Acta Agronómica

**Groups of floral visitors insects of the litchi (Litchi chinensis Sonn.) in Jaboticabal, São Paulo State, Brazil.**

Os objetivos deste estudo foram identificar grupos de insetos visitantes de flores da lichieira (Litchi chinensis Sonn.), determinar horários de maior visitação, analisar a influência da altura das inflorescências na ocorrência desses visitantes florais e verificar se a incidência de sol beneficia sua presença. O experimento foi desenvolvido na Faculdade de Ciências Agrárias e Veterinárias da Universidade Estadual Paulista FCAV/UNESP. As observações ocorreram em agosto e setembro de 2008, totalizando cinco em todo o período. Foram estabelecidos dois períodos diários de observação das 10:00 às 12:00 h e 16:00 às 18:00 h, sendo observado quatro pontos na área. Os dados dos visitantes florais observados para as diferentes horas, alturas e radiação solar foram submetidos à análise de variância e as médias foram comparadas pelo teste de Tukey 5%. Foram observadas seis ordens de insetos: Hymenoptera, Diptera, Hemiptera, Coleoptera, Lepidoptera e Neuroptera. O horário das 10:00 às 12:00 horas apresentou- se como mais propício para observação de insetos visitantes. Houve diferença nas observações das alturas de 0 a 0.5 e 1.6 m e 2.0 e também uma diferença nas observações de insetos visitantes florais da lichieira quando estas se encontravam em face sombra ou face sol na árvore.

The objective of this study was to identify the groups of insects that are found visiting flowers of litchi, to determine the time of the visits, to analyze the influence of the inflorescence height in the occurrence of floral visitors and to verify if the incidence of sunlight benefits the visits. The experiment was corried in Faculdade de Ciências Agrárias e Veterinárias da Universidade Estadual Paulista, FCAV/UNESP. The observations were made in August and September 2008, totaling five observations in the whole period. Two observation periods were established for each day: 10:00am to 12:00am and 4:00pm to 6:00pm, and we observed four points within the orchard. The data of floral visitors noted to different hours, heights and sunlight were subjected to analysis of variance and the means were compared by Tukey 5%. Six orders of insects were observed: Hymenoptera, Diptera, Hemiptera, Coleoptera, Lepidoptera and Neuroptera. The time from 10:00 to 12:00 was the most favorable for observation of insect visitors. There were differences in the heights observations from 0.0 to 0.5 and 1.6 to 2.0 meters. There was also a difference in the observations of insects visiting the flowers of litchi when they faced the sun or were shaded.

**Pulp of camu-camu (Myrciaria dubia) subjected to gamma radiation**

O fruto amazônico camu-camu, Myrciaria dubia, possui elevado teor de vitamina C, antocianinas, carotenóides e compostos fenólicos, fatores que fazem com este fruto venham se posicionando na preferência dos consumidores de frutas exóticas. A radiação ionizante tem sido utilizada para aumentar a vida útil dos produtos, além de preservar qualidades intrínsecas e nutricionais. Desta forma, o objetivo deste trabalho foi estudar a radiação gama como método alternativo na conservação da polpa de camu-camu. As amostras de polpa do fruto foram submetidas às doses 0 (controle), 2, 4, e 6 kGy. Em seguida, foram armazenadas a 6 ºC e à temperatura ambiente (26 ºC), e avaliadas quanto a cor, pH, acidez titulável, teores de sólidos solúveis, vitamina C, compostos fenólicos e antocianinas nos períodos 1 e 15 dias de armazenamento. Os atributos pH, teor de sólidos solúveis, compostos fenólicos e acidez total, não foram afetados pela irradiação e pela temperatura de armazenamento nos dois períodos analisados. A vitamina C também não se alterou com a irradiação, porém o armazenamento refrigerado manteve os teores mais constantes. A cor foi o atributo mais afetado pela irradiação e pelo armazenamento à temperatura ambiente. Portanto, a radiação gama não se mostrou eficaz no armazenamento da polpa desta fruta em nenhuma das temperaturas propostas.

