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La variedad IACuba-37 fue obtenida a partir del cruzamiento, IACuba-16//J104/2064; después de obtenida la población producto de dicho cruzamiento, fue conducida por el método masal modificado hasta llevarla a la homocigosis, se obtuvo entre varias línea, la 4544, la que fue estudiada en los ensayos de rendimiento de todo el País y por sus resultados, resultó aprobada como nueva variedad de arroz para las condiciones de riego por el Instituto de Investigaciones de Granos de Cuba. La nueva variedad en condiciones de investigación produce rendimiento agrícola medio de 8.4 y 5.5 t/ha en frío y primavera respectivamente, en condiciones de producción tuvo rendimiento de 8.9 t/ha; además el ciclo de germinación a cosecha está en el rango de 112- 137 días, posee granos cristalinos, los que se parten poco en el molino, produce el 59.97 % de granos enteros, es resistente a Tagosodes orizicolus y presenta resistencia intermedia a la Pyricularia grisea; esta variedad contribuirá al incremento de la producción en este cereal; por su resistencia a las plagas, permite disminuir el uso de plaguicidas y por ende existirá una menor contaminación ambiental, además ayudará a fortalecer la estructura varietal en el cultivo del arroz.

El trabajo fue realizado en un campo de producción comercial de arroz de la Empresa Agroindustrial de Granos “Sur del jíbaro”, Sancti Spíritus, Cuba, con la finalidad de evaluar la efectividad biológica de la tecnología que combina la aplicación de Oxadiargyl sobre lámina de agua con aniego después de fangueo del suelo y aspersión de Oxadiazón en estado de germinación del arroz. Se determinó que el tratamiento compuesto por la aplicación del herbicida Oxadiargyl (400 g ia/ℓ) a dosis de 600 g ia/ha, aniego durante 15 días, siembra con semilla sin tratar y aplicación del herbicida Oxadiazón (380 g ia/ℓ) a dosis de 684 g ia/ha en estado de germinación del arroz, fue el que mejor comportamiento tuvo en cuanto a rendimiento agrícola y control de arroz rojo (92.5 %), gramíneas (100 %), hojas anchas (95 %) y ciperáceas (100 %). El herbicida Oxadiargyl a dosis de 400 y 600 g ia/ha ocasionó afectación en la germinación y daño fitotóxico en los estados iniciales de crecimiento del arroz, pero éste se recuperó en el transcurso del ciclo del cultivo sin efecto negativo sobre el rendimiento agrícola.

Taking into consideration the observation of one green yellowsh clorosis in the plantations of rice, after the cold campaings and the disminishing of the agricultural efficiency of the cerial in areas of Saint Elena Land belonging to the fortified cooperatove of credits and service (FCCS) Camilo Cienfuegos in Las Nuevas, La Sierpe, Province of Sancti – Spiritus, were done foliars aplications with mineral fertilizing as, N.P.K to different doses and moments of applications, in order to obtain alternative of nutrition for the cultivation, the work was done on a green yellowish ferralitic ground since 2009 to 2011, using LP-5 cultivation doing the sowing by the method of transplantation, fertilization. It was done mixing 49L. ha-¹ of liquid warm humus with 0.35 Kg. ha-¹ of nitrogen, phosphorus and potassium. The results shown that the use of the foliar fertilization with liquid worm humus mixed with the N.P.K minerals, increased the efficiency, obtaining 5.3t. ha-¹ as an average in different variants used. The economic analysis showed that the treatment with 40% of nitrogen was reduced with seven foliars applications, it was highest to the witness N.P.K in 1.5t . ha-¹ of the grain obtaining a relative benefit of 4264.55 pesos by hectarea.

