Centro Agrícola

5-11

Authors: William Castro López, Karina Carrera Sanchez, Felipe Lidcay Herrera Isla, Rene Cupull Santana

The vascular wilt is the most destructive disease of naranjilla (Solanum quitoense Lam) in the ecuatorian Amazon causing field losses near 80 %. In this study was identified and characterized some isolates at a fungus belonging to the genus Fusarium associated with this disease. Eight isolates of Fusarium spp. were obtained from plants with symptoms of wilt from representative areas cultivated with naranjilla, Pastaza province. Each isolates were cultivated in Petri dishes (90 mm Ø) contained PDA and CLA media. The cultural parameters evaluated were: colour of the colony (reverse and obverse); mycelia texture; mycelial grown and others morphological characters like: size of conidia (length and width) and chlamydospore size. Several taxonomical keys were used to identify the fungi isolated. A randomized design was utilized and the data were processed statistically by means IBM-SPSS Statistics version 23 on Window. The eight isolates belonging to the genus Fusariumspp. a fungus reported for several authors as the causal agent of the wilt in this plant.

20-26

Authors: Wilfredo Estrada Prado, Licet Chávez Suárez, Eduardo Jerez Mompie, María Caridad Nápoles García, Yariuska Caridad Maceo Ramos, Cristóbal Cordoví Domínguez

The effect of Azofert® on bean plants on the relative water content and the pigments concentration under two irrigation regimes was evaluated. The experiment was carried out in the light room of the Department of Plant Physiology and Biochemistry of the National Institute of Agricultural Sciences, San José de las Lajas, Mayabeque. The varieties CC-25-9R and Tomeguín-93 were used. In each case, Azofert® was applied, with a dose of 200 mL per 50 kg of seed at the time of sowing and as controls were used treatments without the application of this product. The irrigation treatments consisted of applying 100 and 50 % of the maximum moisture retention capacity. A completely randomized design was used. Ten plants were selected at random for each treatment to evaluate fresh leaf mass, saturated mass, fresh leaf mass, relative water content and concentration of photosynthetic pigments. The results showed that the bean plants are affected when subjected to a soil moisture deficit and the inoculation with Azofert® was able to attenuate the effects of water deficiency. The relative water content decreased significantly in both varieties when humidity is reduced. The chlorophyll b content was affected in both varieties when subjected to water stress conditions. The content of carotenoids in the CC-25-9R variety had a significant increase in water stress conditions.

34-42

Authors: Ariany Colás – Sánchez, Beatriz Díaz – Pérez, Alianny Rodríguez-Urrutia, Sirley Gatorno-Muñóz

Common bean (Phaseolus vulgaris L.) is widely cultivated in Cuba principally in small farm areas because its role as a principal component of the daily diet. The use of effective native rhizobia as natural biofertilizer will positive contributes to the production of this grain. In order to evaluate the effect of single Rhizobium pisi and EcoMic® inoculation on morphological parameters and yield of common bean, was performed the present research at the intermediate sowing season of the 2015-2016 (November - January). The study was developed in farm´s areas of CCS "Lino del Rio" under an Inceptisol soil in the municipality of Placetas in Villa Clara province. In the study, the genotype Delicia-364 was used and the parameters of nodulation, root and shoot biomass and yield were evaluated, as well as the possible mechanisms of plant growth promotion of the strains used. All the inoculation variants increased the nodulation and, consequently, the dry biomass. The maximum values in the number of nodules were observed with the inoculation of R. pisi 40983. The yield and its components were positively stimulated with the inoculation of R. pisi 40983 (362 kg ha-1) and 40982 (357 kg ha-1).