The Amazonian fruit camu-camu, Myrciaria dubia, has a high content of vitamin C, anthocyanins, carotenoids and phenolic compounds, factors that make this fruit will be positioned in the consumer preference of exotic fruits. Ionizing radiation has been used to extend the life of the products, while preserving the intrinsic qualities and nutritional. Thus, the aim was to study the gamma radiation as an alternative method in preserving the pulp of camu-camu. The pulp of the fruit samples were subjected to doses 0 (control), 2, 4 and 6 kGy. They were then stored at 6 ºC and at room temperature (26 ºC), and evaluated as to the color, pH, titratable acidic, soluble solids, vitamin C, phenolic compounds and anthocianins in periods 1 and 15 days of storage. The pH, soluble solids, total acidity attributes and phenolic compounds were not affected by irradiation and storage temperature in both periods analyzed. Vitamin C also did not change with irradiation, but the cold storage levels remained more constant. The color was the most affected attribute by irradiation and storage at room temperature. Therefore, gamma radiation was not effective in storage of the pulp of this fruit in any of the proposed storage temperatures.

**Phytase activity and comparison of chemical composition, phytic acid P content of four varieties of quinoa grain (Chenopodium quinoa Willd.)**

Quinoa (Chenopodium quinoa Willd.), is a plant that has been cultivated in the Andean region of Bolivia, Peru, Ecuador and Colombia. Its importance is due to the high proteins content and essential amino acids of its grain. The aim of this research was to investigate the relations between phytic acid P content and phytase activities of varieties quinoa Nariño-Colombia (QC), quinoa Anapqui's-Bolivia (QBA), quinoa -IICA 020 Oruro-Bolivia (QB) and quinoa Huancavelica-Peru (QP). We found significant differences in the proportions of protein, fat, fibre, and ash among the four varieties. The analysis of essential amino acids showed that these varieties were rich in arginine, leucine, phenylalanine, lysine and valine, and tyrosine a semi essential amino acids. The fat fraction of all varieties contained high concentration of oleic acid, linoleic acid, a-linolenic acid and palmitic acid. The varieties were rich in phosphorus and calcium. The phytic acid P proportion in total P, in the QC (19,64%) was significantly lower than in other three varieties. In the variety QC (1052 FTU/kg) we found high concentration of phytase. A significant negative correlation (r=-0.89) was found between the concentration of phytase activity and phytic acid P among the four varieties.

Quinua (Chenopodium quinoa Willd.) es una planta que ha sido cultivada en las regiones andinas de Bolivia, Perú, Ecuador y Colombia. Su importancia se debe al alto contenido de proteínas y de aminoácidos esenciales en su grano. El objetivo principal en la investigación fue encontrar la relación entre el ácido fítico y la actividad de la fítasa en las variedades de quinua Nariño procedente de Colombia (QC), quinua Anapquis (QBA) y quinua -IICA 020 Oruro (QB) procedentes de Bolivia, y quinua Huancavelica de Perú (QP). Se encontraron diferencias significativas en las proporciones de proteína, grasa, fibra y ceniza entre las cuatro variedades. El análisis de los aminoácidos esenciales mostró que las variedades de quinua tienen altas concentraciones de arginina, leucina, fenilalanina y lisina, y tirosina como aminoácidos semi-esenciales. La fracción de grasa presentó concentraciones altas de ácido oleico, linoleico, a-linolénico y ácido palmítico. Las variedades presentaron altos contenidos de P y Ca. El ácido fítico en QC (19.64%) fue significativamente más bajo que en las otras variedades. En la variedad QC (1052 FTU/kg) se encontraron altas proporciones de actividad de la fítasa. Se encontró relación significativa y negativa (r = -0.89) entre la actividad de la fítasa y el ácido fítico en todas las variedades.