Taking in consideration the low fertility and degradation of rice soils, among other problems that contribute to rice yield decrease, the Grain Experimental Station and the Agricultural, Cattle and Industrial Complex carried out experiments and yield validations, respectively, in order to determine the influence of Fitomas – E (growth regulator), combined with organic and mineral fertilizer on rice production in vertisol. 11 treatimemts were employed in the experiments, including the controls, with four replications. Yied validations in production areas, just to know the response to Fitomas – E combined with Nitogen, Phosphorum and Potassium (NPK), compared to the control. Rice varieties J – 104 and Lp – 5 were utilized in the experiments and validations, respectively, with seed doses of 120 Kg. ha-1. More significant results were obtained when Fitomas – E was combined with foliar sprays of earthworm humus plus 50 and 100 % NPK, which showed statistical difference whith the remainder treatements; outstanding combinations were: Fitomas – E (2.0 t. ha-1) plus 50 and 100 “ NPK and earthworm humus (72.0 t. ha-1) in wuhich were obtained rice yield in the order of 5.57, 5.45, 6.05 and 5.87 t.ha-1 respectively. Economic analysis showed a profit of 6 981.09 Cuban pesos per hectare compared to the control when Fitomas – E plus 50 % NPK was applied. Field validation corroborated experimental results, obtaining 18.04 % rice yield increase when Fitomas – E was employed.

This research paper was carried out in the Physics- Chemistry and Industrial Testing Trials Laboratory, which belongs to The Post-Harvest Technology Department in The Grain Research Institute from Havana, Cuba. The industrial yield and cooking quality were evaluated in ten red rice lines, and two witnesses: commercial types of white rice IACuba- 31 and Jucarito-104. Samples were obtained from yielding local studies in the Grains Territorial Research Station at Sur de Jíbaro, province of Sancti Spíritus. It was found that in the industrial quality of different types of red rice, compared to the brown rice, the percent of the whole and broken grains regarding the red ones, was very high, and to the commercial white ones: Oryza sativa L . The 50% of the already studied lines of red rice were showing a good cooking quality. A great part of them used to show crystalinity values over 80% and good uniformity in the grain outer fisic appearance. Best integral results were obtained on lines: 18, 26 and 28.

Food production must be carried out using and maximizing the knowledge and the available technologies, however, one of the main limiting factors of agricultural production and crop quality are the pests and the diseases that attack the cultures from which plants start to grow until their harvest, and even in storage. The periodic sampling in the field generate information regarding the presence of pests, their population density, culture conditions, climatic variables and the presence and activity of natural enemies. Sampling methods vary according to the crop and phenological stage, as well as pests to be sampled. Within the basic components of Integrated Pest Management (IPM) is sampling or monitoring of pests, whose main objective is: "To determine when and what action should be made". The determination of the population of pests is a need for phytosanitary control program of any crop. Mechanical Compliance of phytosanitary measures at specified periods according to the needs always leads to wasteful spending, in work, instruments and environmental pollution.

The work was carried out during the years 2004 - 2011 in the international Center of Tsukuba, belonging to the International Agency of Cooperation of Japan and in the Territorial Station of Investigations of Grains "Sur del Jíbaro" in Sancti Spíritus with the objective value the employment of the nitrogenous fertilizer of Slow Liberation Ureaformaldehído on the index of agronomic efficiency in the use of the nitrogen and the increment of the agricultural yield for the production of rice; in the first one you study the speed of liberation of the nitrogen of the Ureaformaldehído and the conventional Urea to three temperatures (10; 17.5 and 25 ºC); in the second one studies effect of the fertilizer Ureaformaldehído on the agricultural yield and the index of agronomic efficiency in the use of the nitrogen, in the cultivation of the flooded rice. The main results showed the Ureaformaldehído reacted in a significant way in the measure the temperature was incremented, ending up being mineralized a percentage from 82 to the 100 days; on the other hand, the best yield was reached statistically, with the dose of 120 kg of N/ha, for the fertilizer Ureaformaldehído.

Trials were made in The Research Local Station of Grains areas, Sur del Jíbaro from 2005 through 2011. 27 morpho-agronomic characters were evaluated regarding the main red rice biotypes of straw-colored glumes in the province of Sancti Spíritus, Cuba, and in three commercial varieties of witness rice (IACuba-31, Perla de Cuba y Jucarito-104). It also was determined a broad diversity and variations in these features that permitted to differenciate the biotypes between them and with other rice cultivars. The purple pigmentation in some parts of the plants in the great majority of such biotype is an observable feature, seen easily, that make contrasts with the already researched, by which it helps a lot in identifying them. The great majority of the biotypes of straw-colored glumes featured an over-growned size in their sprouts, lengths and longer flag leaves, with also a prone feature to loose its grain, its nighty, broad seed and a particular resistance to Pyricularia grisea; but shorter and lighter but it also yields less per hectares. it has shown resistant to Tagosodes orizicolus, respecting the witness cultivars.