49-58

Authors: Romney Marconi Mora Erraez, Carlos Valarezo Manosalva

The research was realized at "Los Zapotes" site, "Panguintza" parish, "Centinela del Cóndor" canton of "Zamora Chinchipe" province, with the objective of generating alternatives for commercial reforestation of the degraded areas by the effect of cattle raising. The arrangement of the experiment was in subdivided plots (2x2x3) distributed in random blocks, with three repetitions and twelve treatments that correspond to the combination of three factors: a) two arboreal species: Gmelina arborea Roxb. ex Sm. and Schizolobium parahyba (Vell.) S.F. Blak; b) without and with fertilization. After two years the fertilization determined significant differences in the variables height, basal diameter and diameter of chest height in the two species. The applications of 3 and 6 t ha-1 of vegetal coal did not have effects on the growth of arboreal species. In all treatments the aerial biomass of Melina was higher than the Pachaco. There was also higher accumulation of carbon in the soil and in the biomass in the treatments applied to the Melina.

68-74

Authors: Carlos Osvaldo Romero Romano, Juventino Ocampo Mendoza, Engelberto Sandoval Castro, José Refugio Tobar Reyes

The objective of this research was to evaluate the droppings of bovine and ovine and the peanut shell (Arachis hypogaea L.) as a substrate to produce Eisenia foetida Sav. earthworm. The experimental design was randomized blocks with three replicates and seven treatments: peanut shell, bovine droppings, ovine droppings, and combinations of them. The variables analyzed were population of young worms (without clitellum), adults (with clitellum) and total population. The substrates were deposited in 0.72 m3 wooden crates and pre-composted. When the temperature of the substrates was in the range of 23-25 ° C and the humidity between 75-80 %, 50 earthworms were inoculated per box. Sixteen counts were made (one per week), using a PVC tube (40 cm long and 10.16 cm diameter). In each count eight samples of substrate were taken for each of the treatments and their repetitions, following a zigzag pattern. Significant differences (Tukey, p< 0.05 %) were obtained by treatment in the three variables. The mixture "peanut shell-sheep droppings-bovine droppings" recorded the highest number of young worms (113.29). The combination "peanut peel -bovine droppings", as well as "bovine droppings alone", showed the largest population of adult earthworms (98.94 and 94.89). The total population was greater in the treatments "peanut peel-bovine droppings" and "peanut peel-sheep droppings-bovine droppings" (196.50 and 197.33). It was concluded that the combination of bovine droppings with peanut shell is a suitable substrate for earthworm production.

85-90

Authors: Amaurys Dávila Martínez, Lidcay Herrera Isla, Maryluz Folgueras Montiel, Dahert García Hernández

Papaya crop (Carica papaya L.) faces pathologies mainly of fungal etiology. Colletotrichum gloeosporioides (Penz.) Sacc., causal agent of anthracnose, represents one of the most severe diseases that reduce the productivity of plantations. For this reason, the present study was carried out on one hectare of papaya cultivar 'Maradol Roja' at the Research Institute of Tropical Root and Tuber Crops (INIVIT), with the objective of evaluating the technical effectiveness of the fungicide Sphere Max 535 SC (trifloxystrobin + ciproconazole) for the control of anthracnose at doses of 0.2 and 0.3 L ha-1 and Biobeno (Benomilo), the latter as a commercial reference. A completely randomized design was used; five applications were made with a frequency of 20 days. The severity of the disease was evaluated, as well as the technical effectiveness of the formulations used. The severity increased gradually, reaching its maximum values at 100 days. In the plots treated with Benomilo, the severity of the disease was higher, reaching an average of 22.3 %. The variants corresponding to Sphere Max 535 SC were more effective than Benomilo, with values of 57,8 and 61,5 % of effectiveness, respectively.

5-10

Authors: Elio Minel Del Pozo Núñez, Irma García Cruz, Yanira Herrera López

The present project was developed in the Plant Protection Laboratory of the Agronomy Faculty of the Agrarian University of La Habana, Cuba, to determinate the in vitro effectivity of some isolates of Beauveria bassiana sensu lato (Vals.) Vuill. on eggs and neolarvae of Rhipicephalus microplus Canestrini. The three isolates evaluated were effective, with more than 85 % mortality over neolarvae of the ectoparasite, 12 days after application. In the case of the BB isolate a b effect of the conidia concentration in the suspension over the eclosion of eggs was evident, wich was null in the highest of the concentrations used, and the mortality of tick neolarvae, that was superior to 90 % with concentrations over 107 conidia mL-1.

