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O cultivo de hortaliças tem grande importância socioeconômica, e a Bidens pilosa L. é uma planta daninha com efeito alelopático que pode diminuir a germinação de sementes de hortaliças e prejudicar seu desenvolvimento inicial. Com este estudo objetivou-se determinar a potencialidade alelopática de picão-preto sobre a germinação e desenvolvimento inicial de sementes de alface e almeirão. Foram conduzidos dois ensaios separadamente, um com sementes de alface e outro com sementes de almeirão. Os testes de germinação e vigor foram conduzidos em placas de petri e dispostos em delineamento inteiramente casualizado, com quatro concentrações de extrato aquoso de picão-preto (0, 20, 60 e 100%) e cinco repetições, totalizando 20 parcelas experimentais. As características avaliadas foram: número de dias para início de germinação, número de dias para finalizar a germinação, porcentagem de germinação, índice de velocidade de germinação, tempo médio de germinação, comprimento da raiz e do hipocótilo. O número de dias para iniciar a germinação e o tempo médio de germinação de sementes de alface e almeirão foram maiores, à medida que aumentou a concentração de extratos aquosos de picão-preto. Com o aumento das concentrações de extrato, o percentual germinativo, o índice de velocidade de germinação, o comprimento da raiz e do hipocótilo de plântulas de alface e almeirão foram reduzidos. O extrato aquoso de folhas de picão-preto apresentou atividade alelopática inibitória sobre a fisiologia da germinação e o desenvolvimento de plântulas de alface e almeirão.

Lettuce is a leafy vegetable traditionally cultivated by family farmers who employ sustainable techniques in their cultivation, such as the use of alternative solutions for fertilization, seeking resources available on the properties, such as cow urine in nitrogen fertilization. The use of materials is fundamental to promote the sustainability of agriculture and the conservation of the environment, reducing nutrient losses and optimizing their use. The cultivation of plants in greenhouses can provide an increase in their production and productivity, in view of the environment better controlling climatic factors. In view of the above, the present work aimed to evaluate the productive performance of the (Maravilha, Romana, Romana white, Regina and Regina de Verão) lettuce varieties, submitted to the application of cow urine via soil in a protected environment. The variables number of leaves (NF), plant height (AP), average diameter (DM); shoot green mass, shoot dry mass, root green mass and root dry mass. Cow urine provided better results for all demonstrated varieties, with Regina having the best performance for NF and DM and the white Romana variety having the best results for the other variables. Cow urine, as a natural fertilizer, applied via soil, is an alternative to increase the development and growth of lettuce. [ABSTRACT FROM AUTHOR]

The use of plant growth-promoting microorganisms is an alternative to reduce costs with mineral fertilizers and increase sustainability in agriculture. This study aimed to investigate the effect of co-inoculation with plant growth-promoting bacteria and arbuscular mycorrhizal fungi on the growth and yield of lettuce under reduced NPK fertilization and greenhouse conditions, using five treatments (100 % of fertilization; 50 % of fertilization; 50 % of fertilization + Azospirillum brasilense inoculation; 50 % of fertilization + Rhizophagus clarus inoculation; 50 % of fertilization + co-inoculation), with eight replications. The inoculation with R. clarus increased plant height by 79.5 %, while, for A. brasilense, this increase reached 68 %, as compared to NPK fertilization. The single inoculation of both microorganisms increased the stem mass, but only A. brasilense was associated to the higher number of leaves, although it was not accompanied by an increase in the fresh and dry leaf matter. The co-inoculation increased the leaf fresh matter by 24.6 % and the number of leaves by 25.3 %.

Na última década, após a normatização para uso de remineralizadores na agricultura, diversos estudos têm confirmado efeitos positivos desses produtos nos sistemas agrícolas, sendo esses efeitos mais intensivos em rochas vulcânicas básicas, como o pó de basalto. Nesse contexto, essa pesquisa teve por objetivo avaliar o efeito de um pó de basalto filler sobre o crescimento das culturas de alface e repolho e sobre os indicadores químicos do solo. O experimento foi conduzido em casa de vegetação, em vasos, em um delineamento completamente casualizado em um fatorial 2x4x2, sendo dois tipos de solo (Cambissolo e Neossolo quartzarênico), quatro doses de pó de basalto (0, 5, 10 e 20t ha-1) com e sem adubação solúvel, com quatro repetições. Houve interação entre os fatores para todos os indicadores avaliados. O pó de basalto filler foi efetivo em aumentar a produção de massa seca das culturas quando cultivado em Neossolo quartzarênico até a dose de 10t ha-1. Nas duas culturas houve correlação negativa entre pó de basalto e a adubação solúvel. No solo, 115 dias após a incorporação das doses e após o cultivo de alface e repolho, o pó de basalto filler foi eficaz em alterar os atributos do solo, sendo esse efeito mais acentuado no Neossolo. Em ambos os tipos de solos houve aumento quadrático no pH e nos teores de fósforo (P), potássio (K), cálcio (Ca) e na saturação de bases (V%) de acordo com o aumento das doses do produto. Os resultados indicam potencial promissor do produto para uso na agricultura.

ABSTRACT: In order to ensure reliable inferences in scientific experiments, sampling criteria should be determined and defined during the experimental design phase. Determining plot and sample sizes without scientific criteria could result in resource and labor inefficiencies with no gain in experimental precision. In this work we estimate plot and sample sizes for biometric variable analyses in lettuce seedlings. The seedlings were sown in four expanded polystyrene foam transplant trays with 128 and 200 cells. Foliar area, stem diameter, shoot height, root length, root volume, root area, fresh and dry shoot and root masses. The methods described by Paranaiba (PARANAIBA et al., 2009) and Cochran (COCHRAN, 1977) were used for plot size and sample size estimations, respectively. Sample size varied according to the variables analysed and transplant tray cell number. Root variables required the highest number of samples. For a 10% margin of error, 12 seedlings were necessary for evaluations in a 128 cell tray, while 11 seedlings were required for analysis in 200 cell trays.

