ABSTRACT With the aim of evaluating the agronomic characteristics of three lettuce cultivars under different types of soil cover in the winter - spring period, an experiment was conducted between the months of July and October 2019 in the district of Coronel Oviedo, Paraguay. The experimental design used was complete randomized blocks with a 3 x 4 factorial arrangement, totaling twelve treatments with four replications. Three lettuce cultivars (Tainá, Julia and Legacy) and four types of soil cover (black plastic, bicolor white/black plastic, bicolor silver/black plastic, and control without soil cover) represented the factors under study. Were evaluated total and commercial number of leaves, total and commercial fresh mass, height, and diameter of the head per plant. The results obtained indicate that there were no significant differences between the cultivars in the evaluated characteristics, except for plant diameter, where Julia (30.09 cm) was superior to Legacy. It was observed that ground covers showed statistical superiority in all variables evaluated, in relation to the control, except for head height. The interaction between cultivars and soil cover was not significant. The silver/black, white/black, and black plastic covers promote greater commercial fresh mass per plant (241.11 g, 204.03 g, 218.05g), commercial number of leaves (21.20; 20.30; 20.40) and head diameter (11.54 cm, 11.10 cm, 11.20 cm). It is concluded that soil cover improves the agronomic characteristics of the lettuce cultivars evaluated.

RESUMEN Con el objetivo de evaluar las características agronómicas de tres cultivares de lechuga arrepollada sobre diferentes tipos de cobertura de suelo en el periodo invierno - primavera, fue conducido un experimento entre los meses de julio a octubre de 2019 en el distrito de Coronel Oviedo, Paraguay. El diseño experimental utilizado fue de bloques completos al azar con arreglo factorial 3 x 4, totalizando 12 tratamientos con cuatro repeticiones. Los factores en estudio estuvieron representados por tres cultivares de lechuga arrepollada (Tainá, Julia y Legacy) y cuatro tipos de cobertura de suelo (plástico negro, plástico bicolor blanco/negro, plástico bicolor plateado/negro y testigo sin cobertura de suelo). Fueron evaluados: número total y comercial de hojas, diámetro de planta, masa fresca total y comercial, altura y diámetro de cabeza por planta. Los resultados obtenidos indican que no hubo diferencias significativas entre cultivares en las características evaluadas, a excepción del diámetro de planta, donde Julia (30,09 cm) fue superior a Legacy. Se observó que las coberturas de suelo presentaron superioridad estadística en todas las variables evaluadas, con respecto al testigo, a excepción de altura de cabeza. La interacción cultivares con cobertura de suelo no fue significativa. Las coberturas de plástico de color plateado/negro, blanco/negro y negro, promueven mayor masa fresca comercial por planta (241,11 g, 204,03 g, 218,05 g), número comercial de hojas (21,20; 20,30; 20,40) y diámetro de cabeza (11,54 cm, 11,10 cm, 11,20 cm). Se concluye que la cobertura de suelo mejora las características agronómicas de los cultivares de lechuga evaluados.

ABSTRACT Herbigation has several advantages, such as the reduction of drift, the operator's exposure to the product, and the reduction of costs associated with weed management. This work was carried out in the Department of Caaguazú, Paraguay, during the period from March to October 2018, to evaluate the efficacy of different doses of pre-emergent herbicides applied via irrigation water in the transplanted onion crop. The experimental design used was the randomized complete blocks with arrangement in divided plots (5>5), where the main plot consisted of the herbicides (Flumioxazin, Oxyfluorfen, Pendimethalin, Trifluralin and S-metolachlor) and the subplots of the doses of Flumioxazin (0, 15, 25, 35 and 45 g a.i. ha-1), Oxyfluorfen (0, 240, 312, 384 and 456 g a.i. ha-1); Pendimethalin (0, 800, 1,000, 1,200 and 1,400 g a.i. ha-1); Trifluralin (0, 576, 768, 960 and 1,152 g a.i. ha-1) and S-metolachlor (0, 480, 960, 1,440 and 1,920 g a.i.ha-1) with four repetitions. The weeds with the highest relative importance were: Digitaria horizontalis, Richardia brasiliensis, Galinsoga parviflora, Bidens pilosa, Amaranthus spinosus and Portulaca oleracea. Herbicides in the studied doses applied through irrigation water were effective on sensitive species and did not cause symptoms of phytotoxicity on onion crops until 21 DAA. The evaluated doses of Oxyfluorfen, Pendimethalin, Trifluralin and S-metolachlor did not affect the bulb yield in the transplanted onion crop.

