ABSTRACT This study aimed to identify the correlations between traits of the groups stem cutting, seedling, stem, and root of cassava. Length, diameter, and weight of stem cutting (Group 1) were measured at each growing season (July, August, September, and October). A total of 300 cuttings were collected after sprouting and planted at seasons of September 22, October 7 and 19, and November 25. Plant height at planting, number of leaves at planting, and number of leaves at 7 days after planting were measured. The number of leaves at transplanting and plant height at transplanting were determined after acclimation (Group 2). Seedling transplanting was carried out on November 9 and 24 and December 3 and 26, and the traits stem (Group 3) and root (Group 4) yield were measured at harvest. Associations between the groups stem cutting and seedling were established by stem cutting diameter and weight, and height and number of leaves at planting. Seedling traits had the greatest influence on the number of buds per stem and stem diameter. Main stem branching height and stem diameter can be used for selecting plants with an indication of the best quality and yield of root traits.

Abstract This study aimed to assess cassava root and stem yield at different spacings and four transplanting seasons of seedlings produced by an adaptation of the rapid multiplication method. The experimental design was a randomized block design with three replications in a factorial (4 × 5) arranged in strips. Treatments consisted of the combinations of growing seasons (November 9 and 24 and December 3 and 26) and spacings (0.6 × 0.6, 0.8 × 0.8, 0.8 × 0.6, 1.0 × 0.6, and 1.0 × 0.8 m). The percentage of survival, main stem branching height, number of branches, base, middle, and upper diameter, mean diameter, stem length, number of buds per stem and hectare, root length and diameter, root fresh matter per plant and hectare, and number of roots per plant were measured at harvest. Seedling transplanting performed up to November 24 favored the expression of stem and root yield. The spacing of 1.0 × 0.6 m was the most suitable for stem yield traits.

RESUMO A lavanda (Lavandula dentata) possui diversas aplicações medicinais, tanto in natura como após processamento industrial. O incremento à produtividade pode ser obtido por meio da propagação massal, ampliando a possibilidade de obtenção de matéria prima para a produção de óleo essencial. O objetivo deste trabalho foi desenvolver um protocolo de micropropagação a partir de explantes obtidos de sementes. Foram avaliados aspectos da germinação, multiplicação, alongamento e enraizamento in vitro e, em seguida, o processo de aclimatização das mudas. A germinação in vitro de lavanda pôde ser obtida apenas com a utilização do meio composto por ágar e água. Para a multiplicação, o uso de meio MS (Murashige & Skoog, 1962) acrescido de 5,0 µM de 6-benzilaminopurina ao meio nutritivo é o mais apropriado. Para o alongamento e enraizamento, a utilização de reguladores de crescimento é dispensável. A aclimatização pode ser obtida diretamente com a transferência do explante para sacos plásticos com substrato, mantidos em casa de vegetação. Foi possível desenvolver um protocolo para o cultivo in vitro (estabelecimento, multiplicação, alongamento, enraizamento e aclimatização) de lavanda a partir de explantes de sementes.

ABSTRACT Lavender (Lavandula dentata) has several medicinal applications, both in the fresh form and after industrial processing. Productivity increase could be obtained through the mass propagation, expanding the possibility of obtaining raw material for production of essential oil. The objective of this work was to develop a micropropagation protocol from explants obtained from seeds. Aspects of in vitro germination, multiplication, elongation and rooting were evaluated and, in sequence, the acclimatization process as well. The in vitro germination of lavender seeds can be obtained using a medium composed of agar and water. For multiplication, the use of MS medium (Murashige & Skoog, 1962) added with 5.0 µM 6-benzylaminopurine to the nutrient medium is the most appropriate. For elongation and rooting, the use of growth regulators is unnecessary. Acclimatization can be obtained directly by transferring the explant to plastic bags with substrate, kept in a greenhouse. It was possible to develop a protocol for the in vitro cultivation (establishment, multiplication, elongation, rooting and acclimatization) of lavender from explants of seed origin.