The objective was to determine the appropriate dose of liquid peat and compare substrates in the development of lettuce cultivars. Two experiments were carried out in the municipality of Vilhena-RO. The doses of liquid peat used were 0, 1, 2, 3 and 4%, with four applications being made after the fifth day of emergence, with an interval of five days. The design adopted in each experiment was completely randomized in a 2x5 factorial scheme, with two types of substrates (Vivatto Slim Plus® and Carolina Soil®) and five doses of peat, with four replications each, such as experiment (The cultivars were Grands Rapids and Cinderella). After the 25th day of emergence of each lettuce cultivar, the seedlings were evaluated for: shoot green mass (MVPA), root green mass (MVR), total green mass (MVT), seedling height (ALT), shoot dry mass (MSPA), root dry mass (MSR), total dry mass (MST), stem diameter (DIAM), root size (ROOT). The application of up to 1% of liquid peat proved to be superior to other doses when applied to Carolina and Vivatto substrates in relation to MSPA and MST. The application of 1% liquid peat proved to be superior to other doses when applied to the Vivatto substrate in relation to MVPA, MVR and MVT. It is concluded that for cv. Grand Rapids, it was observed that the Carolina and Vivatto substrates demonstrated favorable results for the variables analyzed in the absence of addition of liquid peat. However, when liquid peat was incorporated, the Vivatto substrate showed superiority in relation to the Carolina substrate. For cv. Cinderella, it was observed that the Carolina substrate demonstrated superiority in relation to most of the variables analyzed in the absence of addition of liquid peat. However, root size in cv. Cinderella was significantly larger when grown in the Vivatto substrate. When liquid peat is added to the production of lettuce seedlings of the Grand Rapids and Cinderela cultivars, the dose of 1% proves to be the most effective in terms of the results obtained for the variables analyzed, regardless of the substrate used. [ABSTRACT FROM AUTHOR]

ABSTRACT In disease assessment, the use of diagrammatic scales provides a standard reference point for comparison. There is still no precise and accurate scale for the evaluation of sporulation intensity of downy mildew in lettuce seedlings. The objective of this study was to propose a diagrammatic scale for the evaluation of downy mildew severity in lettuce seedlings. Thirty lettuce seedlings with different sporulation intensities were used to develop the proposed diagrammatic scale. Solaris lettuce cultivar was sown, and fifteen days after sowing, inoculations occurred using distilled water, the pathogen sporangia, and Tween 20. The monitoring of disease development was performed daily.When the first sporulation appeared on the cotyledonaryleaves,the proposed scale was verified to meet the minimum and maximum levels of disease severity. Two evaluators verified the accuracy, precision and performed the estimation of the sporulation and reproducibility using a scale. The images obtained are important in the standardization of a scale to identify resistant, tolerant and susceptible plants to downy mildew. Furthermore, it allows validating a diagrammatic scale of sporulation intensity of B. lactucae in lettuce seedlings. Thus, it is the diagrammatic scale developed in the work will guide future research to accelerate the detection of mildew severity in lettuce seedlings.

Abstract The objective of this work was to evaluate the occurrence of the maternal effect on thermotolerance in lettuce (Lactuca sativa) seeds, as well as to find an enzymatic marker for this trait in lettuce seedlings. Seeds from the Everglades thermotolerant cultivar, the Verônica susceptible cultivar, and their reciprocal hybrids were used. For each cultivar and reciprocal hybrid, germination percentage and vigor (germination speed index) tests were carried out at 20 and 32°C. Thermotolerance was defined as the capacity to germinate at 32°C. To obtain markers that could be associated with thermotolerance, enzymatic tests were performed. The bands of the electrophoretic enzymatic extracts were quantified using the ImageJ software. The hybrids behaved similarly to their female genitors. When cultivar Verônica was the female genitor, hybrid seeds did not germinate at high temperatures and showed a lower expression of the esterase enzyme. However, when the female genitor was the Everglades cultivar, hybrids showed a high germination at high temperatures and a greater esterase expression. Therefore, there is a maternal effect on tolerance to thermoinhibition in lettuce seeds, and the esterase enzyme can be used as a selective marker to identify homozygous progenies for this trait.

Lettuce (Lactuca sativa) is the most consumed leafy vegetable in Brazil. Usually, sandy soils with low availability of phosphorus are some of the most important factors that limit crop production in Brazil. Therefore, the objective of this work was to evaluate the efficiency of the use of phosphate solubilizing microorganisms in association with phosphate fertilization in the lettuce crop. The experiment was carried out in the experimental field of UNIVAG - Centro Universitário de Várzea Grande, from March to June 2023. An experimental design in randomized blocks was used, with four treatments (without phosphate fertilization and without inoculation; only phosphate fertilization; 50% of phosphorus fertilization and with inoculation; only inoculation) and six replications, totaling 24 plots. The inoculant used was Biomaphos, applied in the sowing furrow at a dose of 0.5 ml per plant. Total and marketable green mass of shoots (g/plant), number of leaves and leaf phosphorus content (g/kg DM) were evaluated. The treatment where only inoculation with Biomaphos was used provided lower total green mass of the aerial part. On the other hand, the commercial green mass was superior in the treatment where only the phosphorus fertilizer was used. For the variable number of leaves, there was no significant effect of the treatments. Phosphorus leaf content was higher in the treatment where only phosphorus fertilization was used, the other treatments did not differ from each other. The inoculation of phosphate solubilizing bacteria did not contribute to increase the availability of P for the lettuce crop. [ABSTRACT FROM AUTHOR]

Widely used in large-scale grain-producing species production systems, no-tillage has been adopted for vegetable production. However, the high number of possibilities of combinations between cover plants and successors demands constant studies on the theme. Current research evaluates the use of different species of grasses and legumes as possible cultures predecessors to no-tillage for lettuce. Six treatments were evaluated with cover plants: crotalaria (Crotalaria juncea), guandu beans (Cajanus cajan), feijão-do-porco bean (Canavalia ensiformis), millet (Pennisetum glaucum) and sorghum (Sorghum bicolor), plus spontaneous vegetation as control. There was a positive effect of lettuce cultivation in succession to sorghum, millet and feijão-do-porco bean, whilst cultivation in succession to crotalaria and guandu beans showed decrease in fresh mass, number of leaves, top diameter and productivity. Results show that the formation of abundant biomass on the soil, provided by the grass species P. glaucum and S. bicolor, improves the conditions of lettuce cultivation in a no-tillage system if the crop´s correct nutritional and water management is carried out. Further, C. ensiformis provides the best development of lettuce, while the cultivation of C. juncea should be avoided due to rates in the culture´s losses. [ABSTRACT FROM AUTHOR]

El hierro (Fe), es un oligoelemento indispensable para la salud humana y su deficiencia afecta a 1200 millones de personas en el mundo. La biofortificación agronómica puede mitigar esta deficiencia ya que su aplicación en los cultivos mejora la biosíntesis de compuestos bioactivos y propicia su bioacumulación. El objetivo del presente trabajo fue evaluar el efecto de la aplicación foliar de Fe (FeSO4) sobre el rendimiento, biosíntesis de compuestos bioactivos y acumulación en lechuga. Para ello cinco tratamientos fueron aplicados vía foliar: 0, 10, 20, 30 y 35 µM L-1. En la cosecha, se cuantificó la calidad nutracéutica y la acumulación de Fe en hojas, así como la productividad de la planta de lechuga. La biofortificación con Fe modificó positivamente la biosíntesis de compuestos fitoquímicos y su concentración en hojas de lechuga, sin afectar el rendimiento. La aspersión foliar de Fe es una alternativa para incrementar la biosíntesis de compuestos fitoquímicos e incrementar la concentración de este elemento en lechuga.