RESUMEN La herbigación tiene como ventajas la reducción de la deriva, menor exposición del operador al producto y la disminución de los costos asociados al manejo de arvenses. Este trabajo se realizó en el Departamento Caaguazú, Paraguay, entre marzo y octubre de 2018, con el objetivo de evaluar la eficacia de diferentes dosis de herbicidas preemergentes, aplicados mediante riego por goteo, en el cultivo de cebolla trasplantada. Se empleó un diseño experimental de bloques completos al azar con arreglo en parcelas divididas (5>5), donde la parcela principal estuvo constituida por los herbicidas y las subparcelas por las dosis: Flumioxazin (0, 15, 25, 35 y 45 g i.a. ha-1), Oxyfluorfen (0, 240, 312, 384 y 456 g i.a. ha-1), Pendimethalin (0, 800, 1.000, 1.200 y 1.400 g i.a. ha-1), Trifluralin (0, 576, 768, 960 y 1.152 g i.a. ha-1) y S-metolachlor (0, 480, 960, 1.440 y 1.920 g i.a. ha-1), con cuatro repeticiones. Las arvenses con mayor importancia relativa fueron: Digitaria horizontalis, Richardia brasiliensis, Galinsoga parviflora, Bidens pilosa, Amaranthus spinosus y Portulaca oleracea. Los herbicidas utilizados fueron eficaces sobre las especies sensibles y no causaron síntomas de fitotoxicidad sobre el cultivo de cebolla hasta los 21 días después de la aplicación. Las dosis empleadas de oxyfluorfen, pendimethalin, trifluralin y s-metolachlor no afectaron el rendimiento de bulbos del cultivo de cebolla trasplantada.

RESUMO O rendimento da planta de morango melhora si acumularem uma certa quantidade de horas frias, o que não ocorre naturalmente em condições de clima tropical e subtropical. Este estudo avaliou características agronómicas de 14 genotipos de morango sometidos a vernalização das mudas, produzidas em vasos, antes do transplante a campo. As mudas foram armazenadas em câmara fria a 5 °C por um período de 576 horas. Os genotipos avaliados foram Camino Real, Festival, Florida Eliane, Sweet Charliefp, Sweet Charlie, Dover, IAC Guaraní, Corea, Early Bright, e clones híbridos Dover × Rosalinda1 Dover × Rosalinda4, Dover × Oso Grande, Dover × Esplendida e Dover × Aichi. Os 14 genotipos do grupo controle não receberam tratamento de frio. Cada unidade experimental foi composta por 15 plantas. O delineamento utilizado foi o de blocos casualizados, em esquema fatorial 14 × 2, com três repetições. Não houve interação significativa entre os fatores para as características avaliadas, mas houve efeito significativo da vernalização das mudas sobre número total de frutos por planta, produção total e comercial de frutos por planta. ‘Dover x Oso Grande’, ‘Florida Eliane’, ‘Camino Real’ e ‘Festival’ produziram a maior quantidade de frutos grandes por planta. Vernalizando as mudas de morango aumentaram o número de frutos médios e pequenos por planta. Pelos resultados obtidos pode se concluir que a vernalização é uma técnica que poderia ser utilizada em condições de clima tropical para melhorar o cultivo e aumentar a produtividade do cultivo de morango.

ABSTRACT Strawberry plant yields improve if they accumulate a certain number of cold hours, which does not occur naturally under tropical and subtropical climatic conditions. This study evaluated the agronomic characteristics of potted transplants from 14 strawberry genotypes that had been subjected to vernalization treatment prior to planting in the field. The transplants were stored in a cold chamber at 5°C for 576 h. The genotypes used in the experiment were Camino Real, Festival, Florida Eliane, Sweet Charliefp, Sweet Charlie, Dover, IAC Guaraní, Corea, Early Bright, and hybrid clones Dover × Rosalinda1 Dover × Rosalinda4, Dover × Oso Grande, Dover × Esplendida, and Dover × Aichi. The 14 genotypes in the control group received no vernalization treatment. Each experimental unit consisted of 15 plants. A randomized complete blocks experimental design was used with a 14 × 2 factorial arrangement and three repetitions. Subjecting the strawberry transplants to the vernalization treatment had a significant effect on the total number of fruits per plant and total and commercial yield of fruits per plant, but there was no significant interaction between the factors and the evaluated yield and growth characteristics. Dover × Oso Grande, Florida Eliane, Camino Real, and Festival produced the greatest numbers of large fruits per plant. Vernalizing strawberry transplants increased the yield and the number of medium and small sized fruits per plant. The results showed that vernalization is a technique that could be used in tropical climate conditions to improve strawberry cultivation productivity.