17-26

Authors: Yurelkys Fernández Maura, Philippe Lachenaud, Cony Decock, Amauri Díaz Rodríguez y Noryaisi Abreu Romero

Black pod is one of the major like-fungal diseases of Theobroma cacao L. in all its cultivation areas. It is caused by several species of Phytophthora. In Latin America, the etiological agents of the black pod disease are more likely diverse and, in a taxonomic perspective, incompletely known, especially in small producing countries, such as Cuba and French Guiana. In the present work, we studied two sets of Phytophthora strains isolated from diseased pods and originating from Cuba and French Guiana, combining morphological, biological and molecular approaches to identify the species involved. Phylogenetic analyses were performed based on DNA sequence data from two loci, ribosomal internal transcribed spacer and partial ß-tubulin. Two species were identified in Cuba, P. palmivora and P. tropicalis, and two species in French Guiana, P. tropicalis / capsici complex and a potential novel Phytophthora sp. In Cuba, P. palmivora was by far the dominant species (98% of the isolates) and the strains studied belonged to the Mating Type A2 (88 out of 90 isolates). In French Guiana, P. tropicalis / capsici complex was the dominant species in our sampling (7 out of 8 isolates).

32-36

Authors: Emma Pineda Ruiz, Fidel Acosta Hernández(†), Irenaldo Fernández Denis, Dunia Núñez Jaramillo, Ana Rosa Hernández Freires, Osmany de la C. Aday Díaz, Zenaida Occeguera Águila, Pablo Machado Armas, Mayra Jiménez Vázquez, Edel Toledo Rodriguez y Rafael Más Martínez

The substrate used in the phase of acclimatization is determinant to reach quality plants. They can be solid and porous materials of natural or synthetic origin that alone or mixture guarantee a suitable growth of the plants under environmental controlled conditions. The aim of this work takes root in the evaluation of three variants of substrate for this phase: 80 % of compost and 20 % of zeolite (I); 50 % of the treatment I more 50 % of solid residue obtained of the biogas from vinaza (II) and 100 % of the solid residue of the biogas (III). There was characterized the chemical composition of the substrate. The following evaluations were made: survival, number of dead plants and number of leaves, to the last evaluation were added: root length, stem height and diameter, leaf length +1, number of total leaves, pests and diseases present. The solid residue of the biogas formed from vinaza, presented a top content of organic matter and total macroelements. This residue allows the growth of the in vitro plants and is feasible to use it as substrate only or mixed with the compost.

44-50

Authors: Segundo Ramiro Mora Quilismal, Edith Aguila Alcantara, Yanetsy Ruiz González, Luis Rodrigo Balarezo Urresta, Hernán Rigoberto Benavides Rosales

The goal of this research was to assess alternatives of biofertilization with Fosfotic, Safer-mycorrhiza, and their combination in the potato variety Superchola under semi-controlled conditions. The experiment was carried out in a greenhouse and the substrate used was a typical Andisol of the region. A Completely Randomized Design was used with three replications. These alternatives and their combinations with the NPK dose that is used in the region and with different reductions of it, were evaluated, forming a total of 23 treatments. The best integral results were obtained with the treatments in which mineral fertilization is combined with some of the biofertilization alternatives (Fosfotic and Safer-mycorrhizas), with which it is suggested that these studies be continued under field conditions in the Andisols of Carchi -Ecuador. It is demonstrated that both the inoculations with Fosfotic and Safer-mycorrhizas, as well as their joint inoculation, can constitute viable alternatives in the cultivation of potatoes in these soils. However, the reduction of the mineral fertilizers without combine that with biofetilizers implies a reduction of the production, so it is not recommendable.