**Photochemical efficiency of photosystem II and growth in banana passionfruit plants (Passiflora tripartita (Juss.) var. mollissima (Kunt) L.H. Bailey under salt stress**

Banana passionfruit (Passiflora tripartita (Juss.) var. mollissima (Kunth)) is an important crop in Colombia, with Boyacá Department contributing over half of national production. Osmotic stress is a major hindrance to production of this crop, but there exists little information on banana passionfruit responses to soil salinity. The present study aimed to evaluate growth and chlorophyll fluorescence in banana passionfruit under salt stress. A completely randomized block design was used. Plants were exposed to concentrations of 20, 40, 60, and 80 mmol NaCl kg-1 soil. Leaf area was reduced by 20.89, 42.91, 58.37, and 76.40%, respectively, compared to control plants in non saline conditions. Total stem length showed a reduction of 9.97, 27.28, 42.79, and 55.77%, and total dry weight per plant was reduced by 23.89, 31.49, 39.60, and 61.26%. Maximum quantum yield of photosystem II (Fv/Fm) was reduced by 11.29, 14.23, 38.89, and 92.25% under the respective treatments. Salinity thus affected all measured growth factors and photosynthesis drastically. Leaf area reduction was closely correlated to reduction in photosynthesis. Dry matter reduction also closely followed the trend in Photosystem II maximum quantum yield (Fv/Fm), which suggests that the major impact of salinity on the banana passionfruit plants was due to negative effects on photosynthesis.

La curuba (Passiflora tripartita (Juss.) var. mollissima (Kunth)) es un cultivo importante en Colombia, especialmente en el departamento de Boyacá. A pesar de que el estrés osmótico es un limitante en la producción de este cultivo, existe poca información sobre su respuesta a la salinidad. En el presente estudio se evaluó el crecimiento y la fluorescencia de la clorofila en plantas de curuba bajo estrés salino. Las plantas se expusieron a concentraciones (mmol/kg de suelo) de 20, 40, 60, y 80 de NaCl. Como consecuencia, el área foliar de la planta se redujo 20.89, 42.91, 58.37 y 76.40%, respectivamente, en relación con plantas control (condiciones no salinas). La longitud total de tallos se redujo 9.97, 27.28, 42.79 y 55.77% y el peso seco total por planta en 23.89, 31.49, 39.60 y 61.26%. La eficiencia cuántica máxima del fotosistema II (Fv/Fm) se redujo 11.29, 14.23, 38.89 y 92.25% bajo los tratamientos de salinidad; por tanto, la salinidad afectó drásticamente los parámetros de crecimiento y fluorescencia. La reducción en el área foliar se correlacionó con la reducción en la fotosíntesis. La reducción en peso seco también siguió la tendencia de la relación Fv/Fm, lo que sugiere que la mayoría de los impactos de la salinidad en las plantas de curuba se deben a los efectos negativos sobre la fotosíntesis.

**Evaluation of cultivation media for in vitro propagation of seeds and explants from wild Solanum species**

Se evaluaron los medios de cultivo Hussey-Stacey (A), Hendrix et al. (H), Atkinson et al. (AT) y mitad de Murashyge y Skoog (½MS) para la propagación in vitro de semillas y explantes de Solanum mammosum, S. marginatum, S. hirtum y S. umbellatum. En la fase de propagación sexual se evaluó el porcentaje de germinación, número de raíces, longitud de planta, días a formación de hojas y raíces, días a morfogénesis completa y materia seca. Se determinó el tipo de morfogénesis a través de callos, vástago y plantas totalmente formadas. Se estudiaron el número y longitud de brotes, número de raíces y hojas, producción de materia seca y días a morfogénesis completa. Para S. mammosum el mejor medio de germinación fue ½MS, para el desarrollo de plantas fue A y para propagación vegetativa, A-Nudos (Medio A con explantes tipo nudos). En el mismo orden, para S. marginatum fueron los medios A, H y ½MS y/o H con nudos, mientras que en S. hirtum fueron H,A y H-nudos. Para S. umbellatum no se encontraron diferencias en germinación entre H, ½MS y A. Para la formación de plantas el mejor medio fue ½ MS y para propagación vegetativa fue H-Nudo.