ABSTRACT: This work evaluated the potential production and quality of daughter plants of 20 strawberry genotypes produced in containers in a protected environment. The experimental design used was randomized complete blocks with three repetitions. It was evaluated: number of daughter plants produced per mother plant, number of leaves, leaf area, root length, crown diameter, fresh, and dry mass of the aerial part and the root system. Data were subjected to analysis of variance, and means were compared by Tukey test at a 5% probability. Cultivars responded differently in the production of daughter plants, number of leaves, fresh and dry mass of the aerial part and the root system. The results showed that the Dover x Esplendida genotype presented the largest number of daughter plants, while Sabrina had the highest fresh and dry mass of the aerial part and fresh mass of the root system. Sweet Charlie FP and Sabrina stood out for the high dry matter content of the root system. There were no differences in the variables leaf area, root length, and crown diameter. The daughter plants produced by the evaluated genotypes presented the minimum requirements in terms of the number of leaves and crown diameter.

RESUMEN: Este trabajo fue realizado con el objetivo de evaluar el potencial de producción y calidad de plantas hijas de 20 genotipos de frutilla producidas en contenedores en ambiente protegido. El diseño experimental utilizado fue de bloques completos al azar con tres repeticiones. Se evaluaron: número de plantas hijas producidas por planta madre, número de hojas, área foliar, longitud de raíz, diámetro de corona, masa fresca y seca de la parte aérea y del sistema radicular. Los datos fueron sometidos al análisis de varianza y a la comparación de medias por la prueba de Tukey al 5% de probabilidad. Los cultivares respondieron en forma diferenciada en la producción de plantas hijas, número de hojas, masa fresca y seca de la parte aérea y del sistema radicular. Los resultados mostraron que el genotipo Dover x Esplendida presentó el mayor número de plantas hijas, mientras que Sabrina la mayor masa fresca y seca de la parte aérea y, masa fresca del sistema radicular. Sweet Charlie FP y Sabrina se destacaron por el elevado contenido en materia seca del sistema radicular. No se encontraron diferencias en las variables área foliar, longitud de raíz y diámetro de corona. Las plantas hijas producidas por los genotipos evaluados presentaron los requisitos mínimos exigidos en cuanto a número de hojas y diámetro de corona.

Resumen La producción de frutilla en Paraguay es realizada por pequeños productores, usando escasa tecnología y obtención de baja productividad, con la necesidad de ampliar los genotipos y la tecnología utilizada. El objetivo de esta investigación fue evaluar la calidad de frutos de genotipos de frutilla en función a la vernalización. El diseño utilizado fue el de bloques completos al azar con arreglo factorial 14x2. Los factores estuvieron constituidos por los genotipos y la vernalización con 15 plantas por tratamiento y tres repeticiones. Las mudas fueron mantenidas en cámara fría a 5°C, con 8 horas luz artificial y 16 de oscuridad por un periodo de 25 días. Se utilizaron cinco frutos por tratamiento y fueron evaluadas la cantidad de sólidos solubles totales, acidez titulable, relación de sólidos solubles totales con acidez titulable, relación longitud/diámetro, relación: diámetro del cáliz/diámetro del fruto, longitud del pedúnculo y pérdida de masa en postcosecha. Los datos obtenidos fueron sometidos a análisis de varianza en esquema factorial simple y las medias comparadas por el test de Tukey al 5% de probabilidad de error. La vernalización de las mudas no afectó la forma de los frutos de frutilla ni el contenido de sólidos solubles totales, pero aumentó el porcentaje de ácido cítrico. Así mismo, aumentaron la longitud del pedúnculo de la planta y la extensión del cáliz del fruto. Por otro lado, la vernalización disminuyó la pérdida postcosecha de masa fresca, pero no afectó la conservación de frutos a 5°C. Los genotipos Festival y Florida Eliane pueden ser recomendados para consumo in natura y los genotipos Dover y Oso Grande para industria.