59-65

Authors: Iliana Fernández Santana y Lázaro Jesús Ojeda Quintana

The living collections of the Cienfuegos Botanical Garden store a wealth of vascular plants with an average of 70 years. A great concern for the specialists at the botanical garden is that many of the species are represented in the collections by a single individual. In 1998, a program was developed to preserve these species. This program implies the control of its reproduction, cultural management and the monitoring of insect pests and diseases. Starting from the detection of Paratachardina pseudolobata Kondo & Gullan (Hemiptera: Coccoidea: Kerriidae) in 2008, the present investigation was conceived with the objective of identifying it's host plants and the level of infestation. The presence of the insect was verified in 36 % of the species, 39 % of the genera and 90 % of the botanical families present at the Cienfuegos Botanical Garden. It was found that 12.8 % of the specimens conforming the collection of living plant were affected. Urgent control measures were undertaken to control the insect pest and to avoid its proliferation. The 6 % of the plants presented severe infestation, 25 % average infestation and 69 % light. Of the affected species, 256 constituted new host plant registers for P. pseudolobata in Cuba, including four families (Dichapetalaceae, Juglandaceae, Bignoniaceae and Cupressaceae), nine Cuban endemic and 12 native species, of them, six species with threat category.

73-80

Authors: Elieni Quintero Rodríguez, Alexander Calero Hurtado, Yanery Pérez Díaz, Lorettys Enríquez Gómez

With the objective of to evaluate the effect of different biostimulants in the increase of morphophysiological and productive indicators of common bean, the following research was carried out at the collective farmer "Joe Westbrook" in Sancti Spíritus, Cuba, from November 2014 to February 2015. The sowing of cv. Bat-304 was carried out manually form at a distance of 0.80 m between rows and 0.15 m between plants. The following treatments were evaluated: Efficient Microorganisms (ME-50), ME-Agitado and LEBAME, Fitomas E, Biobras-16® and a control (without application). The evaluated variables were: plant height, stem diameter, number of leaves per plant, dry matter, grains per pod, mass of 100 grains and yield. The results showed that the foliar application of the different biostimulants increased the morphophysiological and yield indicators evaluated. The highest yields when biostimulants ME-50 and Biobras-16® were applied, with 2.01 and 2.00 t ha-1 respectively.

88-91

Authors: Fernando Franco Flores, Pavel Oriol Rodríguez Vázquez, Pedro Pablo Herrera Oliver, Alicia Leiseca Pérezy Rosalina Berazaín Iturralde

This paper presents the main results of the rescue of the historical collection (series HEA) of the herbarium of the then School of Agronomy from the institutionalization of the Herbarium of the Faculty of Agronomy (HFA), Agrarian University of Havana.

5-11

Authors: Miriam Díaz-Díaz, Danieyis Sánchez Hurtado de Mendoza, René Cupull Santana, Alexander Bernal Cabrera, Ricardo Medina Marrero, Miriam Carballo Bargos, Milagros García Bernal y Mayra Acosta-Suárez

The effect of seed treatment with the actinomycetes strains EA2 and CB14, and their combination, on damping–off incidence caused by Rhizoctonia solani Kühn in Phaseolus vulgaris L. cv. Velasco largo was evaluated under greenhouse conditions. These strains were compared with Trichoderma harzianum A-34, Celest®Top 312 FS and two controls (positive and negative). Inceptisol sterile and non-sterile soil was used under a completely randomized design. The coating seeds with strains were made using 8 % cassava starch. The incidence of R. solani was determined 21 days after sowing. In non-sterile soil, the lowest incidences caused by R. solani were found with Celest®Top 312 FS, which did not significantly differ from the combination of actinomycete strains CB14 + EA2, but yes with the rest of the treatments. In the sterile soil, the lowest percentages of incidences were obtained with the combination of actinomycete strains (CB14 + EA2).

