.,University of Florida | Matos L.A.,Instituto Dominicano Of Investigaciones Agropecuarias Y Forestales | Hilf M.E.,U.S. Department of Agriculture | Chen J.,U.S. Department of Agriculture | Folimonova S.Y.,University of Florida
PLoS ONE | Year: 2013

Citrus greening (Huanglongbing, HLB) is one of the most destructive diseases of citrus worldwide. In South Asia HLB has been known for more than a century, while in Americas the disease was found relatively recently. HLB is associated with three species of 'Candidatus Liberibacter' among which 'Ca. Liberibacter asiaticus' (CLas) has most wide distribution. Recently, a number of studies identified different regions in the CLas genome with variable number of tandem repeats (VNTRs) that could be used for examination of CLas diversity. One of the objectives of the work presented here was to further validate the VNTR analysis-based approach by assessing the stability of these repeats upon multiplication of the pathogen in a host over an extended period of time and upon its passaging from a host to a host using CLas populations from Florida. Our results showed that the numbers of tandem repeats in the four loci tested display very distinguishable "signature profiles" for the two Florida-type CLas haplotype groups. Remarkably, the profiles do not change upon passage of the pathogen in citrus and psyllid hosts as well as after its presence within a host over a period of five years, suggesting that VNTR analysis-based approach represents a valid methodology for examination of the pathogen populations in various geographical regions. Interestingly, an extended analysis of CLas populations in different locations throughout Florida and in several countries in the Caribbean and Central America regions and in Mexico where the pathogen has been introduced recently demonstrated the dispersion of the same haplotypes of CLas. On the other hand, these CLas populations appeared to differ significantly from those obtained from locations where the disease has been present for a much longer time.


Valerio D.,Instituto Dominicano Of Investigaciones Agropecuarias Y Forestales | Garcia A.,University of Cordoba, Spain | Acero R.,University of Cordoba, Spain | Perea J.,University of Cordoba, Spain | And 2 more authors.
Archivos de Zootecnia | Year: 2010

The aim of this study was to analyze structural aspects of goat and ovine livestock farming systems located in the Norwest of Dominican Republic. The sample (94 farms) was randomly selected with proportional allocation by region. Forty-four variables related to structural and productive aspects were analyzed. The average size of farms was 96 ha and 165 animals. Their facilities are simple, nonspecific and barely functional, with a mean of 2 pens per farm. Farms generally do not have perimeter fences, facilities for breeding, feeding or watering points. The reproductive strategy is the natural breeding throughout the year on most farms, with a ratio of one sire for every 36 females, and there are no breeding records. The first mating takes place with an average weight of 17 kg at 6.5 months of age. Feeding is based on grazing of natural pastures and forests (94%), reaching a stocking density of 0.83 LU/ha. Food supplementation is used in 37% of farms, mainly in sheep and mixed farms. The lambs and goats are sold when they reach 23 kg in weight, around 7 months of age. The farms do not receive technical advice, although 94% of them apply preventive treatments on a regular basis. The mortality rate reached 12%. In general, farms are very heterogeneous in their production structure, management, nutrition and health. Thus, a group of farms developed a traditional system (goats), while the most efficient and technified correspond to sheep and mixed farms.


Espinoza P.A.S.,University of the Frontier | Fernandez J.A.G.,University of the Frontier | Ramos P.A.N.,Instituto Dominicano Of Investigaciones Agropecuarias Y Forestales
Ciencia del Suelo | Year: 2011

The fertilization efficiency program in pasture systems for improving livestock feeding is very important for for farmers in southern Chile. This paper reformulates a mathematical simulation model proposed to describe the concentration of total nitrogen (NT) in soil, in order to fit real experimental data. The objective was to determine the appropriate fertilization strategies in pastures and their direct use by livestock. Critical assumptions consisted, first, in that the concentration of TN in the soil depends on the concentration of its three major components: organic nitrogen (N-NO), nitrate nitrogen (N-NO3-) and ammonium nitrogen (N-NH4+) and second, that the behavior of the concentration of these components depends strongly on the season of the year and, therefore, the coefficients in the model must be different for each season and third, that only the first 10 cm of the soil profile are meaningful for pasture growth. The modified model consists of a system of partial differential equations (PDE), which consists of EDP's for N-NO and N-NO3-, while N-NH4+ was interpolated by a polynomial with the degree varying with the season. The model parameters were calculated solving a functional least squares sum of residuals, using the experimental data. We used optimization methods to solve the problem of least squares. The model used initial data and boundaries approximated by polynomials for each season of the year. The resulting parameters were two: A Quasi-Newton (BFGS) and a Genetic Algorithm (GA). The combination of these algorithms was used to avoid possible local minima and to find a global minimum. The GA was used systematically to find good reference points, which gave BFGS as the initial solution. This combination worked well as all the parameters found globally minimized the residual sum of squares. The results showed that the proposed model was significantly adapted to the data (with a 3% maximum error); therefore, the parameters obtained can be considered for the model for the soil type and season accordingly. © 2012 Asociación Argentina de la Ciencia del Suelo.


Marte W.E.,Kyushu University | Marte W.E.,Instituto Dominicano Of Investigaciones Agropecuarias Y Forestales | Nanseki T.,Kyushu University | Takeuchi S.,Kyushu University
Journal of the Faculty of Agriculture, Kyushu University | Year: 2012

Rice is the main staple food crop in the Dominican Republic (DR). Although 45% of the rice farmers hold less than 4 ha, rice plays a significant role in food security and provision of employments. However, the process of trade liberalisation given by the Dominican Republic, Central America and the United States of America free trade agreement (DR-CAFTA) questions the viability of Dominican rice farming. Besides, the US rice farmers have larger farms, better access to technology and credit and higher yield compared to those in the DR. This calls for sound management strategies and policies to overcome some of the forthcoming effects of the DR-CAFTA on the Dominican rice farming. Thus, this study identifies and evaluates the Dominican rice farmers' agronomic and economic strategies on this FTA. The analysis used cross-sectional survey data collected from 93 rice farmers in Monte Cristi province. The results indicate that to reduce rice-production costs, self-financing, and expanding farmland size were the main agronomic strategies. While land levelling, buying certified seeds, and increasing yield were the main economic strategies. The evaluation of these strategies revealed that fertilizer, machinery service costs and paid interest on operating capital were key components to reduce rice-production costs. Further, results indicate increasing returns to scale for rice farmers. To undertake such strategies, the transformation of farmers' association to a cooperative is a promising strategy from farmers' side.

Loading Instituto Dominicano Of Investigaciones Agropecuarias Y Forestales collaborators
Loading Instituto Dominicano Of Investigaciones Agropecuarias Y Forestales collaborators