Abstract Strawberry production in Paraguay is carried out by small producers, using minimal technology and obtaining low productivity, with the need to expand strawberry genotypes and production techniques. The aim of this study was to evaluate fruit quality of strawberry genotypes according to vernalization. A randomized block design with factorial arrangement 14x2 was performed; factors were genotypes and chilling using 15 plants per treatment and three replicates. Plants were kept in cold room at 5°C, with 8 hours of artificial light and 16 of darkness for a period of 25 days. Five fruits were used per treatment and were evaluated as follows: the amount of total soluble solids, titratable acidity and ratio of total soluble solids to titratable acidity, length/diameter ratio, calyx diameter/fruit diameter ratio, peduncle length and mass loss in postharvest. Data obtained were subjected to analysis of variance simple factorial scheme and averages compared by Tukey test at 5% probability. Vernalization of strawberry plants did not affect fruit shape or total soluble solids content, but increased the percentage of citric acid. Length of peduncle and calix extension had achieved an increasing due to vernalization and decreased postharvest loss of fresh mass, but did not affect fruit preservation at 5°C. Festival and Florida Eliane genotypes may be recommended for in natura consumption and Dover and Oso Grande genotypes for industry.

ABSTRACT Peanuts are an excellent agricultural alternative for farmers from Chaco Central because of its nutritional value and adaptability to semiarid climates. The research was conducted between January and June 2013, at the Chacra Experimental Isla Poí from the Servicio Agropecuario of the Cooperative Society Chortitzer Ltda., district of Loma Plata (22° 29' 38.7 '' South and 59° 43'53.2'' West), Department of Boquerón and on a farm producer from the district of Teniente Irala Fernández (22° 58' 20,9 '' South and 59° 31' 42,8 '' West), Department of Presidente Hayes, Paraguay, in order to evaluate the agronomic performance of five varieties of semi erect peanut. The experimental design was randomized complete blocks with factorial arrangement 2 x 5, with four replicates. The factors were constituted by the two localities (Isla Poí and Teniente Irala Fernández) and the five varieties (Pytá, Negrito, Moroti, Rosado and Tatú IAC), considering the variables yield with shell and without shell, percentage of shell and mass of thousand grains. The data obtained were subjected to analysis of variance and the means compared by Tukey test at 5% probability of error. There was no interaction between factors for any of the characteristics studied. Significance between locations for the variables evaluated was found, except for the percentage of shell. In Teniente Irala Fernandez grain yield and mass of a thousand grain was 25.74% and 31.11%, higher than in Isla Poí. Among varieties there were differences in the mass of one thousand grains where Pytá (503.62 g) was superior to Negrito (423.50 g). Grain yield ranged from 1.39 t ha-1(Negrito) and 1.79 t ha-1 (Pytá), indicating that the cultivation of peanuts is an agronomical alternative for the conditions of Paraguayan Central Chaco.

RESUMEN El maní es una excelente alternativa agrícola para los pequeños agricultores del Chaco Central, debido a su valor nutritivo y adaptación a climas semiáridos. El trabajo de investigación fue realizado entre enero y junio de 2013 en la Chacra Experimental Isla Poí del Servicio Agropecuario de la Sociedad Cooperativa Chortitzer Ltda., distrito de Loma Plata (22°29'38,7'' Sur y 59°43'53,2'' Oeste), Departamento de Boquerón y en una finca de productor del distrito Teniente Irala Fernández (22°58'20,9'' Sur y 59°31'42,8'' Oeste), Departamento de Presidente Hayes, Paraguay, con el objetivo de evaluar el desempeño agronómico de cinco variedades de maní de porte semi erecto. El diseño experimental fue de bloques completos al azar con arreglo factorial 2 x 5, con cuatro repeticiones. Los factores estuvieron constituidos por las dos localidades (Isla Poí y Teniente Irala Fernández) y las cinco variedades (Pytá, Negrito, Moroti, Rosado y Tatú IAC), considerando las variables rendimiento con cáscara y sin cáscara, porcentaje de cáscara y masa de mil granos. Los datos obtenidos fueron sometidos al análisis de varianza y las medias comparadas por el test de Tukey al 5% de probabilidad de error. No hubo interacción entre los factores para ninguna de las características estudiadas. Se encontró significancia entre localidades para las variables evaluadas, a excepción del porcentaje de cáscara. En Teniente Irala Fernández el rendimiento de granos y la masa de mil granos fue de 25,74% y 31,11%, superior al de Isla Poí. Entre variedades hubo diferencias solo en masa de mil granos, donde Pytá (503,62 g) fue superior a Negrito (423,50 g). El rendimiento de granos estuvo entre 1,39 t ha-1 (Negrito) y 1,79 t ha-1 (Pytá) indicando que el cultivo del maní es una alternativa agronómicamente viable para las condiciones del Chaco Central paraguayo.