El uso prolongado de fertilizantes químicos sintéticos produce efectos negativos en la fertilidad del suelo. Como alternativa, en los últimos años se ha propuesto la utilización de microorganismos en la agricultura. El objetivo de este ensayo fue evaluar la eficiencia agronómica de aislados de microorganismos de diferentes suelos con cultivos nativos andinos, en la germinación y el crecimiento de plántulas de tomate y lechuga. Para ello se aislaron y seleccionaron bacterias fijadoras de nitrógeno de vida libre utilizando medio Ashby en suelos y rizosfera de cultivos de amaranto (Amaranthus quitensis Kunth), mora (Rubus glaucus Bentham), zanahoria blanca (Arracacia xanthorriza Bancr.) y mashua (Tropaeolum tuberosum Ruiz & Pav.). Posteriormente se realizaron pruebas fisiológicas y bioquímicas para seleccionar las bacterias que se asemejaban al género Azotobacter sp., y se inocularon en cultivos en invernadero de lechuga y tomate, de febrero a abril de 2018, donde se midieron los días a la germinación, altura de la planta, número de hojas, y se realizó un análisis de varianza y test de Tukey para evaluar si existían diferencias estadísticas entre los tratamientos. En la inoculación de 3 cepas en el cultivo del tomate se observó un adelanto significativo en el tiempo de germinación de 3-4 días. En 9 de los tratamientos se constató un aumento significativo en la altura de la planta tanto de tomate como de lechuga y el número de hojas aumentó significativamente en 6 tratamientos de lechuga y 3 de tomate. La cepa bacteriana que mejores resultados obtuvo fue aislada en la rizosfera del cultivo de mora.

A alface tem o nitrogênio como nutriente limitante para seu crescimento e desenvolvimento, o manejo adequado desse elemento resulta no aumento da produtividade, maior massa e maior teor de macro nutrientes e clorofila nas folhas. Este trabalho teve como objetivo avaliar o efeito de diferentes doses de nitrogênio sobre a concentração de nutrientes nas folhas de quatro cultivares de alface. O experimento foi conduzido em casa de vegetação, as cultivares usadas foram: roxa, lisa, crespa e mimosa. O delineamento foi casualizado com cinco repetições, sendo cinco doses de nitrogênio: 0, 50, 100, 150 e 250 kg ha-1, aplicadas em forma de ureia. Antes da colheita foi avaliado o teor relativo de clorofila e depois da colheita a massa fresca, massa seca e teor de nutrientes. O nitrogênio teve interação com todos os parâmetros avaliados, sendo que a cultivar mimosa foi a mais responsiva e apresentou aumento no teor de nitrogênio com o aumento das doses aplicadas.

Resumo: O trabalho teve como objetivo avaliar a resposta da cultura da alface em função de diferentes saturações por bases. O experimento foi conduzido em vaso, na casa de sombra no Instituto Federal de Educação Ciência e Tecnologia IFMT-Campus Confresa. O delineamento experimental utilizado foi o inteiramente casualizado com cinco doses de calcário de PRNT 150% (0; 1,12; 2,75; 4,38 e 6,01 gramas por vaso), visando atingir as seguintes saturações por bases: 30, 50, 70 e 90% e a testemunha com 16% já encontrado no solo, com quatro repetições. Aos 30 dias após o transplantio realizou-se as avaliações de altura de parte aérea, fitomassa fresca de parte aérea, índice SPAD, comprimento de raiz e fitomassa fresca de raiz. Não houve influência nas variáveis de índice SPAD, comprimento de raiz e fitomassa fresca de raiz em uma variação do V% de 16 a 90%. As variáveis que apresentaram diferenças significativas foram altura de parte aérea e fitomassa fresca, critérios mais importantes para a comercialização da hortaliça, tendo melhores resultados em 62,41 e 80% respectivamente.

Objetivou-se nesta pesquisa avaliar os efeitos de níveis de drilocomposto e da adubação com NPK no crescimento e produção de alface. O experimento foi realizado em casa de vegetação, no delineamento inteiramente casualizado em esquema fatorial 6 x 2, com 4 repetições, considerando seis níveis de drilocomposto (0; 25; 50; 75; 100 e 125 g/planta) e ausência e presença de adubação com NPK. As variáveis analisadas foram: número de folhas total e comercial, a massa da parte aérea fresca comercial e total, além das massas da parte aérea total e comercial, da raiz e total secas. Verificou-se interação dupla entre o drilocomposto e a adubação com NPK para as variáveis avaliadas, exceto para a massa seca de raiz que teve efeito isolado dos níveis do adubo orgânico utilizado. A adubação com NPK aumentou o crescimento e produção de alface quando não teve aplicação do drilocomposto. Da mesma forma, que os níveis deste adubo aumentou o crescimento e produção de alface somente na ausência de NPK.

Lettuce (Lactuca sativa) belongs to the asteraceae family, known worldwide and appreciated for generations. Due to the great acceptance, the lettuce is a vegetable of high consumption. In search of solutions for high productivity some techniques have been researched to reduce the stress suffered by the plant to the environment. This study aimed to verify that the aqueous extract of tiririca, in different strengths, present some allelopathic effect on the development of the lettuce. The use of the aqueous extract, which has in its composition the Indole Acetic Acid-AIA (Auxin), was used by capillary irrigation, with the following treatments: T0-control; T1- 25% of concentration; T2- 50% of concentration; T3- 100% of concentration. This study consisted of five replicates and five plants per treatment, with a total of 100 plants. The design was completely randomized. The analyzes were root size, shoot development by fresh mass plant, number of leaves and chlorophyll content. According to the data, it was observed that the concentration of the 100% root extract resulted in higher values of root development, however, affected shoot growth, a result verified in the fresh mass, in which the plants presented reduced weight when compared to the other treatments, and consequently affected the amount of leaves produced by the plants submitted to this treatment, the chlorophyll content was also lower for the plants treated with the maximum concentration of the extract. Therefore, it can be concluded that high dosages of the tiririca extract had an allelopathic effect inhibiting the growth and development of the lettuce plants, and did not present a satisfactory result.