Abstract In agricultural experiments, measuring all plants that constitute an experimental unit is the most appropriate method for estimating averages. This study analyzed sample sizes (number of plants) for estimating averages of agronomic traits in cassava. The experiment for seedling production was conducted on four sowing dates: September 22, October 7, October 19, and November 25, 2017. The evaluated characters were plant height at planting, number of leaves at planting, number of leaves at 7 days after planting, number of leaves at transplanting, and plant height at transplanting. The seedlings were transplanted to the field on November 9, November 24, December 3, and December 26. Root characteristics and root yield were measured at harvest. The following statistics were measured: minimum, maximum, range, mean, median, variance, standard deviation, and coefficient of variation. The sample size was determined by resampling with replacement when the range of the 95% confidence interval (CI) was 10%, 20%, 30%, and 40% of the average estimate. Larger sample sizes were needed to estimate trait averages with a 95% CI range of 10% of the average estimate, i.e., when estimation accuracy was higher. In contrast, lower sample sizes were required to estimate averages of all characters in all planting times with a 95% CI range of 40%. For measuring seedling production and stem and root yield, 63 and 153 plants are sufficient to estimate averages when the range of the 95% confidence interval was 20%.

Resumen En experimentos agrícolas, medir todas las plantas que constituyen una unidad experimental es el método más apropiado para estimar promedios. Este estudio analizó tamaños de muestra (número de plantas) para estimar promedios de caracteres agronómicos en yuca. El experimento para la producción de plántulas se realizó en cuatro fechas de siembra: 22 de septiembre, 7 de octubre, 19 de octubre y 25 de noviembre de 2017. Los caracteres evaluados fueron la altura de la planta en la siembra, el número de hojas en la siembra, el número de hojas a los 7 días después de la siembra, el número de hojas en el trasplante y la altura de la planta en el trasplante. Las plántulas se trasplantaron al campo el 9 de noviembre, 24 de noviembre, 3 de diciembre y 26 de diciembre. Las características de la raíz y el rendimiento de la raíz se midieron en la cosecha. Se midieron las siguientes estadísticas: mínimo, máximo, rango, media, mediana, varianza, desviación estándar y coeficiente de variación. El tamaño de la muestra se determinó mediante remuestreo con reemplazo cuando el rango del intervalo de confianza (IC) de 95% fue de 10%, 20%, 30% y 40% de la estimación promedio. Se necesitaron tamaños de muestra más grandes para estimar los promedios de rasgos con un rango de IC de 95% de 10% de la estimación promedio; es decir, cuando la precisión de la estimación fue mayor. En contraste, se requirieron tamaños de muestra bajos para estimar promedios de los caracteres en los tiempos de siembra con un rango de IC de 95% de 40%. Para medir la producción de plántulas y rendimiento de tallos y raíces, 63 y 153 plantas son suficientes para estimar promedios cuando el rango del intervalo de confianza de 95% fue de 20%.

ABSTRACT Chia is a plant whose seeds are used in cooking and is a natural source of omega-3 fatty acids, fiber and protein, as well as other important nutritional components such as antioxidants. The objective of this work was to estimate the base temperature, plastochron and chia seed yield for different sowing times in Cruz Alta, Rio Grande do Sul, Brazil. The experimental design was completely randomized and the treatments consisted of different sowing times (September, October and November). For the determination of the base temperature for node emission in the main stem of the plants, the method of least mean square error of linear regression between the number of nodes and the accumulated thermal sum was used. Regarding estimation of the plastochron at each sowing time, a simple linear regression was obtained between the number of nodes in the main stem and the accumulated thermal sum. Seed yield was measured at harvest. Sowing in times with air temperature below 19 ºC should be avoided so that the development of plants is not impaired. Plastochron ranges from 28.01 ºC to 32.26 ºC day for successive node emission in the main stem of chia plants and September sowing promotes higher seed yield.