A lowland rice trial was carried out in a montmorillonitic clayed Vertisol (Gley Vetico) during 2011-2012 Dry season and 2012 Wet Season, in order to select and introduce rice cultivars with a high efficiency on nitrogen utilization from mineral fertilizers in grain production. Four rice cultivars were tested: IACuba-31; IACuba-30; IACuba-36 and LP-5 (as a control); three nitrogen levels were applied to each of them: 0; 150 and 180 kilograms per hectare (kg. ha-1). Main results obtained agree with previously ones when level of 150 kg. N. ha-1 showed a superior response in nitrogen utilization efficiency, highly significative to dose of 180 kg. N. ha-1; in the same way, best results were shown by IACuba-31 and IACuba-36 rice varieties, with agronomic efficiencies of 42.16 and 40.06 kg of rice per kg of nitrogen applied; in the same way those varieties obtained agronomic efficiencies, highly significative in the Wet Season, with 36.21 and 35.76 kg of rice per ha of nitrogen applied, respectively, all of which contributes to the knowledge that efficient use of nitrogen is a factor of high productivity when rice varieties are recommended.

A trial was done in rice areas infested with red rice in “Sur del Jíbaro” Rice Complex, Sancti Spiritus, Cuba, during 2011 wet season, where LP- 5 rice variety was sown. Effectiveness of 10 farmers in red rice identification while working on negative selection in the rice fields was evaluated in three growing stages of the plant: 15- 40 days old, 50- 70 days old, both after germination and the last in paniculation – grain filling stage. Best efficiency in identification and extraction of red rice plants from the field was obtained during paniculation- grain filling stages, because that ’s the moment when the greatest difference between red rice and the cultivated one is shown, although more injury is done to the rice plant. It is necessary to realize three or more negative selections in different growing stages of the rice plant; in order to get a good success in controlling this weed, the best moments are: early in the life cycle of the rice plant and another during paniculation- grain filling of the rice plant.

Field trials were carried out in The Regional Research Grain Station “Sur del Jíbaro”, Sancti Spíritus, in order to study the infestation effect of 0, 12, 25, 50, 100 and 200 red rice plants per square meter (m2) on growth and yields of commercial variety J-104, seeded at 50, 100, 200 and 300 plants/m². Yield of J-104 rice variety decreased with the increase in red rice density. Crop yield decrease in the dry season ranged from 10.7 to 94.8% with infestations of 12 and 200 red rice plants /m², respectively; while in the wet season changed from 11.4 to 91.5 % with similar level in infestations. In both seasons 12 red rice plants were enough to cause a significant reduction in commercial rice yields in relation to the control treatment (without red rice infestation). The lost in crop yield was due to the decreased in panicles/ m² and filled grains per panicle, caused by the interference with red rice.

A searching was carried out in rice areas of the Agricultural and Industrial Complex “Sur del Jíbaro” and the Cooperative- countryman Sector in Sancti Spíritus, in order to collect different types of red rice. A total of 129 samples were taken and out of these selected the non susceptible lines to threshing with red pericarp and without awns, with the objective of their morphological characterization and to evaluate its productive potential in comparison to rice varieties Perla, IACuba 31 and J- 104. 17 lines were chosen, 65 % of them showed green color in leaves, translucent ligula and auricle and dewlap of greenish- yellow color, similar to the commercial rice varieties. 17.6 % presented semidwarf plants, 58.8 % intermediate height and the remainder were tall plants. All the lines showed vigorous plants. 6 % of the lines in the wet season and between 56 and 68 % in the dry season also showed agricultural yields superior to the control variety of a better behavior. The rice lines with red pericarp presented seeds of similar width and thickness as those of commercial varieties of white rice, although with a minor length.