The experiment was carried out in the greenhouse of seedling production of the Centro Hortícola of the Facultad de Ciencias Agrarias, Universidad Nacional de Asunción, Paraguay, from September to October, 2011. The influence of the floating system and types of substrates on the growth of tomato seedlings (Lycopersicon esculentum Mill) was determined. The treatments were a combination of two seedlings production’s systems (floating and conventional) and two types of substrates (commercial and vermin-compost). Randomized complete blocks with a factorial arrange 2 x 2 was used, with five replications and 50 seedlings per experimental unit. The evaluated variables were: seedling height, root length, dry mass of the aerial part, root dry mass, number of secondary roots, stem diameter, leaf area and leaf area and survival rate in the field. Data were analyzed for variance and the means were compared by the Tukey test at 5% error probability. The substrates did not affect the evaluated variables, except for the number of secondary roots, where the commercial substrate was superior. The floating system was superior for all the variables evaluated, except for the sprouting in the field, which did not present differences. For leaf area the interaction was significant, where the combination of commercial substrate with the floating system produced the highest mean. These results show that the combination of floating system with vermin-compost is a viable alternative for the production of high quality tomato seedlings.

El experimento se llevó a cabo en el invernadero de producción de mudas del Centro Hortícola de la Facultad de Ciencias Agrarias, Universidad Nacional de Asunción, Paraguay, de septiembre a octubre de 2011. Se determinó la influencia del sistema flotante y tipos de substratos sobre el crecimiento de mudas de tomate (Lycopersicon esculentum Mill). Los tratamientos estuvieron constituidos por la combinación de dos sistemas de producción de mudas (flotante y convencional) y dos tipos de substratos (comercial y humus de lombriz). Se utilizó un diseño en bloques completos al azar con arreglo factorial 2 x 2, con cinco repeticiones y 50 mudas por unidad experimental. Las variables evaluadas fueron: altura de mudas, longitud de raíz, masa seca de la parte aérea, masa seca de raíz, número de raíces secundarias, diámetro del tallo, área foliar y porcentaje de sobrevivencia a campo. Los datos fueron sometidos al análisis de varianza y las medias comparadas por la prueba de Tukey al 5% de probabilidad de error. Los resultados indican que los substratos no afectaron las variables evaluadas, a excepción del número de raíces secundarias, donde el substrato comercial fue superior. El sistema flotante fue superior para todas las variables evaluadas, excepto prendimiento a campo, que no presentó diferencias significativas. Para área foliar la interacción fue significativa, donde la combinación del substrato comercial con el sistema flotante promovió la mayor media. Estos resultados muestran que la combinación del sistema flotante con humus de lombriz es una alternativa viable para la producción de mudas de calidad en tomate.

This research was conducted in order to assess the quality of seeds obtained from the germplasm collection of Jatropha curcas L. at the Centro Tecnológico Agropecuario en Paraguay (CETAPAR), located in the district of Yguazú, department of Alto Paraná, Paraguay. The treatments consisted of materials collected in Paraguay at the localities of Guayaki, Juan León Mallorquín, Minga Guazú, Caraguatay, La Colmena, Sapucai, Fulgencio R. Moreno, Santa Rosa del Aguaray and Horqueta; as well as accessions from the Brazilian state of Minas Gerais, whose names are Bento, Filomena, Gonzalo, Oracilia and from the state of Mato Grosso do Sul which bears the name of Dourados. Seed quality was evaluated by the average weight of thousand seeds, vigour, germination percentage and oil content. For all evaluated variables, statistical analyzes showed significant differences between treatments. Higher oil contents in seeds were found in the collections from Juan Leon Mallorquín, Guayaki and La Colmena, while Fulgencio R. Moreno had the highest vigour, germination and seed weight.