ABSTRACT. A study was conducted during four growing seasons to investigate the rooting capacity and survival percentage of cassava seedlings from stem cuttings selected based on their number of leaves. The experimental design was a randomized block design with five replications in a factorial scheme (4 × 2 × 2), totalling 16 treatments. Treatments consisted of combinations of growing season (September 22, October 7 and 19, and November 25), stem cuttings smaller (15 to 19.99 mm) and larger (20 to 25 mm) than 20 mm in diameter, and number of leaves on the stem cuttings (3 to 5 and 6 to 8 leaves). The experiment was carried out during the four growing seasons in a Van der Hoeven greenhouse. The greenhouse, as well as the benches on which the treatments were placed, had a north-south orientation. The greenhouse has an automatic mist irrigation system, and the mean temperature was 25 °C. The plant height at planting, number of leaves at planting, and number of leaves at 7 days after planting were measured. The final number of leaves, final plant height, shoot dry matter, root dry matter, and total dry matter were measured after acclimatization. Stem cuttings between 20 and 25 mm in diameter should be used to produce cassava seedlings with the rapid multiplication method. Cuttings with 6 to 8 visible leaves should be collected, and the cuttings should be planted at the end of September.

ABSTRACT Physalis angulata L. is a plant with great fruit production potential, mainly in family farms, due to its versatility and valuable products such as jellies and juice concentrates. The aim of the present study is to evaluate the effect of two cytokines - i.e., plant growth regulators 6- benzylaminopurine (BAP) and kinetin (KIN) -, in association, or not, with auxin (2,4-dichlorophenoxyacetic acid - 2.4-D), on P. angulata multiplication in vitro. The experiment followed a completely randomized design, with eighteen treatments and five repetitions, based on factorial arrangement 2 x 5 x 2. Cytokinin sources were used at concentrations: 0, 2.5, 5.0, 7.5 and 10 mg L-1; in the presence (0.05 mg L-1) or absence of 2.4-D. Explants comprised nodal segments (approximately 1 cm) deriving from Physalis seed germination in vitro. Results indicate that the growth regulator KIN, at 5 mg L-1 concentration and in the absence of auxin 2.4-D, has potential to enable longer shoot length and larger number of internodes. However, the culture medium (MS) without plant growth regulators recorded higher biomass (fresh and dry weight) and increased root rate.

RESUMO: A helmintosporiose e a ferrugem comum estão entre as principais doenças fúngicas que afetam a produção do milho. Os objetivos desse trabalho foram avaliar a suscetibilidade de dez híbridos de milho a helmintosporiose e a ferrugem comum e verificar a eficiência de fungicidas no controle de Exserohilum turcicum. No primeiro experimento utilizaram-se os híbridos Pioneer (30F53, P1630H, P2530), Monsanto (AG 8045, AG 9045), Dow AgroSciences (2A550, 2A106 e 2B587) e Syngenta (SYN7205 VIPTERA, SW 3949 TL), e no experimento de eficiência de fungicidas no controle de helmintosporiose, testou-se a eficiência dos fungicidas propiconazol, azoxistrobina, ciproconazol + azoxistrobina, protioconazol + trifloxistrobina, benzovindiflupir + azoxistrobina, ciproconazol + azoxistrobina + mancozebe, no híbrido Pioneer P1630H. Em ambos os experimentos avaliaram-se a severidade foliar das doenças (%), o rendimento e o peso de mil sementes. O delineamento experimental foi em blocos ao acaso com quatro repetições. Os híbridos SYN7205, P2530, SW 3949 TL, 2B587, AG 9045, 2A550, P1630H, 2A106 e AG 8025 apresentam as menores áreas abaixo da curva de progresso de severidade de ferrugem comum. Os híbridos AG9045, 30F53 e 2A550 apresentam as menores áreas abaixo da curva de progresso de helmintosporiose. Os híbridos AG8025, 2B587, P1630H, AG9045, 2A106 e 2A550 apresentam os maiores rendimentos. Os fungicidas protioconazol + trifloxistrobina apresentam a maior eficiência de controle químico de helmintosporiose e a menor AACPD.