In order to know the reason on the low utilization of the rice seed sown in paddy areas, during 2008 and 2009 years, a research was carried out composed of three experiments: 1. Loss diagnosis and managements realized on seed of varieties LP-5 and J-104. 2. Petri dishes assay in order to know seed quality 3. Plot experiments on rice plant nutrition in order to obtain a better grain filling Results showed the bad quality of employed seeds: 53 and 59% of both rice varieties (LP-5 and J-104, respectively) presented a poor formation with insufficient grain filling, from which it is impossible to arise normal rice seedlings, as was seen in the observations done, and besides the high number of dead embryos obtained: 13.3 % for variety LP-5 and 33.3% for J-104. Nutrition plots reflected importance on the utilization of fertilizers in adequate moments of life cycle of the rice plant, especially nitrogen, that must be in the early stages of growth and lastly in the reproductive phase; treatment 4, which responded to this management was superior, yielded 11.52 tones of paddy per hectare in 2008-2009 Dry Season and 7.83 in 2009 Wet Season, with statistical difference to all other treatments.

An experiment was carried out in Estación Experimental de Granos “Sur del Jíbaro”, Sancti Spiritus, during 2006-2007 dry season in a Vertisol soil and had as an objective to evaluate the effect of split doses of nitrogen over the increment of rice yield in a wetland rice ecosystem, A factorial analysis made to agricultural yield values showed that exist a highly significant interaction between the used of nitrogen fertilization scheme and the nitrogen levels studied; in the same way was showed that nitrogen fertilization scheme and nitrogen levels have a highly significant effect over the agricultural yield, so, changing the fertilizer doses or the fractionation of it or both modified the plant behavior and the grain yield. It was observed also that the combination which showed more grain yield was the corresponding to V scheme with 140 kg de N. ha-1 in which it was significantly favored the grain production, recognizing that when it is adopted a good practice of nitrogen fertilization management it is obtained a high productivity with a high recuperation of the applied nitrogen.

Seed treatment has become of a great importance on principal crops, especially on intensive cropping, where sanitary protection is necessary from the days just after germination up to advanced growth stages of the crop. This experiment was carried out at the Entomology Laboratory of “Sur del Jibaro” Rice Experimental Station, Sancti Spiritus, Cuba, from July 28, 2009. Seed treatment with formulation of Thiamethoxam (262.5 g a.i./l) + Difeconazol (25 g a.i./l) + Fludioxonil (25 g a.i./l), equal to 312.5 g a.i./l FS as a total, was applied to one kilogram of rice seed, variety J-104, utilizing the two proposed doses to evaluate (60 and 100g a.i./100 kg of seed). 100 rice seeds were placed in Petri dishes. Four days after this, germination percentage was evaluated. A control (without chemical treatment) and four replications were utilized. Same day of pesticide application, germination percentage was between 87.6 and 89.6. Fifty days after seed treatment with 100 g a.i./100 kg of seed, germination percentage was 74.3, even by that time, remainder treatments were over 80%. Up to this time seed is not allowed to be used according to Cuban Technical Instructions for rice culture.

During 2005 till 2006 and 2006 till 2007.dry seasons and 2007 Wet Seasons, a plot experiment was carried out at the Rice Experimental Station “ Sur del Jíbaro”, in Sancti- Spíritus, in order to know the response of four short duration rice varieties (LP-5, IACuba 31, Reforma) and two genetic lines (4561 and 4697) to Spotted Grain Diseases and yield of rice in these conditions. The experiment was directed dry seeded at a distance of 15 centimeters between rows. A complete block design was used, composed of six treatments and four replications in a Vertisol, typical of cuban rice soils. Highest yields were obtained by Reforma and IACuba 31 varieties in both seasons: 5.23 and 5.00 t/ha in Dry Seasons and 4.50 each variety in Wet Seasons, respectively. All the varieties and lines testd showed their resistance, not only to Spotted Grain Diseases, but also to Pyricularia grisea, Cercospora oryzae. Highest income was obtained by the variety Reforma (2 512 USD/ha and 2 160 USD/ha), during Dry and Wet Seasons, respectively. By the other side, line 4 697 obtained the lowest incame (1 584 and 1 472 USD/ha) in Dry and Wet Seasons, respectively.