Esta investigación se llevó a cabo con el propósito de evaluar la calidad de semillas obtenidas de la colección de germoplasma de Jatropha curcas L. del Centro Tecnológico Agropecuario en Paraguay (CETAPAR), ubicado en el distrito de Yguazú, departamento de Alto Paraná, Paraguay. Los tratamientos estuvieron constituidos de materiales provenientes de colectas de las localidades paraguayas: Guayaki, Juan León Mallorquín, Minga Guazú, Caraguatay, La Colmena, Sapucai, Fulgencio R. Moreno, Santa Rosa del Aguaray y Horqueta; además de accesiones del estado brasileño de Minas Gerais, cuyas denominaciones son: Bento, Filomena, Gonzalo, Oracilia y Paraguaçu y de un material del estado de Mato Grosso do Sul, que lleva como nombre Dourados. La calidad de semillas fue evaluada según la masa de mil semillas, vigor, poder germinativo y el contenido de aceite. Los resultados estadísticos muestran que para todas las variables evaluadas existen diferencias entre los tratamientos. Los mayores contenidos de aceite en semillas se presentan en las colectas provenientes de Juan León Mallorquín, Guayaki y La Colmena; mientras que para el vigor, poder germinativo y peso de mil semillas, se destaca la procedente de Fulgencio R. Moreno.

Com o objetivo de avaliar a influência de bandejas de células na produção de tomate tipo italiano no campo, este trabalho foi realizado em Piracicaba (SP), Brasil, de maio a agosto de 2005. Os tratamentos consistiram de quatro volumes de recipiente, três bandejas de poliestireno expandido de 121,2; 34,6 e 12,0 cm³ e uma bandeja de plástico rígido de 14,0 cm³ (72, 128, 288 e 450 células, respectivamente), combinadas com quatro idades de transplante, 19, 24, 29 e 34 dias depois da semeadura. O delineamento para a produção das mudas foi inteiramente ao acaso, com cinco plantas por parcela e três repetições. Foram analisadas a área foliar, a altura da muda, a massa fresca e seca da parte aérea e da raiz, assim como a qualidade das mudas. No campo, o delineamento foi em blocos ao acaso com dez plantas por parcela e três repetições. Avaliaram-se a precocidade para início da colheita, a produção comercial e a produção total por planta. Nos recipientes de maiores volumes, foi observada a melhor qualidade de mudas (121,2 e 34,6 cm³). Quanto à produção de frutos, o número comercial e total de frutos por planta foi superior no transplante aos 24 dias, porém para a produção total de frutos, não houve diferença entre os tratamentos. Observou-se precocidade para a colheita nos tratamentos realizados nos volumes 121,2 e 34,6 cm³. O volume 14,0 cm³ (450 células) resultou em mudas de baixa qualidade, estioladas e raquíticas.

The aim of this study was to evaluate the influence of cell trays on the production of Italian type tomatoes (Lycopersicon esculentum Mill) in the field. This study was carried out in Piracicaba (SP), Brazil, from May to August 2005. The treatments consisted of four recipients with three expanded polystyrene trays, measuring 121.2; 34.6, and 12.0 cm³ and one tray of rigid plastic, measuring 14.0 cm³ (72, 128, 288 and 450 cells, respectively) combined with four vegetative ages at transplanting (19, 24, 29 and 34 days after sowing). A randomized experimental design was done for the production of seedlings, by using five plants per plot and three replications. The leaf area, the height, the fresh and dry mass of the aerial part and the root, and the quality of the seedlings were analyzed. In the field production, the statistical design was a randomized block, using ten plants in each row with three replications. Harvest precocity was evaluated, as well as the commercial and total production of each plant. The larger volume trays (121.2 and 34.6 cm³) caused the best quality of seedlings. On fruit production, the commercial and the total number of fruits per plant were superior in the seedlings of 24 days of age. However, there was no difference between the treatments for the total fruit production. The treatments performed in the recipients of 121.2 and 34.6 cm³ presented a gain in the harvest precocity. The tray cells of 14.0 cm³ (450 cells) provided poor quality, elongated and stunted seedlings.