O consumo per capita de café no Brasil é estimado em 4,9 kg de café torrado e moído o que remete a uma elevada geração de borra de café residual. O processo de decomposição promove dentre outros, a formação de líquidos. Esse estudo objetivou avaliar o impacto ambiental, ecotoxicológico do extrato solubilizado da borra de café em de sementes de alface. Foi utilizado o delineamento inteiramente casualizado com sete tratamentos com três repetições. Foram colocadas 10 sementes de alface em placa de Petri com substrato papel de filtro e umedeceu-se com 4,0 mL.. Houve um efeito negativo do extrato BCR sobre a taxa de germinação porém não foi possível determinar a dose CL50 com os tratamentos testados. Observou-se efeito subletal a partir do crescimento radicular de alface com o aumento das doses. A CEO foi estabelecida no tratamento com 0,1 mL. Com isso, evidencia-se que a espécie estudada possui baixa tolerância ao poluente e que o mesmo se apresenta como uma substância potencialmente poluidora.

O presente estudo teve como objetivo avaliar a tratabilidade e a toxicidade de efluente têxtil submetido ao processo Foto-Fenton heterogêneo utilizando sementes de alface (Lactuca sativa) como organismos-teste. As amostras de efluentes foram coletadas na ETE de uma indústria têxtil e submetidas ao tratamento oxidativo, que teve duração de 105 minutos. Em intervalos de tempo (15, 30, 45, 60, 75, 90 e 105 minutos), alíquotas foram retiradas para análises da toxicidade e para análises físico-químicas (cor, compostos aromáticos, turbidez, nível de pH e peróxido residual). As respostas da toxicidade foram avaliadas a partir dos resultados do percentual de germinação e da inibição de crescimento da radícula e do hipocótilo da planta. A taxa média de germinação absoluta após o tratamento foi de 72,5%. Uma inibição de 30,6% do hipocótilo e de 99% da radícula foi observada. Em relação aos parâmetros físico-químicos, o processo foto-Fenton heterogêneo foi efetivo, apresentando uma remoção de cor de 90%, dos compostos aromáticos de 80 % e da turbidez de 30%.

Abstract This study aimed to investigate the occurrence of parasitic structures in curly lettuce (Lactuca sativa L.) sold in food stalls open markets in Cuiabá city, in the Brazilian state of Mato Grosso (MT). For this purpose, 50 samples were evaluated using spontaneous sedimentation and centrifugal flotation methods. These techniques showed positivity in 96% (48/50) and 78% (39/50) of the samples, respectively. The sedimentation method was statistically (p ≤ 0.05) more effective in detecting parasitic structures of the pathogens as Entamoeba histolytica, Ascaris spp., Strongyloides spp., Larvae and Hookworm eggs, when comparing both methods. However, these methods did not differ significantly for the detection of Giardia lamblia. Ascaris spp and Entamoeba coli occurred in 64% (32/50) and 46% (23/50) of the positive samples, respectively, with the highest percentages observed. The occurrence of Blastocystis spp., Fasciola spp., Dipylidium caninum and Ascaris lumbricoides revealed detection exclusively by the spontaneous sedimentation method, while Iodamoeba butschlii and Enterobius vermicularis were detected by centrifugal– flotation procedure. These results could reinforce the need to use methods based on sedimentation and the fluctuation of parasite structures in the analysis of lettuce. The presence of parasites in lettuce by fecal origin, with recognized pathogenicity, represents a risk to consumer health and demonstrates a deficit in good agricultural practices in the production, distribution and commercialization of lettuce.

Abstract The objective of this work was to assess the genetic control of tolerance to thermoinhibition in lettuce (Lactuca sativa) seeds. Seeds of the F1, F2, and F2:3 generations derived from the cross between cultivars Everglades (tolerant to thermoinhibition) and Verônica (sensitive to thermoinhibition) were used, besides seeds from the parents. Seed germination tests were conducted in a completely randomized design, with four replicates of each parent, eight of F1, and four of each of the 26 F2:3 progenies. The mean of the F2 population was considered as the mean of the sample of the 26 progenies. The genetic control of thermoinhibition tolerance in lettuce seeds is attributed to one or a few genes. The additive effects are more expressive than the nonadditive ones, and narrow-sense heritability is relatively high, allowing the prediction of success in selection.

Abstract: The objective of this work was to evaluate the effect of a microbial fertilizer, produced from phosphate and potassic rocks and earthworm compost, as an alternative to conventional fertilizers, on lettuce (Lactuca sativa) nutrients and soil attributes. The experiment was conducted in consecutive cycles (30 and 60 days) in a soil from the Lorca region, in the municipality of Murcia, Spain. The fertilization treatments were: conventional fertilizer, 100% of the recommended rate (RR); microbial fertilizer, 50% of the RR (5 Mg ha-1); microbial fertilizer, 100% of the RR (10 Mg ha-1); microbial fertilizer, 150% of the RR (15 Mg ha-1); and control, without N-P2O5-K2O fertilization. The microbial fertilizers applied at 100 and 150% of the RR showed significant and positive effects, as well as the best results for plant characteristics. The microbial fertilizer increased total N and available P and K compared with the conventional fertilizer. A residual effect was observed in the successive cycle. The effectiveness of the microbial fertilizer shows it is a viable alternative to conventional fertilizers, with positive effects on plant productivity and soil attributes.

Abstract: The objective of this work was to determine the genetic parameters and the efficiency of different selection indices for biofortified red leaf lettuce (Lactuca sativa var. crispa) lines with agronomic and nutritional potential. The experiment was carried out in a randomized complete block design with three replicates and 31 crisp-textured and red-tinted leaf lettuce genotypes: the Belíssima cultivar, with a low carotenoid content and rich in anthocyanins; and 30 lines from the cross between the Belíssima and Uberlândia 10000 cultivars, rich in carotenoids and with a low anthocyanin content. The assessed traits were: total green mass (g), stem diameter (cm), leaf count, plant diameter (cm), foliar temperature (°C), soil plant analysis development (SPAD) index, anthocyanin content (mg 100 g-1 sample), and bolting (days after sowing). To estimate selection gains, 12 genotypes were selected through selection indices. The traditional index proposed by Smith & Hazel and the sum of ranks index by Mulamba & Mock provided the highest selection gains in the biofortified lettuce. The coefficient of genotypic determination for leaf count, anthocyanin content, bolting, and SPAD index is of high magnitude.