A total of 129 samples of weedy rice plants (Oryza sativa L.) were collected in different rice areas in “Sur del Jíbaro” Rice Enterprise and also in others belonging to small farmers, in order to observe later on their morphological characteristics and growth performance in plots of the Rice Experimental Station, in Sancti Spiritus, too. Results showed that the largest part of weedy rice population awned wider and thicker grains than Perla and J-104 commercial rice varieties; on the other hand, the grains were not so long and so heavy as those of mentioned varieties. From 64.0 up to 70.1 % of weedy rice population showed awn seeds of 0.1 to 9.5 cm. long and a red coloration in 35.0 to 36.8 % of them. Those grains presented red keen points in 53 % of the rice population and also a brown mottled and black coloration in glumes of 33 and 26 %, respectively; all the characteristics stated before made a clear differentiation between weedy and commercial rice in the field and also in the laboratory. Red coloration predominated in the pericarp of the largest part of weedy rice population (81.5 % in Wet Season and 87.6 % in Dry Season).

Tibraca limbativentris was first reported in Cuba in 2007 by Dr. Horacio Grillo, among some insects collected from experimental plats at the Rice Research Institute in Bauta, Havana and also from “Sur del Jíbaro” Rice Experimental Station in Sancti Spíritus. This experiment was carried out at “Sur del Jíbaro” Station in order to determine the control done by Thiamethoxam over T. limbativentris adults. Three formulations of Thiamethoxam + Difenoconazol + Fludioxonil (312.5 g ai./l FS) for seed treatment were evaluated; and Thiamethoxam + Lambda+cyhalotrina (247 g ai/l) and Thiamethoxam (250 g ai/l), both for foliar treatment. All the Thiamethoxam foliar treatments obtained a control of more than 70% six days after their application.Best result was obtained by Thiamethoxam + Lambda-cyhalotrina (247 g ai/l) per hectare. By the other hand, seed control resulted low, among other problems, because of arrangement moment of T. limbativentris adults. Feeding and egg deposition of T. limbativentris in treatment without insecticide application resulted the highest of all, obtaining 41.6% of dead hearts, six days after insects arrangement.

El trabajo se realizó en la Estación Territorial de Investigaciones del Arroz “Sur del Jíbaro”, durante la campaña húmeda 2007, en un suelo Gley Vértico Típico y tuvo como objetivo evaluar la eficacia de los aportes de nitrógeno de la Sesbania rostrata, en la substitución de la fertilización mineral nitrogenada. Se estudió la incorporación de la Sesbania r. con dosis de nitrógeno de 0; 70; 140 y 210 kg de N. ha-1 . Los principales resultados mostraron que la incorporación de Sesbania rostrata posibilitó reducir en un 50 % la dosis de nitrógeno recomendada para esta condición de suelo – variedad, así también, se determinó que la dosis de nitrógeno mineral adecuada en suelos Gley Vértico Típicos, al incorporar Sesbania r. , es de 70 Kg de N. ha-1.

El trabajo fue realizado en el 2007, en el Centro Internacional de Tsukuba, perteneciente a la prefectura de Ibaraki, Japón con el objetivo de determinar la influencia que tienen el momento de aplicación fraccionada y la dosis de nitrógeno (N) sobre el Rendimiento, además de la incidencia y severidad de la enfermedad Rhizoctonia solani en la variedad de arroz japónica Akitakomachi. La aplicación de fósforo y potasio se realizaron de base antes del trasplante y las de nitrógeno fueron en tres momentos: a la hora del trasplante, en el máximo macollamiento y en la iniciación de la panícula, según el tratamiento a estudiar. Se realizaron evaluaciones de desarrollo y crecimiento de la planta de arroz, así como el rendimiento y sus componentes. En los parámetros de crecimiento evaluados, los mayores valores fueron del tratamiento 4 (75-0-45 kg de N/ha), seguido por los tratamientos 2 (50-30-0), 3 (50-0-30) y 1 (0-0-0). El tratamiento con mayor incidencia y severidad de R. solani fue el 4 (75-0-45) con 5.80 y 0.18 %, respectivamente, siendo similares el 1(0-0-0) y 2(50-30-0), con menor porcentaje en ambos parámetros fue el tratamiento 3(50-0-30) con 3.7 y 0.13, respectivamente. En cuanto al rendimiento agricola, el mayor valor lo obtuvo el tratamiento 4 (75-0-45), seguido por el 2 (50-30-0), 3 (50-0-30) y 1 (0-0-0) con 7.88, 7.39, 6.73 y 2.63 t/ha, respectivamente.