21-28

Authors: Yarisbel Gómez Masjuan, Tony Boicet Fabre, Norge Tornés Olivera, y Yanitza Meriño Hernández

The investigation was carried out in four localities of Granma province, Cuba. The objective was to evaluate the magnitude of the genotype-environment interactions and adaptation of tomato varieties in different locations affected by drought through performance stability parameters. A combined analysis of variance for the main effects of genotype and environment was performed, and a principal component analysis for non-additive effects of the interaction. This analysis called the Principal Additive Effects and Multiplicative Interaction Model is constituted by additive and multiplicative parameters. It was analyzed by MATMODEL program. Genotype-environment interaction expressed the ability varieties to fit a particular environment. The varieties Amalia and Vyta presented the highest adaptability and the highest yields (30.26 and 24.84 t ha-1 respectively).

34-39

Authors: Elio Lescay Batista, Yadira Vázquez Ramírez y Fernando Celeiro Rodríguez

The research was developed in the rainy season, on a Fluvisol soil, belonging to the Credit and Services Cooperative "Rubén Nogueras Castillo", Cauto Cristo municipality, Granma, to determine the phenological characteristics and agricultural yield of five soybean cultivars. Seeding was performed on individual rows 5 m long and the design was a randomized block with three replicates. Planting distance used was 0.70 x 0.05 to 0.07 m. A double classification variances analysis and multiple means comparison were performed with the Tukey test. The vegetative phase, up to the eighth node, showed a similar behavior in the cultivars evaluated with values that oscillated between 38 and 40 days after sowing. Reproductive phase lasted 50 to 56 days, highlighting the cultivars INCASOY-36 and Foscarini as the earliest, FT-2 reached the highest agricultural yields with 2.2 t ha-1.

47-54

Authors: Joaquín Montalván Delgado, Isabel Alfonso Terry, Eida Rodríguez Lema, Yaquelín Puchades Izaguirre, José Rodríguez Zayas, Osmany Aday Díaz, Omelio Carvajal Jaime y Javier Delgado Padrón

In Cuba, the methodology used for the evaluation of resistance to sugarcane brown rust (Puccinia melanocephala Sydow and P. Sydow) lacks quantitative aspects, as well as the definition of representative localities for resistance tests and has limited patterning. In order to establish new evaluation criteria that contribute to the improvement of the Evaluative System of the Resistance to the brown rust in the Program of Improvement of the Sugar Cane in Cuba, during the 2007 – 2015, six patterns of known reaction and 11 commercial cultivars were study in 6 localities. The variables length, quantity and percentage of leaf area occupied by pustules and length of the major pustule were recorded. The six localities of resistance test were ratified and the evaluations must be carried out in the middle third of the leave +3 of ten plants at three and five months of age, with an evaluation scale with new quantitative criteria (area occupied by pustules and length of the major pustule). Cultivars SP70-1284, C88-380 and C323-68 are included as standards. C334-64, Ja60-5 and B4362 are reclassified. The methodology for evaluating the brown rust of sugarcane in Cuba is modified and a new scale of evaluation of the disease is proposed.

61-68

Authors: Osmany de la Caridad Aday Díaz, Eida Rodríguez Lema, Joaquín Montalván Delgado, Einar Martínez de la Parte e Isabel Alfonso Terry

Sugarcane orange rust (Puccinia kuehnii (W. Krüger) E.J. Butler) is considered an emerging disease in the Western Hemisphere and with high potential for damage. It was detected in Cuba in late 2008, which is why phytosanitary surveillance was established on its dispersion and incidence in the sugarcane plantations of the country. The objective of this work was to update the status of this disease in Cuba from the processing of data from research and surveys conducted in the period 2009-2017. Evaluations were carried out in the risk areas through systematic sampling in germplasm banks, varieties gardens, experimental areas and seed banks, including those established from "in vitro" plants. In addition, surveys were carried out in areas of commercial plantations, validation areas of new cultivars and areas of certified seed production, where 10 stems were randomly evaluated in three sampling stations following the diagonal of the field. P. kuehnii is found in the 13 provinces producing sugarcane in Cuba. Most infected genotypes were found in areas of experimental stations, mainly in the provinces of Mayabeque, Villa Clara and Camagüey. The distribution of this pathogen in the national territory is classified as low prevalence; however, the number of infected commercial cultivars rises to 30.