Diversos fatores ambientais, como altas temperaturas e chuvas intensas, afetam o crescimento e o desenvolvimento da alface. Assim, torna-se necessária a realização de testes de cultivares para verificação da adaptação a diferentes ambientes de cultivo. Este trabalho teve por objetivo a avaliação do desempenho de cultivares de alface crespa roxa em campo aberto, durante as estações seca e chuvosa, na Amazônia Central. O delineamento experimental adotado foi o de blocos casualizados, com quatro repetições, sendo os tratamentos constituídos por onze cultivares: Banchu Red Fire, Belíssima, Lavine, Mirella, Pira Roxa, Red Star, Rosabela, Rubia, Rubinela, Scarlet e Vermelha Rouge. Concluiu-se que, durante a estação chuvosa, o desenvolvimento das plantas foi severamente prejudicado, devido à incidência de Rhizoctonia solani. As cultivares Banchu Red Fire, Rosabela e Scarlet apresentaram os melhores parâmetros de crescimento e desempenho agronômico, durante a estação seca, mostrando capacidade de adaptação na região e podendo ser indicadas para o cultivo em condições climáticas similares às da Amazônia Central.

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Resumo Objetivou-se avaliar a adaptação de cultivares de alface com base na metodologia dos graus-dia, em estufa, no vale do Gurguéia. O experimento foi conduzido em ambiente protegido, na Universidade Federal do Piauí - UFPI/CPCE. O delineamento adotado foi em blocos ao acaso, sendo os tratamentos cultivares de alface. As cultivares utilizadas foram: Simpson, Bruna, Palmas e Grand Rapids - TBR. Os dados meteorológicos (temperatura do ar, umidade relativa, pressão atmosférica, velocidade dos ventos e precipitação) foram obtidos em uma estação meteorológica portátil que foi instalada no ambiente protegido. A temperatura do ar durante o experimento apresentou máxima de 33 °C e mínima de 26 °C. As cultivares ‘Simpson’ e ‘Grand Rapids’ apresentaram um ciclo mais precoce (45 dias), quando comparada às demais (52 dias), ambas com constante térmica (CT) de 898 °gd. As cultivares ‘Bruna’ e ‘Palmas’ apresentaram CT = 1050 °gd. Dentre as cultivares avaliadas, as cultivares ‘Palmas’ e ‘Bruna’ obtiveram comportamento e morfologia adequados em relação às altas temperaturas regionais. Dessa forma, conclui-se que as cultivares ‘Palmas’ e ‘Bruna’ possuem potencial produtivo para a região, quando cultivada em ambiente protegido.

Lettuce is commonly consumed in Brazil. It is mainly eaten in natura, and this is the reason why it is a vehicle of parasitic contamination. The objective of this work was to evaluate the parasitic contamination of three different organic fertilizers -filter cake (TF), manipueira (MA), and agricultural byproduct (RA) -, in Lactuca sativa cv. Valentina samples,using the following applications: TF/T1: no fertilizer, TF/T2: 3.6kg/m², and TF/T3: 7.2kg/m²; MA/T1: no fertilizer, MA/T2: 4.32L/m², and MA/T3: 8.64L/m²; and RA/T1: no fertilizer, RA /T2: 3.6 kg / m², and RA/T3: 7.2 kg/m². The leaves and capsules used in the research were washed with a 0.5% neutral detergent solution and these samples were subjected to Hoffman’s and Faust’s methods. The results of the analyses demonstrated that 100% of the samples were contaminated with Ancilostomydaelarvaeregardless of the fertilizer or concentration used. Ancilostomydaelarvae were only found with the following specifications: TF/T1 (83.33%), TF/T2 (66.66%), TF/T3 (50%), MA/T1 (66.66%), MA/T2 (83.33%), MA/T3 (33.33%), RA/T1 (80%), RA/T2 (60%), and RA/T3 (40.00%). Ancilostomydaelarvae associated with Ancilostomydaeeggs were found with TF/T1 (0%), TF/T2 (16.66%), TF/T3 (0%), MA/T1 (16.66%), MA/T2 (0%), MA/T3 (0%), RA/T1 (0%), RA/T2 (0%), and RA/T3 (0%). And Ancilostomydaelarvae associated with Taeniaeggs were found with TF/T1 (16.66%) TF/T2 (16.66%), TF/T3 (50%), MA/T1 (16.66%), MA/T2 (16.66%), MA/T3 (66.66%), RA/T1 (20%), RA/T2 (40%), and RA/T3 (60%). Considering the research results, we reinforce the need for sanitizing and controlling the means of contamination in vegetables grown for sale and consumed in naturato prevent parasitic infection in consumers.

Entre as hortaliças brasileiras mais cultivadas e consumidas se destacam as alfaces de folhas crespas, cultivadas durante todo o ano em todas as regiões do país. No presente trabalho avaliou-se a produção comercial de alface crespa solta, cultivar Isabela®, em função da aplicação foliar de fertilizantes líquidos. A fase experimental foi realizada na área experimental do curso de Engenharia Agronômica da Universidade Paranaense - UNIPAR, localizado no município de Umuarama-PR. Os tratamentos foram dispostos no delineamento de blocos ao acaso em esquema fatorial 3 x 4, constituído por três fertilizantes líquidos (Spin®, Fence®, e associação entre Spin® + Fence®) e quatro doses (0; 1; 2 e 3 L ha–1), com quatro repetições. A colheita foi realizada 47 dias após o transplantio das mudas de alface. Analisou-se a massa fresca e a massa seca de folhas, a massa fresca e o comprimento das raízes por planta e os resultados evidenciaram resposta polinomial quadrática para todos os fatores. O uso exclusivo dos fertilizantes líquidos via aplicação foliar foi superior à testemunha para todas as variáveis avaliadas da alface solta crespa, cv. Isabela®, que responde significativamente (p≤0.01) entre as doses de 1 a 1,67 L ha–1, primando associação entre Spin® + Fence® sobre Spin® e Fence®.