Según diagnóstico efectuado en áreas del Complejo Agropecuario e Industrial (CAI) “Sur del Jíbaro”, la Estación Experimental del Arroz se realizó validaciones en la Unidad Básica de Producción Cooperativa (UBPC) Las Nuevas, pertenecientes al citado complejo en La Sierpe, Sancti Spíritus, para conocer el efecto del Estiércol Vacuno como alternativa de nutrición en el incremento del rendimiento en arroz y fertilidad de sus suelos.El trabajo se ejecutó en el campo #26 de la mencionada UBPC durante tres campañas de siembra sucesivas, a partir de Primavera 2005, en un suelo Gley Vértico Típico; en la primera siembra (Primavera 2005) se aplicó estiércol vacuno en 2.01 ha, a 37 t.ha-1. El abono se esparció en la superficie, incorporándose al suelo y la siembra se efectuó 29 días posteriores a su aplicación, comparándolo con el resto del campo como testigo, donde se aplicó solamente N, P, K, según Instructivo Técnico. Se sembró a voleo, con semilla pregerminada de la variedad J-104; y la preparación del suelo fue por fangueo directo. En Frío 2005 – 2006 y Primavera 2006, se sembró nuevamente dicho campo, sin aplicar materia orgánica, para observar su comportamiento. Los resultados mostraron que donde se había aplicado estiércol vacuno, todas las campañas superaron al testigo (sin materia orgánica), mostrando diferencia significativa en todos los casos, con valores de 0.94, 1.52 y 1.65 toneladas de arroz cáscara por hectárea, en las campañas de Primavera 2005, Frío 2005 – 2006 y Primavera 2006, respectivamente, representando un incremento promedio del 35 % en los rendimientos del arroz para las tres campañas estudiadas.

El trabajo se realizó en la Estación Territorial de Investigaciones del Arroz (ETIA) “Sur del Jíbaro” y en el Complejo Agropecuario e Industrial (CAI) “Sur del Jíbaro”, durante los años 2006 y 2007, con el objetivo de evaluar la eficacia de la incorporación de la urea como fuente nitrogenada. El mismo constó de dos ensayos: Efecto de la incorporación de la urea hasta la profundidad de 20 cm. y su proporción con relación a la fertilización nitrogenada adicional en el momento de iniciación de la panícula, sobre el contenido relativo de nitrógeno y el rendimiento agrícola, realizado en la ETIA y Ensayo de validación en condiciones de producción de la incorporación de la urea, ejecutado en áreas del CAI arrocero. Los principales resultados mostraron que cuando se incorporó el 70 % del nitrógeno antes de la siembra y el restante 30 % del elemento, se suministró al momento de la iniciación de la panícula se obtuvo el mejor resultado en las condiciones de la ETIA; mientras que en condiciones de producción los resultados mostraron que en la variante donde se incorporó el nitrógeno la emisión de tallos improductivos se vio reducida significativamente, mientras el número de espiguillas por panículas y el llenado de las mismas se incrementó significativamente; de un modo semejante el rendimiento agrícola se mostró significativamente superior al testigo fraccionado, con un incremento de 0.48 t . ha-1 de arroz cáscara; todo lo cual sugiere que la disponibilidad de nitrógeno desde la etapa de plántula, conduce a la formación de tallos gruesos, vigorosos y uniformes, capaces de formar panículas sin anomalías y propiciar un incremento de la productividad.