77-82

Authors: Diana González Aguiar, Ubaldo Álvarez Hernández, Raciel Lima Orozco

With the objective to assess the fresh biomass and dry matter accumulation per plant in cowpea – sorghum intercropping, a field experiment was carried out in the farm of self-consumption "Día y Noche", at the Basic Unit of Cooperative Production "28 de Octubre", Santa Clara municipality, Villa Clara province, Cuba, on a Cambisol soil. The two spatial arrangements consisted on one sorghum row and two cowpea rows; one sorghum row and three cowpea rows. Also, the respective cowpea and sorghum monocultures were evaluated. For determining fresh biomass and dry matter accumulation per plant, 15 plants per treatment were harvested. The maximum values in fresh biomass and dry matter accumulation were observed in one sorghum row and two cowpea, and sorghum monoculture treatments, with 227 g, 47 g for cowpea and 241.4 g, 110 g for sorghum respectively.

5-13

Authors: Dagoberto Guillén Sánchez, Ricardo Hernández Perez, María Andrade Rodríguez, Víctor López Martínez, Irán Alia Tejacal y Porfirio Juárez López

The efficacy of six fungicides for the control greasy spot (Mycosphaerella citri Whiteside) in orange (Citrus sinensis (L.) Osbeck) cv 'Valencia' was evaluated in plots with a randomized block design and six treatments: Azoxystrobin + Difenoconazole, Flutriafol, Difenoconazole, Benomyl, Copper Oxychloride, Trifloxyistrobin and a control. Three spraying, were made, every fifteen days. During the experiment, the incidence, severity and efficacy in the control of (M.citri) were evaluated. In addition, area under the disease-progress curve (AUDPC) and disease-progress curve relative in percent (AUDPCr) were calculated. The data were processed through a simple ANOVA. As results, the incidence remained unchanged up to 21 days after treatment (DAT), with low values between 1.3 and 5 %, which increased from 28 DAT (58-96 %). The initially severity was low (0.1-3 %) and was increased up to 32 %. The efficacy 7 DAT had the highest percentages with Benomyl and Trifloxyistrobin (87.5 %) and Difenoconazole (75 %). While at 14 DAT Difenoconazole and Azoxydifem reached 87.5 %. All fungicides reduced the area under the disease-progress curve (AUDPC) in relation to the control and in correspondence the lowest cumulative relative percentages of disease-progress curve relative in percent (AUDPCr) were obtained by Flutriafol, Benomyl and Trifloxystrobin (8.4, 8.6 and 8.7 %), although without statistical differences with other fungicide, only with the control (11.2 %).

24-33

Authors: Héctor Jorge Suárez, Antonio Menéndez Sierra, Alberto González Marrero, Irenaldo Delgado Mora y José Ramón Gómez Pérez

Knowledge and classification of the different test sites and their evaluation for the study of the genotypes becomes obligatory, in the breeding programs, also the knowledge of the adaptability of the cultivars allows to maximize their production. The objective of the work was to determine the adaptability and phenotypic stability of new cultivars introduced in CALESA by means of the Two-dimensional Representation method (Biplot), in two crops, as well as recommending those with the best agroproductive behavior under soil and climate conditions, of the Ingenio Ofelina. Twenty cultivars were planted in red Ferralitic, Brown without carbonate and Ferralitic quartzitic soils.The crop variables studied were: cane yield, pol yield and percentage of pol in cane. The environmental effect and the genotype-environment interaction were superior to that of the genotypes in the contribution to the total phenotypic variation. The cultivars E07-04, E07-09, BT84102 and Na56-42 in the three agrosugar characters were stable and adapted to the different environmental conditions and showed a sugar content similar or superior to the controls. The main component's analysis offered the formation of six different groups which correspond to the environments evaluated, there being a small approach between environment 2 and 4.