Hussey, Stacey (A), Hendrix et al, (H), Atkinson et al, (AT) and half Murashyge and Skoog (½ MS) cultivation media were evaluated for in vitro propagation of seeds and explants of Solanum mammosum, S. marginatum, S. hirtum and S. umbellatum. During the sexual propagation phase the germination percentage, root number, length of plant, days to formation of leaves and roots, complete morphogenesis days and dry matter was evaluated. The morphogenesis type was determinated through callus, stem and fully formed plants. Number and length of shoots, number of roots and leaves, dry matter and morphogenesis days were studied. For S. mammosum the best germination medium was ½ MS, for the development of plants was A and for vegetative propagation, A-KNOTS. In the same order as for S. marginatum are media A, H and ½ MS and/or H knots, while in S. hirtum are H,A, and H-knots. For S. umbellatum there were not significant differences between H, ½ MS and A in germination. For the formation of plants was ½ MS and vegetative propagation H-Knot.

**Model to estimate the leaf area of Combretum leprosum Mart.**

Combretum leprosum Mart. -Combretaceae é um arbusto usado na medicina popular do nordeste brasileiro como antiúlcerogênica, antihemorragica e antinociceptiva. Estimativa da área foliar é uma importante observação biométrica a ser feita para comparar o crescimento das plantas. Neste estudo, um modelo de cálculo da área foliar foi desenvolvido para Combretum leprosum, utilizando medidas lineares de comprimento de folha (C) e a largura máxima (L), com o objetivo de obter uma equação através de parâmetros lineares dimensionais das folhas. Foram coletados 200 limbos foliares de uma população de C. leprosus nativa em uma área conservada de Caatinga dentro do campus da Universidade Federal Rural do Semi árido em Mossoró, Rio Grande do Norte. As folhas foram obtidas de indivíduos adultos e a área das folhas foi determinada através de um integrador de área foliar (LI-3100, LI-COR). A analise de variância da regressão foi feita no programa SAEG. As equações lineares simples, exponenciais e geométricas obtidas podem ser usadas para estimação da área foliar de C. leprosum. Do ponto de vista prático, sugere-se optar pela equação linear simples que envolve o produto C x L, usando-se a equação de regressão A = 0.7103 x (C x L), que equivale a tomar 71.03% do produto entre o comprimento ao longo da nervura principal e a largura máxima, com um coeficiente de determinação (R²) de 0.952617.

Combretum leprosum Mart. -Combretaceae es un arbusto utilizado en la medicina popular del noreste de Brasil como antiulceroso, antihemorrágica y antinociceptiva. En este estudio se desarrolló un modelo para el cálculo de área foliar de Combretum leprosum usando mediciones lineales de longitud (C) y ancho máximo (L) de la hoja. Se recolectaron 200 láminas de hojas de una población de C. leprosum nativo en un área de conservación de la Caatinga en el campus de la Universidad Federal Rural de la Semi árido en Mossoro, Rio Grande do Norte. Las hojas se obtuvieron de árboles adultos y el área foliar se midió utilizando un integrador (LI-3100, LI-COR). El análisis de regresión se hizo con el programa SAEG. Para estimar el área foliar de C. leprosum se puede utilizar la ecuación lineal simple de regresión A = 0.7103 x (C x L), que es equivalente a tomar 71.03% de los productos de la longitud a lo largo de la nervadura central y el ancho máximo, con un coeficiente de determinación de 0.952617.

Combretum leprosum Mart. -Combretaceae is a shrub used in popular medicine in Northeast Brazil as antiulcer, antihemorragica and antinociceptive. Estimating the leaf area is an important remark to be made biometric to compare the growth of plants. In this study, a model for calculating leaf area was developed for Combretum leprosum using linear measurements of leaf length (C) and maximum width (L), in order to obtain an equation by the linear dimensions of the leaf. It was collected 200 leaf blades of a population of C. leprosum native in a conservation area of Caatinga in the campus of the Federal Rural University of the Semi Arid in Natal, Rio Grande do Norte. The leaves were obtained from adults and leaf area was measured using an integrator leaf area (LI-3100, LI-COR). The analysis of variance of the regression was made in the program SAEG. The linear and geometric equations can be used to estimate leaf area of C. leprosum. From a practical standpoint, it is suggested to opt for the simple linear equation involving the C x L, using the regression equation A = 0.7103 x (C x L), which is equivalent to taking 71.03% of product of the length along the midrib and the maximum width, with a coefficient of determination of 0.952617.

