Centro Agrícola

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.