En la Estación Territorial de Investigaciones del Arroz “Sur del Jíbaro” fue estudiada durante las campañas seca 2005- 2006 y húmeda 2006 una población de arroz rojo procedente de colectas realizadas en campos de producción y semilla del CAI “Sur del Jíbaro” y áreas de campesinos de la provincia de Sancti Spíritus. Se determinó que el color púrpura es un carácter distintivo de la población de arroz rojo al manifestarse en el 50 % de las vainas, 21 % de los limbos de las hojas, 9.4 % de las lígulas, 43 % de las aurículas y 43.5 % de la inserción de la vaina con el limbo. Se encontró que entre un 4.6 y un 17. 2 % de los tipos de arroz rojo presentan una longitud de las plantas similar o inferior a la variedad J- 104 y entre un 0.9 y 9.7 % similar o inferior a la Perla. La población de arroz rojo presentó un elevado potencial productivo expresado en panículas largas con gran cantidad de llenos y bajos porcentajes de vaneo. El color rojo de las aristas permite distinguir el arroz rojo del comercial en el proceso de selección negativa. Entre un 0 y 13.8 % de los tipos de arroz rojo comenzaron a panicular antes que la variedad de ciclo corto Perla y completaron su ciclo primero que ésta el 2.2 a 17.8 %, mientras que del 16.9 al 79.1 % del arroz rojo inicio la paniculación antes que la variedad de ciclo medio J- 104 y completaron su ciclo primero que ésta el 62 al 70.8 %. Ninguna de las características morfológicas se expresó en la totalidad de la población de arroz rojo por lo que se necesitan varias de ellas para diferenciarlos con seguridad de las variedades comerciales Perla y J- 104.

Spodoptera frugiperda está reportado como una plaga importante en la mayoría de países de Latinoamérica. Para determinar la efectividad de las estrategias de control se infestaron plántulas de tres variedades de arroz (Fedearroz 50, Tailandia3 y Tailandia 4) A los 15 y 25 días después de siembra inocularon con larvas de S. frugiperda de tercer instar (0, 100 y 400 larvas/m2), luego se cubrió las plántulas usando jaulas de nylon. No se encontraron diferencias significativas en rendimiento en ninguno de los tratamientos, lo cual correspondió con el área foliar recuperada por las plantas. Si esta plaga se controla en el cuarto instar, parece ser que se presenta poco daño económico al cultivo.

En el Centro internacional Tsukuba, Japón fueron realizados ensayos en condiciones de macetas con el propósito de evaluar el efecto que producen diferentes niveles y manejos de agua sobre la emergencia y crecimiento de Echinochloa crus-galli P. Beauv. var. crus-galli. Se determinó que el aumento de la lámina de agua ejerció dos efectos sobre E. crus-galli, el retraso en el crecimiento que se manifestó de forma significativa a partir de una lámina de 5 cm y el de disminución de la cantidad de plántulas que sobresale la lámina de agua observado a partir de 10 cm. y que tomó un valor máximo con 20 cm. El establecimiento de una profundidad de agua inicial de 5 cm y posterior aumento a 10 y 15 cm cuando las plántulas de E. crus-galli alcanzaron 1-2 hojas y 2,5 cm de longitud provocaron un efecto similar sobre la emergencia y crecimiento de esta maleza que sus respectivos testigos con láminas permanentes de 10 y 15 cm. durante todo el ensayo.

El trabajo se realizó en los campos experimentales de la Estación del Arroz “Sur del Jíbaro” y en áreas de producción del Arroz Popular de los municipios La Sierpe, Fomento y Taguasco, provincia de Sancti Spiritus. Se estudiaron cinco variantes para la realización del trasplante manual en hileras, las cuales fueron comparadas con el trasplante tradicional al Azar y entre ellas mismas; se evaluó la productividad (ha/hombre/jornada) y el rendimiento agrícola (t/ha). Los resultados mostraron que la variante de mayor productividad fue el Trasplante Tradicional al Azar con 0.086 ha/hombre/jornada, en el resto de los tratamientos ésta se redujo hasta valores de 0.036, cuando se utilizó el marcador de dos sogas; por otra parte el rendimiento agrícola de todos los tratamientos donde se realizó el trasplante en hileras supero significativamente al trasplante tradicional al Azar, el mejor resultado fue alcanzado por el Marcador Triangular 20x20cm y 1.5 m de ancho.