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Introduction. In recent years, significant results have been obtained in Cuba in the joint management of efficient strains of arbuscular mycorrhizal fungi (AMF) and Canavalia ensiformis L., in different types of soils. However, there are no reports about the effectiveness of strains of AMF in Calcaric Histosol soils, which are highly represented in the central and eastern areas of the country. Objective. The objective of this research was to compare the effectiveness of four AMF strains inoculated in C. ensiformis seeds in in Calcaric Histosol soils. Materials and methods. Plants through seed coatings inoculated and a non-inoculated control were evaluated; C. ensiformis L. was used as plant host in a complete randomized design with four repetitions per treatment during two consecutive years. Sixty days after C. ensiformis seeding, the biomass production; N, P and K contents; percentage of total mycorrhizal colonization; and the reproduction of mycorrhizal spores were evaluated. Results. For all variables, there was a positive and differentiated response between the different strains, and the highest values (p≤0.05) were obtained with the inoculation of Rhizoglomus intraradices / INCAM-11. The high amounts of spores produced by the inoculation with R. intraradices / INCAM-11 were indicative of to the possibilities of using Jackbean as a way to introduce efficient strains in this edaphic condition. Conclusion. The results obtained allow to include Calcaric Histosol soils, with pH>7.5, in the group of soils in which R. intraradices / INCAM-11 behaves as an efficient strain.

En la Unidad Científico Tecnológica de Base Los Palacios, Cuba, a 22° 34’ 32.73’’ N y 83° 14’ 11.95’’ O, se evaluó el efecto de la inundación sobre la colonización de hongos micorrízicos ar-busculares durante la fase vegetativa de plantas de arroz cultivar INCA LP-5.  Se realizaron dos experimentos en condiciones de invernadero en macetas con una capacidad de 800 g de suelo, ambos experimentos en un diseño experimental completamente aleatorizado.  Uno de ellos se realizó con Rhizophagus (=Glomus) intraradices (Ri), donde se evaluó la dinámica de colonización de la simbiosis micorrízica en condiciones de inundación y secano (no inundadas).  En el segun-do experimento se trabajó con Glomus cubense (Gcb) y se evaluó la colonización micorrízica en plantas de arroz cultivadas con diferentes alturas de lámina de agua.  En ambos experimentos se evaluaron altura de la planta, producción de masa seca y tasa absoluta de crecimiento.  Co-mo resultado se encontró que las plantas de arroz fueron colonizadas a partir del día 35 después de la germinación, tanto en condiciones inundadas como no inundadas, con una tendencia al incremento en el tiempo.  Se comprobó que la colonización micorrízica disminuyó en condiciones de inundación y a medida que la altura de la lámina de agua fue superior se encontraron valo-res inferiores de este indicador.  La colonización micorrízica incrementó el desarrollo de las plan-tas de arroz<div id="__if72ru4sdfsdfrkjahiuyi_once" style="display: none;"> </div><div id="__zsc_once"> </div><div id="__if72ru4sdfsdfruh7fewui_once" style="display: none;"> </div><div id="__hggasdgjhsagd_once" style="display: none;"> </div>

To evaluate the foliar application of the Quitomax® biostimulant in Cucumis sativus crop, an experiment was developed at the municipality of Pinar del Río province, Cuba, under protected crop conditions. The treatments consisted in applying 300 and 500 mg.ha-1 10 and 25 days after transplantation (ddt) and a commercial Bayfolan Forte® control. A randomized design with four long replicates was used and variables such as height and thickness of the plant stem of Cucumis sativus, number of total fruits, fruit mass and number of exportable quality fruits were measured during five harvest times (32, 39, 46, 60 and 67 ddt). The results showed that the higher concentration of Quitomax® applied (500 mg.ha-1) in the two growth moments produces the highest values for the growth variables and the highest exportable quality fruits.

The experiment was carried out with the objective of evaluating the biostimulating and nematicidal effect of Trichoderma harzianum Rifai "strain A-34" and aqueous extract of Azadirachta indica A. Juss. (neem) in Solanum lycopersicum L. (tomato) cv. "PR-92". Two trials were developed, the first in the seed germination process and the second in potting conditions for the treatments interaction and the inoculation of Meloidogyne spp. with tomato seedlings. The results showed that tomato seeds cv. "PR-92" treated with T. harzianum "A-34" and aqueous extract of neem leaves did not affect the percentages of germination, however, the combined use of the preparations promote the seedlings growth. It was also corroborated that the seedlings infested with Meloiodgyne spp. showed lower means for stem length, total fresh mass and dry mass variables, compared to non-infested ones. As for the regulation of Meloidogyne spp., a reduction of the gill index was achieved in 53.5%, 38.5% and 61.5% for treatments where T. harzianum, neem and their combination were respectively applied with significant differences respect to control.

Introduction. The water deficit negatively affects rice plants and limits their productivity. Arbuscular mycorrhizal symbiosis has been shown to improve rice productivity in drought conditions. Objective. To propose a new categorization for the state of water stress of rice plants inoculated (AM) or not with arbuscular mycorrhizal fungi (nonAM) and exposed to water deficit (D) during the vegetative phase. Materials and methods. The experiment was carried out under controlled greenhouse conditions during the years 2009 and 2010 at the Zaidín Experimental Station, Granada, Spain. The rice transplantation was carried out fourteen days after germination to pots with a 5 cm water sheet and at 30, 40, or 50 days after transplantation (DAT) they were subjected to water deficit during a period of 15 days, at which time the water sheet was restored. The control treatment was maintained throughout the cycle under flood conditions (ww). Evaluations were performed at 45, 55, 65 DAT and after recovery at 122 DAT. The harvest was carried out at 147 DAT. Results. The reduction in water supply demonstrated water stress in the plants, manifested by the decrease in the water potential of the leaves. Arbuscular mycorrhizal symbiosis always favored the water status of the plant. Four categories of water status of plants were proposed taking into account water potentials and agricultural yield: no stress (≥-0.67 MPa); light stress (<-0.67 to -1.20 MPa); moderate stress (<-1.20 to -1.60 MPa), and severe stress (<-1.60 MPa). Conclusion. The categorization of stress due to the water deficit is a tool of high scientific value for the specific case of rice, since this plant has the capacity to adapt to tolerate the presence of a sheet of water throughout its biological cycle and is highly susceptible to water deficit.

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