Objetivou-se com este trabalho avaliar a fitotoxicidade de elutriato obtido a partir do lodo de ETA e ETE antes e após o tratamento por vermicompostagem (TVC). Os ensaios utilizaram a água interfacial de lodos puros e consorciados nas parcelas de 75, 50 e 25% dos respectivos lodos (mistura dos lodos de ETA e ETE). Para a avaliação da toxicidade foram utilizadas sementes de alface, Lactuca sativa. As sementes foram colocadas em placas de Petri com papel de filtro e umedecidas com 4 mL de solução de elutriato; as placas foram vedadas com papel de filme plástico, para evitar a evaporação do elutriato, e posteriormente com papel alumínio, para preservar a ausência de luz, sendo mantidas numa incubadora, do tipo DBO5 a 25±1 ºC por 120 h. O delineamento foi inteiramente casualizado, com 15 amostras de cada mistura de lodo antes e 15 após o Tratamento por Vermicompostagem (TVC), 5 diluições (10, 25, 50, 75 e 100%) e três repetições, totalizando 450 parcelas de amostras e 6 parcelas de controles. Em todas as amostras e nos controles foram determinadas as concentrações de Al. O teste de toxicidade mostrou que houve um aumento no índice de germinação após TVC; assim como o elutriato com a maior diluição de 10% e menor concentração de Al, obtiveram-se resultados mais expressivos, mostrando que a germinação das sementes foi reduzida proporcionalmente ao aumento nas concentrações de Al presente no elutriato.

O objetivo deste trabalho foi realizar análise econômica do uso de ambientes protegidos e diferentes volumes de recipientes no cultivo de alface em sistema de produção orgânica. Os experimentos foram realizados em dois ambientes protegidos: estufa coberta com polietileno e aberta nas laterais e estufa coberta com polietileno fechada nas laterais com tela anti-inseto em ambos, o delineamento experimental foi em blocos casualizados com cinco tratamentos (volumes de recipientes): 70, 160, 250, 340 e 430 cm³. Para avaliar a análise econômica, utilizaram-se a produtividade e os custos para cada m² de cultivo e considerado o preço local para os respectivos produtos e insumos no último trimestre de 2017, considerando 3% de custo de administração, 6% de custo de oportunidade, depreciação da infraestrutura e custos da terra. Houve lucro acima da remuneração mínima (6% a.a.), em todos os tratamentos, exceto aquele com recipiente de 70 cm³ em estufa com tela anti-inseto, em estufa sem tela anti-inseto o recipiente de 250 cm³ foi responsável pelos melhores indicadores econômicos entre todos os tratamentos.

Este trabalho teve objetivo de avaliar o efeito da adição de cama de frango (CF) e esterco bovino (EB) à fibra de coco (FC) na formulação de um substrato para produção de mudas de alface tipo americana. O experimento foi conduzido no município de Mossâmedes-GO, no período de outubro de 2016 a novembro de 2016. O cultivo foi conduzido em estufa coberta de PEBD translúcido. O experimento foi realizado em delineamento inteiramente casualizado, sendo sete tratamentos de substratos (100%FC; 90%FC + 10%EB; 80%FC + 20%EB; 60%FC + 40%EB; 90%FC + 10%CF; 80%FC + 20%CF; 60%FC + 40%CF) e 40 repetições. Foi realizada análise física e química dos sete substratos. Avaliou-se a porcentagem de emergência; a massa do sistema radicular e parte aérea no momento do transplantio. A fibra de coco pura, como substrato, e sem fertirrigação é inviável para a produção de mudas de alface. Os substratos formulados com 80% de fibra de coco + 20% de esterco bovino curtido e 60% de fibra de coco + 40% de esterco bovino curtido são adequados para produção de mudas de Alface. A cama de frango mostrou-se uma fonte muito salina, mesmo curtida, comprometendo a emergência e desenvolvimento das mudas.

Abstract: The objective of this work was to evaluate the adaptability of different lettuce (Lactuca sativa) cultivars grown in no-tillage on straw of ruzi grass (Urochloa ruziziensis), as well as its effects on soil temperature and weed control, in successive cultivations in the summer. The treatments were carried out in a randomized complete block design, with four replicates, in a split-plot arrangement (2x4), in which soil management (no-tillage on ruzi grass and convention tillage) was the main plot, and the different crisphead lettuce cultivars (Amanda, Solaris, Vanda, and Vera), the subplots. No difference was observed between cultivars for soil management. No-tillage reduced the soil temperature by up to 3.7°C and weed density by 3.7 times, in comparison with conventional tillage. Ruzi grass promoted a greater bed conservation. In comparison to with conventional tillage, the no-tillage management of lettuce cultivated on ruzi grass straw resulted in a lower yield in the first crop due to excess straw; in a similar yield in the second crop; and in a greater yield in the third crop. Lettuce cultivated on ruzi grass straw in no-tillage management results in a greater sustainability, in comparison with conventional tillage, in three successive plantings.

The objective was to evaluate the growth variables of lettuce seedlings produced in different alternative substrates, in total substitution to the commercial substrate. The experiment was carried out in a randomized block design with five substrates (T1 = commercial substrate, control, T2 = sand / straw / bovine manure, T3 = Sand / straw), at the State University of Mato Grosso (UNEMAT), Nova Xavantina (T4 = commercial substrate / straw / bovine manure and T5 = Substrate / straw / humus) x two varieties of lettuce (Americana delícia and Regal of summer "lisa") totaling ten treatments with four replications. The commercial substrate provided higher growth of lettuce seedlings independent of the cultivar used. Alternatively, the use of the commercial substrate / straw / bovine manure for its low cost and easy availability can also be used, although its performance is inferior to the commercial substrate

Abstract: The objective of this work was to estimate the stability and genotypic adaptability of advanced lines and cultivars of curled green-leaf lettuce (Lactuca sativa), in different growing environments and seasons, using the REML/Blup mixed model. Ten genotypes, seven cropping environments, and two growing seasons were studied in 2015. Plant yield traits were evaluated, and data were subjected to the Selegen-REML/Blup software. Genotype stability and adaptability were analyzed using the harmonic mean of genotypic values (HMGV) and the relative performance of genotypic values (RPGV), respectively. The harmonic mean of RPGV (HMRPGV) was used to simultaneously estimate the stability, adaptability, and yield of breeding lines or cultivars. Considering the combined analysis of the two seasons for the set of traits, the lines L6, L7, and L8 were selected as promising ones and recommended for planting. The breeding lines selected for all season exhibit good yield and are considered superior to the commercial cultivars Vanda and Vera.