ABSTRACT: Northern corn leaf blight (NCLB) and common rust are among the primary fungal diseases affecting maize production. This study aimed to evaluate the susceptibility of ten maize hybrids to NCLB and to common rust and to verify the efficiency of fungicides in the chemical control of Exserohilum turcicum. In the first experiment, hybrids Pioneer (30F53, P1630H, P2530), Monsanto (AG 8045, AG 9045), Dow AgroSciences (2A550, 2A106 and 2B587) and Syngenta (SYN7205 VIPTERA, SW 3949 TL) were used and in the experiment for effectiveness of fungicides in the control of NCLB. The efficiency of fungicides propiconazole, azoxystrobin, cyproconazole + azoxystrobin, prothioconazole + trifloxystrobin, benzovindiflupir + azoxystrobin, cyproconazole + azoxystrobin + mancozeb were tested in the Pioneer P1630H hybrid. In both experiments, the leaf disease severity (%), yield and the weight of one thousand seeds were evaluated. The experimental design was carried out in randomized blocks with four replicates. The hybrids SYN7205, P2530, SW 3949 TL, 2B587, AG 9045, 2A550, P1630H, 2A106 and AG 8025 showed the smallest areas under the common rust severity progress curve. Hybrids AG9045, 30F53, and 2A550 presented the smallest areas under the NCLB progress curve. Hybrids AG8025, 2B587, P1630H, AG9045, 2A106, 2A550, present the highest yields. The fungicides prothioconazole + trifloxystrobin present the highest chemical control efficiency for NCLB and the lowest area under the disease progress curve (AUDPC).

RESUMO O objetivo deste trabalho foi avaliar a influência da poda da haste principal de plantas de calêndula na produção de capítulos florais. O experimento foi conduzido em blocos casualizados, com cinco repetições. Foram estudados os seguintes estágios de supressão da haste principal: testemunha (sem poda), acima de 10 folhas, acima de 15 folhas e botão floral visível; também foram avaliadas três épocas de colheita: julho, agosto e setembro, constituindo o arranjo do experimento em esquema fatorial 4x3. Foram avaliados o diâmetro, o número, e a massa de matéria fresca e seca de capítulos. Houve efeito significativo da poda da haste principal na matéria fresca e seca de capítulos, quando realizada no momento em que a planta possui mais de 15 folhas e apresenta botão floral visível. A colheita no mês de setembro caracterizou-se como a mais adequada, pois apresentou o maior diâmetro, número, e massa de matéria fresca e seca de capítulos florais.

ABSTRACT The purpose of this work was to evaluate the influence of cutting the apex of the main stem of marigold plants on floral capitula yield. The experiment was carried out in a randomized complete block design, with five replicates. The following removal stages of the main stem apexes were studied: control (without pruning), up to 10 leaves, up to 15 leaves and visible flower bud. Three harvest periods were also evaluated: July, August and September, composing a factorial experiment in a 4x3 arrangement. The diameter, number, fresh matter and the dry capitula were evaluated. The most significant effect of cutting the apex of the main stem on fresh and dry matter of the capitula was obtained when the technique was performed at the time the plants had up to 15 leaves and visible flower bud. The harvesting performed in September showed to be the most promising, since it presented the larger diameter, higher number and higher fresh matter and the dry capitula.

A utilização de espécies vegetais para cobertura do solo capazes de fornecer nutrientes e proteção ao solo é importante para a sustentabilidade dos sistemas agrícolas. O objetivo deste trabalho foi avaliar a produção de massa verde e seca, o teor e o acúmulo de nutrientes em plantas de cobertura de verão. O delineamento experimental foi de blocos casualizados, com sete tratamentos (capim-sudão, crotalária, feijão-de-porco, guandu-anão, trigo-mourisco, mucuna-preta e pousio) e seis repetições. Avaliou-se a produção de massa fresca e seca, teor e acúmulo de macronutrientes e micronutrientes na parte aérea das plantas de cobertura. Os maiores teores de nutrientes foram obtidos com o cultivo de leguminosas. A crotalária e o feijão-de-porco apresentaram por seu lado maior produção de massa seca e acúmulo de macronutrientes e micronutrientes.