**A coupled model of stomatal conductance, photosynthesis and transpiration for passionfruit (Passiflora edulis) cultivars**

En la actualidad se desconocen las respuestas de los cultivos en términos de balances hídrico y energético frente al aumento de gases efecto invernadero y cambio climático. El objetivo de este trabajo fue formular y evaluar un modelo acoplado de fotosíntesis, conductancia estomática y transpiración para el cultivo de maracuyá (Passiflora edulis) en condiciones de clima tropical por medio de la combinación de submodelos ampliamente aceptados. Como caso de estudio se utilizó el protocolo de modelación matemática aplicado al cultivo en el departamento del Huila, Colombia. La transpiración real estimada por el modelo fue evaluada usando un lisímetro de tipo gravimétrico. Los resultados del estudio indicaron que el modelo propuesto fue capaz de estimar la transpiración del cultivo de maracuyá bajo condiciones de clima templado con una buena validación de 0.30. La transpiración media diaria para el cultivo en las condiciones de clima templado del departamento del Huila durante el periodo de estudio fue de 1.36 mm/día. Por análisis de sensibilidad se identificó el parámetro m siendo altamente sensible para el caso de estudio; por el contrario, los parámetros Vm25, Kc25, Jm25, Ko25, f, Bs mostraron escasa sensibilidad e identificación.

At present, crop behavior due to climate change is not well known, in particular those responses related to water and energy balances. The aim of this work was to propose and implement a model aimed to evaluate interactions among photosynthesis, stomatal conductance and transpiration phenomenon under both crop growing process and tropic climate conditions. A passion fruit crop located in Colombia (Huila Department) is taken as a study case. The actual transpiration estimated by the model was evaluated using a gravimetric type lysimeter. The results indicated that the proposed model was able to estimate the passion fruit crop transpiration under conditions in the tropic climate with a good validation of 0.30. The mean daily transpiration rate under wet weather conditions during the study period was 1.36 mm d-1.Sensitivity analysis indicated that the parameter m is identified and is highly sensitive for the case study, however, VM25, KC25, JM25, Ko25, f, B parameters showed poor sensitivity and identification.

**Interaction among Tsukamurella paurometabola C-924 and Rhizobium leguminosarum biovar phaseoli CFH in bean plants**

En el estudio se evaluaron, mediante análisis de los parámetros fenológicos de las plantas, la interacción de Tsukamurella paurometabola C-924 con Rhizobium leguminosarum biovar phaseoli CFH en el cultivo de frijol. Se emplearon cuatro tratamientos: plantas sin inocular (control), inoculadas con T. paurometabola C-924, inoculadas con R. leguminosarum biovar phaseoli CFH e inoculadas con ambas cepas. Se observaron diferencias significativas (P < 0.01) en los porcentajes de germinación de las plantas tratadas con microorganismos de forma independiente o conjunta con respecto al control sin inocular. Se determinó que la inoculación de T. paurometabola C-924 afectó el proceso de nodulación de R. leguminosarum biovar phaseoli CFH. Sin embargo, esto no incidió de manera significativa en la altura de las plantas ni en el diámetro del tallo, ya que no se encontraron diferencias entre los tratamientos para estos parámetros. Para el número de hojas, los mejores resultados se obtuvieron con la aplicación de T. paurometabola C-924. Se concluyó que la interacción de T. paurometabola C-924 con R. leguminosarum biovar phaseoli CFH en el frijol estimuló significativamente la germinación de las semillas y el número de hojas de las plantas con respecto al control sin inocular. Aunque la aplicación de T. paurometabola C-924 no favoreció la nodulación de R. leguminosarum biovar phaseoli CFH, esto no afectó las características fenológicas del cultivo.