Copyright of Revista de Ciências Agrárias is the property of Sociedade de Ciencias Agrarias de Portugal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Verde de Agroecologia e Desenvolvimento Sustentável is the property of Revista Verde de Agroecologia e Desenvolvimento Sustentavel and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Cientifica is the property of Fundacao de Apoio a Pesquisa e Extensao and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The objective was to evaluate the effects of levels of compost and fertilization with NPK on growth and production of lettuce. The experiment was carried out in a greenhouse, in a completely randomized design in a 6 x 2 factorial scheme, with four replications, considering six levels of compost (0; 25; 50; 75; 100 and 125 g plant-1) and absence and presence fertilization with NPK. The evaluated parameters were number of total and commercial leaves, mass of fresh commercial and total aerial part, mass of commercial and total dry aerial part, dry root mass and total dry mass. There was an interaction between the drilocomposite and NPK fertilization for the evaluated parameters, except for root dry matter. The fertilization with NPK increased the growth and production of lettuce when there was no application of the compost. Likewise, that the levels of this fertilizer increased the growth and production of lettuce only in the absence of NPK. The application of drilocomposite increases the growth of lettuce plants and can replace fertilization with NPK. [ABSTRACT FROM AUTHOR]

The objective of this work was to evaluate the lettuce yield under the different management of nitrogen fertilization. The ammonium sulfate (NH4)2 SO4 with 950 kg ha-1 was used as a source of nitrogen. The treatments were constituted: 100% of the N incorporated in the base; 100% of N in single application coverage; 50% of the N incorporated in the base and 50% in cover parceled in 2 times; 25% of the N incorporated in the base and 75% in coverage, divided in 3 times; 100% of N in 3-fold parcel coverage and the control (without N application). The plants were harvested 42 days after transplanting and analyzed the variables weight of the fresh aerial part, aerial dry mass, the number of leaves and height of plant and stem diameter. It was verified that, for all evaluated characteristics, the response to nitrogen application was positive. It was concluded that the treatments 2, 3, 4 and 5 did not difference significantly from each other, and there was no decrease in productivity, the control verified the nitrogen requirement for this crop being below the averages in all variables analyzed.

A presença de contaminantes emergentes em águas de superfície foi detectada em estudos realizados por pesquisadores de vários países. Neste estudo foram monitorados parâmetros fisiológicos de substratos contaminados pelos antibacterianos, nitrofurantoína (NTF), cloridrato de tetraciclina (CTC), cefalexina (CEF), amoxicilina (AMX), azitromicina (AZI) e norfloxacina (NOR) e pelos analgésicos, diclofenaco de sódio (DFS), dipirona monoidratada (DMH) e diclofenaco de potássio (DFP), em culturas de Lactuca spp. (alface) e de Saccharomyces cereviseae in vitro. Todas as substâncias avaliadas causam alterações metabólicas e fisiológicas na cultura de Lactuca spp., alterando a taxa de germinação, o comprimento de folhas, o comprimento de raízes e as taxas de clorofila alfa e de clorofila beta. No entanto apenas NOR, DFS e DMH causam alterações na concentração inibitória para a produção de espuma de S.cereviseae em concentrações ≤ 5000 ppm.

This study aimed to determine the toxicity of Cu, Cd, Ni, Pb and Zn in two Colombian agricultural soils, Andisol and Vertisol, by bioassays with Lactuca Sativa and Vibrio fischeri. The metals were individually added to soils exceeding the intervention level of Andalusia. Subsequently, they were incubated at 25 °C and 60% humidity for 60 and 90 days, respectively. The experimental design was completely randomized with three replicates. After each incubation, the concentration of the metals in aqueous extracts was determined, and bioassays were carried out with Lactuca Sativa and Vibrio fischeri. Statistical analysis of results, post hoc comparisons (Tukey), correlations and principal component analysis were performed to find the factors that affected the organisms under study. It was found that Vertisol showed a higher immobilization capacity of all metals, based on their clay content and neutral pH, which was reflected in less toxicity on the organisms tested, indicating that this soil acted as a protection against mobility of pollutants in soil solution. The V. fischeri test presented greater sensitivity to contaminants, allowing a better discrimination of toxicity levels. The ability of both soils to inhibit toxicity increased over time, possibly through the interaction of metals with the different soil components, and the decrease in their mobility by mechanisms such as the formation of stable complexes, and was related to the increase of pH.

Uma das razões para obter sucesso na horticultura é a produção de mudas de qualidade, utilizando substratos em substituição do solo na formação de mudas. Desse modo, objetivou-se com este trabalho avaliar o desempenho de mudas de alface e rúcula utilizando substratos produzidos com vermicompostos juntamente com a serragem e casca de arroz como agentes condicionantes. Foram realizados dois experimentos em Vilhena, Rondônia, utilizando o delineamento experimental inteiramente casualizado, em esquema fatorial 3x2 com sete repetições, correspondendo a três substratos e duas cultivares, tanto para alface quanto para rúcula. A proporção dos materiais foi de 1:3 do volume total de solo, de esterco de aves e agente condicionante, sendo utilizada a minhoca Vermelha Californiana (Eisenia foetida). Para as cultivares, tanto de alface quanto de rúcula, foram avaliadas a altura de plântulas, diâmetro do colo, massa seca da parte aérea, das raízes e total. Não foi observada diferença significativa entre os tratamentos avaliados em relação a massa seca das raízes de alface da cultivar Crespa, porém para a cultivar Americana, os tratamentos utilizando vermicomposto com agente condicionante a serragem ou casca de arroz, foram superiores ao substrato comercial em relação a massa seca das raízes. Entre as cultivares de rúcula, não foi observado diferença significativa entre os tratamentos sobre as variáveis avaliadas. Portanto, é possível concluir que os substratos produzidos a partir de vermicompostos com serragem e casca de arroz como agentes condicionantes, podem substituir o substrato comercial durante a produção de mudas de alface e rúcula.

A alface é uma hortaliça muito consumida no Brasil em sua forma in natura, tornando-se um veículo de transmissão parasitária. Este trabalho teve como objetivo avaliar a contaminação parasitária em três diferentes fertilizantes orgânicos sendo torta de filtro (TF), manipueira (MA) e resíduos agroindústrias (RA) em amostras de Lactuca sativa cv. Valentina utilizando as seguintes dosagens: TF/T1: Sem adubação, TF/ T2: 3,6 Kg/m2 e TF/T3: 7,2 Kg/m2. MA/T1: Sem fertilizante, MA/T2: 4,32L/m2 e MA/T3: 8,64L/m2 e RA/T1: Sem adubação, RA/T2: 3,6 Kg/m2 e RA/T3: 7,2 Kg/m2. As amostras foram submetidas aos métodos de Hoffman e Faust a partir do lavado das folhas e caules com uma solução de detergente neutro a 0,5%. O resultado das análises demonstrou que 100% das amostras estavam contaminadas com larvas de ancilostomídeo independentemente do fertilizante e concentração utilizada. Foram encontrados somente larvas de ancilostomídeo (LAC) em TF/T1(83,33%),TF/T2(66,66%) ,TF/T3(50%), MA/T1 (66,66%), MA/T2(83,33%), MA/T3(33,33%), RA/T1 (80%), RA/T2(60%) e RA/T3(40,00%), LAC associados a ovos de ancilostomídeo TF/T1(0,00%), TF/T2(16,66%), TF/T3(0%), MA/T1 (16,66%), MA/T2(0%), MA/T3(0%), RA/T1 (0%), RA/T2(0%) e RA/T3(0%) e LAC associados a ovos de Taenia sp.: TF/T1(16,66%) TF/T2(16,66%), TF/T3(50%), MA/T1 (16,66), MA/T2(16,66%), MA/T3(66,66%), RA/T1 (20%), RA/T2(40%) e RA/T3(60%). Conclui-se a partir dos resultados, é necessária a higienização e controle dos meios de contaminação de hortaliças cultivadas com destinação a venda e consumida in natura para prevenir a infecção parasitária dos consumidores.