The utilization of plant species for ground cover in order to supply nutrients and protect the soil is important for the sustainability of agricultural systems. The objective of this study was to evaluate the production of fresh and dry matter, and the content and accumulation of nutrients in summer cover crops. The experimental design was of randomized blocks, with seven treatments (sudan grass, crotalaria, jack beans, pigeon pea, buckwheat, velvet bean and fallow) and six replications. The parameters evaluated in the cover crops were the fresh and dry matter yield and the content and accumulation of macronutrients and micronutrients in the above-ground biomass of the plants. The highest levels of nutrients were obtained in the legume crops. The crotalaria and jack beans had both higher dry matter yield and accumulation of macronutrients and micronutrients.

RESUMO O objetivo neste trabalho foi avaliar a consorciação entre alface (Veneranda) e cebola (Baia Periforme) em diferentes espaçamentos entre linhas de cultivo. O experimento foi conduzido em delineamento blocos casualizados com quatro repetições. Foram estudadas formas de cultivo (monocultivo e consórcio de alface e cebola) e espaçamentos entre linhas (20, 35 e 50 cm), no esquema fatorial 3x3. Foram avaliados o diâmetro, massa fresca da parte aérea e número de folhas da alface. Para a cebola foram avaliadas a massa fresca e o diâmetro de bulbos. A forma de cultivo solteiro ou consorciado não afetou o desenvolvimento da alface. Porém, o diâmetro, massa fresca da parte aérea e o número de folhas foram superiores no espaçamento de 20 cm entre linhas. O diâmetro e massa fresca de bulbos de cebola quando consorciados com a alface não apresentaram diferença nos espaçamentos testados. As plantas foram beneficiadas no sistema consorciado quando cultivadas nos espaçamentos de 20 e 35 cm entre linhas de cultivo.

ABSTRACT The objective was to evaluate the intercropping of lettuce (Veneranda) and onion (Baia Periforme) under different spacings between cultivation lines. The research was carried out in a randomized block design with four replications. Forms of cultivation were studied (monoculture and intercropping of lettuce and onions) and row spacing (20, 35 and 50 cm) in a 3x3 factorial scheme. Diameter, fresh weight of the aboveground part and number of lettuce leaves were evaluated. For onion, fresh mass and bulb diameter were evaluated. The form of cultivation, single or intercropped, did not affect the development of lettuce. However, diameter, fresh weight of the aboveground part and number of leaves were higher under the 20 cm spacing between rows. Diameter and fresh weight of onion bulbs when intercropped with lettuce showed no difference in the tested spacings. Plants benefited from the intercropping system when grown under 20 and 35 cm between cultivation lines.

RESUMO Culturas de cobertura são fundamentais para a sustentabilidade do sistema plantio direto por garantir a cobertura do solo e por proporcionar benefícios para a cultura subsequente. O presente trabalho teve o objetivo de avaliar a produção de biomassa, o teor e acúmulo de nutrientes por plantas de cobertura de inverno. O delineamento experimental foi o de blocos casualizados, com seis tratamentos: nabo forrageiro, ervilhaca, aveia preta, ervilhaca + aveia preta, ervilhaca + nabo forrageiro e pousio, com quatro repetições. O cultivo solteiro de aveia preta, nabo forrageiro e o consórcio de aveia preta + ervilhaca e ervilhaca + nabo forrageiro apresentam maior produção de matéria seca. O consórcio ervilhaca + nabo forrageiro demonstra desempenho superior quanto à ciclagem dos nutrientes, com maiores acúmulos de N, P, K, Ca, Mg, S, Cu, Zn, Fe, Na e B.

ABSTRACT Cover crops are of fundamental importance for the sustainability of the no-tillage system, to ensure soil coverage and to provide benefits for the subsequent crop. The objective of this study was to evaluate the production of biomass and the content and accumulation of nutrients by winter cover crops. The experimental design used in the experiment was a randomized complete block with four replications and six treatments: oilseed radish, vetch, black oats, vetch + black oats, vetch + oilseed radish and fallow. Black oat, oilseed radish in single cultivation and black oat + vetch and vetch + oilseed radish intercroppings showed higher dry matter production. Vetch + oilseed radish intercropping demonstrates higher performance regarding cycling of nutrients, with higher accumulations of N, P, K, Ca, Mg, S, Cu, Zn, Fe, Na and B.