The experiment was carried out to evaluate the interaction between Tsukamurella paurometabola C-924 and Rhizobium leguminosarum biovar phaseoli CFH in bean plants. Treatments consisted of non-inoculated plants (control), plants inoculated with T. paurometabola C-924, inoculated with R. leguminosarum biovar phaseoli CFH and inoculated with both strains. The application of the microorganisms single or in coinoculation improved the germination of seeds. T. paurometabola C-924 did not enhanced Rhizobium nodulation. However, no significant differences were found among treatments for shoot height and diameter. There was an increase in number of leaves in the plants inoculated with T. paurometabola C-924. We concluded that the interaction between T. paurometabola C-924 and R. leguminosarum biovar phaseoli CFH improved the number of leaves and the germination of seeds and even though T. paurometabola C-924 did not enhance nodulation, this fact did not affect the plants growth.

Supplementation and iron metabolism in bovine calfs in tropical conditions

Se estudió el efecto del suministro de hierro en la dinámica hemática y su metabolismo en terneros; para el efecto se seleccionaron 72 neonatos bovinos pertenecientes a tres grupos raciales: dos de origen Bos taurus (Hartón de Valle y Holstein Friesian) y uno de origen Bos indicus (Cebú Brahmán) para un total de 24 animales por raza y ocho animales por grupo experimental. Los animales del grupo 1 recibieron 500 mg de hierro dextran intramuscular (T1), al grupo 2 se le suministraron 100 mg de espirulina oral (T2) y el grupo 3 permaneció como control (T3). El suministro de hierro se hizo cada mes desde el nacimiento hasta los 6 meses de edad de los terneros, mensualmente se tomaron muestras de sangre mediante venipunción yugular y sistema vacutainer en tubos con y sin anticoagulante (EDTA). El promedio de ganancia de peso vivo animal fue 509 ± 0.40 g/día. El número de leucocitos/mm³ fue de 16,059. El promedio de hemoglobina en sangre fue de 12.11 ± 2.8 g/dl, el hematocrito presentó un valor de 38.4% ± 7.6 y la concentración promedio de hemoglobina corpuscular fue de 31.62% ± 4.7. La proteína sérica presentó un valor promedio de 5.55 ± 0.7 g/dl, el valor promedio de hierro sérico fue de 18.70± 11.8 µmol/lt. Los análisis estadísticos mostraron que el factor mes de muestreo y raza fueron significativos para los valores séricos de los metabolitos analizados, mientras que los valores de la concentración promedio de hemoglobina corpuscular lo fueron para tratamiento (P < 0.01).

72 calves were selected in growth phase which belonged to three breeds groups, two of origin Bos taurus and one of origin Bos indicus. Three treatments were subjected in each one of breeds (8 animals per group), one group was injected with 500 mg of Iron Dextran (intramuscularly), and the other was 100 mg oral Spirulina and a third was defined as the control group. The main idea of this research was study metabolism dynamics in hematic and iron under the effect of two supplements. The experimental period lasted the first six months of life of the calves. Samples for hematic analysis were collected by jugular venipuncture technique in vacutainer tubes with anticoagulant (EDTA) and others tubes without it. Using commercial reagents for specific colorimetric techniques for serum iron and hemoglobin were analyzed. Total protein was analyzed by direct reading refractometer. The average of weight gain was 509 ± 0.40 g/d. Cell count showed 16059.96 leukocytes by mm³. Hemoglobin showed value of 12.11g/dl ± 2.8 whereas the hematocrit had a value of 38.40 % ± 7.6 and the corpuscular hemoglobin concentration showed a mean value of 31.62% ± 4.7. Serum protein showed a mean value of 5.55 g/dl ± 0.7 and the serum iron mean value was 18.70 µmol/L ± 11.8. Statistical analysis of variance showed that the month factor sampling and the breed factor of all analyzed metabolites showed significant differences for serum levels, whereas the treatment factor of showed statistical differences only mean corpuscular hemoglobin concentration values.