Con el objetivo de evaluar la influencia de las bandejas de celdas sobre la producción de tomate tipo italiano en el campo, se realizó este trabajo en Piracicaba, SP, Brasil, de mayo a agosto del 2005. Los tratamientos consistieron en cuatro volúmenes de recipiente, tres bandejas de poliestireno expandido de 121,2; 34,6 y 12,0 cm³ y de una bandeja de plástico rígido de 14,0 cm³ (72, 128, 288 y 450 celdas, respectivamente) combinadas con cuatro edades para el trasplante (19, 24, 29 y 34 días después de la siembra). El delineamiento para la producción de mudas fue completamente al azar, con cinco plantas por parcela y tres repeticiones. Se analizaron área foliar, altura, masa verde y seca de la parte aérea y raíz y la calidad de las mudas. En la producción a campo, el delineamiento fue en bloques al azar con diez plantas por parcela y tres repeticiones. Fueron evaluadas la precocidad para inicio de cosecha, producción comercial y total por planta. Volúmenes mayores de recipiente (121,2 y 34,6 cm³) presentaron mejor calidad de mudas. En la producción de frutos, el número comercial y total de frutos por planta fue superior en la muda de 24 días de edad, sin embargo, en la producción total de frutos, no hubo diferencia entre los tratamientos. Por otro lado, también se obtuvo precocidad para la cosecha en los tratamientos realizados en los volúmenes de 121,2 y 34,6 cm³. El volumen de recipiente de 14,0 cm³ (450 celdas) resultó en mudas de calidad muy inferior, alongadas y raquíticas.

A endogamia reduz o vigor em plantas pela diminuição da proporção de loci heterozigotos. Entretanto, a influência da endogamia é diferente entre as espécies. O objetivo deste trabalho foi avaliar a depressão causada por endogamia em uma população de pepino do tipo japonês. A partir do intercruzamento entre plantas do híbrido Natsu suzumi foi obtida a geração F2, considerada como população S0. Obtiveram-se progênies S1, S2, S3, S4 e S5, através de autofecundações sucessivas pelo método do SSD ('Single Seed Descent'). Foram sete tratamentos (híbrido Natsu suzumi, populações S0 a S5) e o delineamento experimental foi em blocos ao acaso, com seis repetições e cinco plantas por parcela cultivadas em ambiente protegido de 21/08/2002 à 29/11/2002. Foram avaliados o número de folhas, semanalmente, o número e a massa de frutos, total e comercial, número de nós e porcentagem de nós com brotações laterais. Na comparação entre as populações S0 a S5 não foram observadas diferenças para todas as características avaliadas demonstrando não haver perda de vigor por endogamia nesta população.

Inbreeding reduces the vigor in plants as a result of a decrease in the proportion of heterozygous loci. However, the influence of inbreeding is different among the species. The objective of this work was to evaluate the inbreeding depression in a cucumber Japanese population. An F2 population was obtained from a commercial hybrid (Natsu suzumi), which was considered as S0 population. S1, S2, S3, S4 and S5 progenies were obtained by the 'Single Seed Descent' methodology. A complete blocks design with seven treatments (different generations of self pollination - S0 to S5 and the hybrid Natsu suzumi), and six replications of five plants per plot was used in protected cultivation from Aug. 21 to Nov. 29, 2002. Number of leaves, length of the main stem, number and weight of fruits (total and commercial) number of nodes and vines percentage were evaluated. For most of the traits appraised differences were not observed among populations showing that there was no loss of vigor due to inbreeding in this population.

Este trabalho teve por objetivo verificar se existe depressão por endogamia para produção de sementes com sucessivas gerações de autofecundações em uma população de pepino caipira, obtida a partir da geração F2 do cruzamento (Safira x Hatem) x Safira. O delineamento experimental utilizado foi em blocos ao acaso, com seis tratamentos (diferentes gerações de autofecundação - S0 a S5), quatro repetições e cinco plantas por parcela. Não houve diferença estatística para todas as características avaliadas (número de frutos por planta, massa de sementes por planta, massa de sementes por fruto, número de sementes por planta, número de sementes por fruto, massa de 100 sementes, teste-padrão de germinação, primeira contagem do teste-padrão de germinação e índice de velocidade de germinação), observando-se que a endogamia não afetou a produção e qualidade das sementes nessa população.

The objective of this work was to evaluate the inbreeding depression after successive generations of self-pollination in a cucumber population, generation F2 from the cross (Safira x Hatem) x Safira. Experimental design was randomized blocks with six treatments (different generations of self-pollination - S0 to S5), four replicates and five plants per plot. There was no statistical difference among all evauated characteristics (fruit number per plant, number and weight of seeds per plant and per fruit, germination test, first count of germinated seeds, index of germination a and weight of 100 seeds), showing that inbreeding did not affect seed production and quality in this population.