40-46

Authors: Carlos Alberto Sangoquiza Caiza, Yosvel Viera Tamayo y Carlos Fernando Yánez Guzmán

Azospirillum is one of the most studied free-living rhizobacteria currently of great agricultural interest because of its ability to bind biological nitrogen and produce phytohormones. The present research aimed at the biological response of Azospirillum spp. facing different types of stress. For this purpose, the micro and macro morphological characterization of Azospirillum spp. And its biological response to stress temperature, pH, salinity. The results revealed that the isolates (C2, C3 and C4) of Azospirillum spp. Grow in greater abundance at temperatures between 28-38 °C and pH between 7-8. The C2 and C3 isolates showed good growth up to 3.5 % (m / v) NaCl, whereas the C4 strain was less tolerant. These results have biotechnological applicability and are of great importance when defining and controlling the mass production conditions of Azospirillum spp. for future formulations as biofertilizer in several crops of interest in Ecuador.

52-61

Authors: Enildo Abreu Cruz, Evencio Araujo Camacho, Sergio Luis Rodríguez Jimenez, Aymara Luisa Valdivia Ávila, Leticia Fuentes Alfonso y Yunel Pérez Hernández

The aim of the present work was to evaluate the effect of different doses of chemical fertilizer and worm humus, on growth and development of Capsicum annuum L. cv. Magistral. As chemical fertilizer was used the 10-20-10 formulation and as organic fertilizer the earthworm humus was used. Five treatments were applied: chemical fertilization 100 %, 2, 4 and 6 t ha-1 of humus + chemical fertilization (75 %) and 4 t ha-1 of humus only. Different indicators of growth, reproductive and crop yields were evaluated. The data were analyzed by variance of simple classification and Tukey Test was used for comparison among media of treatments. The best results were obtained with the application of chemical fertilizer 100 % in the first harvest in relation to height, number of leaves, flowers, fruits per plants and fruit weigh. The effect of humus application combined with chemical fertilizer improved the reproductive parameter in the second harvest. The yield obtained was higher with the application of chemical fertilizer in the first harvest; however in the second harvest the results achieved were similar to that the yield after the application of chemical fertilizer 75 % + humus 4 and 6 t ha-1, which showed the positive effect of humus on the parameter evaluated. The results obtained showed the potentiality of the worm humus to reduce the application of chemical fertilizer without affecting yield of C. annuum.

69-77

Authors: Alexei Yoán Martínez Robaina, José Manuel Febles González, Nelson Moura do Amaral Sobrinho, Mileisys Benítez Odio, Mariol Morejón García, Michel Ruíz Sánchez y Ramón Hernández Carballo

The tobacco constitutes an important source of income to the Pinar del Río province. However, production technologies have contributed to the degradation of soils; crop alternating is one of the effective measures to mitigate this effect. The objective of the investigation was to evaluate the incidence of different variants of alternation in some chemical and physic - chemical properties of the soil. The work was developed in areas dedicated to the tobacco crop, the variants of alternation evaluated were uncultivated soil, tobacco - fallow, tobacco - corn and tobacco - polycultures. In the selected areas, 96 samples were collected at depths of 20 cm and 40 cm and 40 producers were surveyed. Descriptive statistical methods were applied to compare the means in each variant of land use. The results showed that the predominant pH was slightly acidic, the tobacco-fallow variant showed values close to neutrality. The content of organic matter did not exceed 1% in the variants of cultivated soils inferior to those not cultivated, changeable bases and cation exchange capacity were similar in the cultivated soils, and the calcium showed the highest values in tobacco-fallow. It is concluded that the different land use variants did not have a marked effect on the pH values. The content of soluble phosphorus increased in all the variants of cultivated soils. The alternation of crops, as the only measure of improvement, does not guarantee an improvement in the chemical and physic - chemical properties of the soils.

88-91

Authors: Armando del Busto Concepción, Yoerlandy Santana Baños, Francisco González Breijo, Jorge Domínguez García, Yosbel López Quintana, Maikel Díaz Barrio, Yandelier Hidalgo Valdés, Javier Enrique Cabrera Rodríguez

The objective of this project was to: evaluate the productive response of six cucumber hybrids in the cultivation houses of the "Enrique Troncoso" Citrus company.