Introdução: A contaminação de alimentos consumidos crus, como salada de alface, é previsível pela origem telúrica e pela manipulação indevida nos estabelecimentos comerciais constituindo um possível risco à saúde pública. A utilização de fermentado acético como antibacteriano poderia ser um mecanismo hábil para melhorar a qualidade e a segurança desse alimento. Objetivo: Avaliar a qualidade microbiológica das saladas de alface (Lactuca sativa) comercializadas na cidade de Duque de Caxias, RJ, e a efetividade do fermentado acético de maçã como descontaminante. Método: Foram coletadas amostras de saladas de alface em quatro restaurantes, que foram analisadas antes e após a descontaminação com fermentados acéticos em acidezes voláteis (4, 5 e 6 em g. 100 mL-1) e concentrações de 10% e 50% quanto à contagem de bactérias aeróbicas mesófilas, coliformes totais e termotolerantes e quanto à presença de Salmonella spp. Resultados: As análises revelaram má qualidade das amostras em três restaurantes (A, B, C) nos quais, embora não tenha sido constatada a presença de Salmonella spp., verificou-se contagens elevadas de bactérias aeróbias mesófilas e de coliformes totais e termotolerantes. De acordo com as normas legais, em dois estabelecimentos as amostras seriam reprovadas pelo excesso de coliformes termotolerantes. Com o uso do fermentado acético na descontaminação, houve redução das contagens bacterianas, permitindo que todas as amostras apresentassem condições satisfatórias para consumo humano. Não houve diferença significativa (p < 0,05) entre os tratamentos com diferentes concentrações e acidezes de fermentado acético em relação as amostras não tratadas. Conclusões: O fermentado acético pode ser uma alternativa segura e prática para melhorar a qualidade higiênico-sanitária da alface em saladas cruas, garantir a segurança alimentar e reduzir os riscos à saúde humana.

ABSTRACT: The phenological stage, post-harvest processing and quantity of material can interfere in the allelopathic activity of extracts. The objective of this study is to test the allelopathic effect of aqueous extracts of the leaves of Annoni grass (Eragrostis plana), an invader of natural pastures. Twelve extracts were prepared by combining the phenological stage of the plants when harvesting the leaves (vegetative; flowering), post-harvest processing before extraction (fresh; dry at 40 oC), and the amount of plant material (5, 15, and 25 g 100 mL-1 distilled water). Two bioassays were conducted in a germination chamber, with evaluation of germination and growth of seedlings of lettuce (Lactuca sativa) and white clover (Trifolium repens). The extracts with higher allelopathic activity were further developed with 15 and 25 g of dried leaves and harvested in plants at the vegetative stage. Germination was attributed to being the greatest contribution to the divergence between the extracts. White clover was more sensitive to extracts, for which 50% to 67% of the extracts were effectively allelopathic (≥50% inhibition); in lettuce, between 8% and 58% of the extracts exhibited this potential. The phenological stage was the factor with a greater individual effect on the allelopathic activity on lettuce and white clover seedlings, and on lettuce germination. The post-harvest processing responded by the greater variation on germination and germination speed index of white clover. The sensitivity of the white clover to extracts of Annoni grass suggests a compromise of its establishment in pastures with the presence of the invader.

Weeds is one of the main factors in production decrease in several crops and its control represents a high production cost. In the present essay, different mulch were used: banana leaf, grass trimming, maize straw, sawdust, to verify the weed suppression power during the critical period of interference in lettuce. After transplanting the lettuce seedlings, the mulches were placed and the weeds were identified and counted. It were determined relative frequency, relative density, relative abundance and importance value index of each species and fror the different treats 12 and 24 days after transplantation. Cyperus rotunds, Amaranthuys spp., Eleusine indica, Digitaria insularis and Commelina bengalensis were observed. Plant cover provided a reduction in relative density, relative abundance, and weed importance value index, and cover with banana leaf, grass pruning, and maize straw obtained the best results, with lower values for weed quantity and highest values for head diameter, and number of lettuce leaves [ABSTRACT FROM AUTHOR]

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Copyright of Nativa is the property of Revista Nativa and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The effect of different types and concentrations of nutritional broths in the agronomic attributes of the lettuce is evaluated. The experiment was conducted in vegetable beds on a farm in the municipality of Ronda Alta RS Brazil, between August and October 2016. Experimental design consisted of randomized blocks, with seven treatments and five replications. Treatments comprised Bordeaux broth at 0.1 and 0.5%; liquid humus at 2.5% and 5%; Microgeo® at 0.5% and 1.0%; control. Variables analyzed were height of aerial segment, length of the root system, perimeter of the aerial segment, dry matter of the aerial segment and of the root segment, and weight decrease. Bordeaux broth at 0.5% for the variable height of aerial segment provided a greater rate than in the treatment with Microgeo® at 0.5%. For root length, treatment with liquid humus at 5% was equivalent to humus treatment at 2.5%, the former was superior to the others. In the case of dry matter of the root system, the employment of liquid humus and Microgeo®, in the two concentrations, provided the best results. In the case of weight decrease, broth with liquid humus and Bordeaux broth at 0.5% provided the best result. Results indicate the use of nutritional broth for lettuce cultivation. Regard to agronomic attributes, the use of liquid humus (2.5% and 5%) provided the longest roots and the smallest decrease in lettuce weight. [ABSTRACT FROM AUTHOR]

Copyright of Revista Verde de Agroecologia e Desenvolvimento Sustentável is the property of Revista Verde de Agroecologia e Desenvolvimento Sustentavel and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)