Effect of agrochemicals on soil microorganisms of a rice culture

En un Oxisol de los Llanos Orientales de Colombia, en condiciones de campo se evaluó el efecto de la aplicación de agroquímicos sobre los microorganismos presentes en un cultivo de arroz secano. Los agroquímicos evaluados fueron Glifosato, Bispiribac, Azoxystrobin y Malatión, aplicados en dosis comerciales, en un diseño experimental de bloques con medidas repetidas. Para el recuento de microorganismos se tomaron muestras compuestas de suelo rizosférico usando la metodología de transectos. A partir de las muestras fueron realizados conteos microbianos empleando dilución en placa y los datos se analizaron empleando análisis de varianza y prueba de comparaciones múltiples. En los conteos se encontraron bacterias Gram (+), Gram (-), actinomicetos, y los grupos funcionales fijadores de nitrógeno y solubilizadores de fósforo, junto con los hongos Trichoderma spp., Fusarium spp. y Penicillium spp. Los hongos, los actinomicetos y los solubilizadores de fósforo fueron los microorganismos más afectados por los agroquímicos, con reducciones en la abundancia. Las bacterias presentaron comportamientos variables dependiendo del agroquímico y los fijadores de nitrógeno fueron estimulados por los tratamientos. Estos resultados indican que los agroquímicos utilizados en el estudio pueden impactar de diferente manera los microorganismos que se encargan de la descomposición de la materia orgánica.

This paper show an analysis of the effect of agrochemicals used in a rice crop on the abundance of Oxisol soil microorganisms in the region of the Eastern Plains of Colombia, under field conditions. Evaluated Agrochemicals were Glyphosate, Bispiribac, Azoxystrobin and Malathion, applied in commercial dosages, in a block design with repeated measures. For the enumeration of microorganisms, soil samples were taken from rhizospheric soil using the transects methodology. From the samples, microbial counts were carried out using the method of dilution in plate and the data were analyzed using the Minitab 14 software using analysis of variance and test for multiple comparisons. In the counts bacteria Gram (+), Gram (-), actinomycetes, and functional groups: nitrogen fixers, and phosphorus solubilizing, together with the fungus, Trichoderma spp., Fusarium spp., and Penicillium spp. were found. In general, fungi, actinomycetes and the phosphorus solubilizing microorganisms were more affected by the agrochemicals with reductions in their abundance. Bacteria presented varying behaviors depending on the agrochemical and the nitrogen fixers were stimulated by the treatments. These results indicate that the chemicals may impact in different ways to the microorganisms that are responsible for the decomposition of organic matter.

**Generation mean analysis to estimate genetic parameters in a cross of pimenton and cayenne pepper (Capsicum annum L.)**

El peso de frutos por planta es una característica compleja y controlada por múltiples genes donde el ambiente interfiere en la manifestación fenotípica. La estimación de componentes génicos como los de interacción epistática es de gran importancia en el proceso de mejoramiento genético de una especie. El objetivo de este estudio fue la estimación de parámetros genéticos para el peso del fruto por planta, usando un análisis de medias generacionales (P1, P2, F1, F2, RCYield is a complex trait and is under the control of multiple genes in which the environment interfere on the phenotype. The estimation of genetic components, including non-allelic interactions acquire a great importance on the breeding of a crop. The objective of this study was to estimate the genetic parameters for yield, using generation means analysis (P1, P2, F1, F2, BC1 and BC2) derived from the cross of Pimenton Serrano and Aji Cayenne 958 (inbreed lines of Capsicum annuum). The analysis revealed that additive, dominance and the non-allelic interactions components were significantly for the phenotypic expression, indicating the need for a four-parameters model.Additive by additive [i] effects revealed significance for fruit weight. Recessive or double recessive epistasis, was found. Finally, a breeding program based on recurrent selection to increase the average yield in a pepper (Capsicum annuum) population can be used, due to the epistatic interaction can be effectively exploited through the hybridization among promissory lines.