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 The objective of this work was to evaluate the tolerance of soybean (Glycine max) cultivars to flooding stress at different growth stages. The experiment was arranged in a 2x2x5 factorial arrangement, with two sowing dates (October and November), two soybean cultivars (TECIRGA 6070RR and NA 5909 RG), and five growth stages (SE-EM, EM-VC, VC-V2, V2-V4, and V6-V8) in the 2018/2019 and 2019/2020 crop years. The experimental design was completely randomized with four replicates. For both evaluated soybean cultivars, the growth stage most sensitive to soil flooding was SE-EM. After seedling emergence, the highest reductions in leaf area and shoot dry matter were observed in the V2-V4 stage, regardless of cultivar, sowing date, and crop year. From the V4 stage onwards, soybean shows a higher tolerance to flooding conditions. However, after seedling emergence, the TECIRGA 6070RR cultivar has a higher tolerance to flooding stress than NA 5909 RG. Sowing in October tends to reduce the impact of flooding stress on the plants.

Resumo O objetivo deste trabalho foi avaliar a tolerância de cultivares de soja (Glycine max) ao estresse por alagamento, em diferentes estádios de crescimento. O experimento foi realizado em arranjo fatorial 2x2x5, com duas épocas de semeadura (outubro e novembro), duas cultivares de soja (TECIRGA 6070RR e NA 5909 RG) e cinco fases de desenvolvimento (SE-EM, EM-VC, VC-V2, V2-V4 e V6-V8), nos anos agrícolas 2018/2019 e 2019/2020. O delineamento experimental foi inteiramente casualizado com quatro repetições. Para ambas as cultivares avaliadas, o estádio de crescimento mais sensível ao alagamento do solo foi o SE-EM. Após a emergência das plântulas, as maiores reduções de área foliar e matéria seca de brotos foram observadas no estádio V2-V4, independentemente de cultivar, época de semeadura e ano agrícola. A partir do estádio V4, a soja apresenta maior tolerância às condições de alagamento. No entanto, após a emergência das plântulas, a cultivar TECIRGA 6070RR apresenta maior tolerância ao estresse por inundação do que a NA 5909 RG. A semeadura em outubro tende a reduzir o impacto do estresse por inundação nas plantas.

Resumo O sucesso da produção e da qualidade das hastes florais de gérbera depende, principalmente, dos fatores ambientais e do correto manejo da adubação. O objetivo do trabalho foi avaliar a variação da produção e da qualidade de hastes florais de gérbera de corte cultivada em substrato à base de casca de pinus durante 28 meses (sendo 25 meses de colheita), com diferentes doses de nitrogênio (N) e cálcio (Ca). O experimento foi conduzido em ambiente protegido, e consistiu da combinação de três doses de N L-1 de substrato (0,07 g, 0,15 g e 0,2 g) e de três doses de Ca L-1 de substrato (0,02 g, 0,03 g e 0,04 g), aplicadas a cada 15 dias, além da testemunha, sem adubação com N e Ca. A maior produção e a melhor qualidade das hastes florais por planta ocorreram nos meses com temperatura do ar média entre 20 ºC e 25 ºC. A produção de hastes florais planta-1 mês-1 e o diâmetro do capítulo tiveram os máximos valores obtidos com 0,14 g de N L-1 de substrato. Já para as doses de Ca, observou-se um ajuste linear positivo significativo, ou seja, os maiores valores foram obtidos com a dose de 0,04 g de Ca L-1 de substrato. Ocorre variação mensal da produção e da qualidade das hastes florais de gérbera de corte cultivada em substrato comercial, à base de casca de pinus, e é independente do uso de diferentes doses de nitrogênio e de cálcio.

Abstract Success in production and quality of gerbera flower stalks over time depends on environmental factors and on appropriate fertilization procedures. The objective of the present work was to evaluate the production and quality of flower stalks of gerberas as cut flower cultivated for 28 months (with 25 months of harvest) in a pine bark-based substrate supplemented with different doses of nitrogen and calcium. The experiment was conducted in a greenhouse. Three doses of nitrogen (N) (0.07 g, 0.15 g and 0.20 g L-1 substrate) and three doses of calcium (Ca) (0.02 g, 0.03 g and 0.04 g L-1 substrate) were applied every 15 days along the cultivation period. The control was considered an additional treatment to which neither N nor Ca was supplemented to the plants in the pots. Highest flower yields and best flower quality were obtained in months in which the temperatures were in the range of 20 ºC to 25 ºC. The highest number of floral stalks and the largest diameter of the capitulum had a significant quadratic adjustment according to N doses. The maximum values were obtained with 0.14 g of N L-1 substrate. Whereas for Ca fertilization, a significant positive linear adjustment was determined, i.e., the highest values were obtained with the highest dose (0.04 g Ca L-1 substrate). There was a monthly variation in the yield and quality of cut gerberas grown in commercial substrate based on pine bark regardless of the different doses of nitrogen and calcium used in the experiment.

Resumo O objetivo deste trabalho foi avaliar a resposta das cultivares de feijão (Phaseolus vulgaris) Triunfo, Garapiá e BRS-FC104 ao déficit hídrico representado pela fração de água transpirável no solo (FATS). O delineamento experimental foi inteiramente casualizado, em arranjo bifatorial 3×2 (cultivares × irrigação e sem irrigação). Avaliaram-se a transpiração, o crescimento e a produtividade na safra e na safrinha. Na safra, com baixa demanda atmosférica do ar (inferior a 15 hPa em 55% dos dias), 'Garapiá' apresentou fechamento precoce dos estômatos com FATS crítica (FATSc) de 0,36, mas teve a mesma produtividade que 'Triunfo', cujos estômatos fecharam tardiamente (FATSc = 0,23). Na safrinha, com alta demanda atmosférica do ar (superior a 15 hPa em 83,3% dos dias), 'Garapiá' apresentou fechamento estomático precoce (FATSc = 0,17) e maior produtividade (392,2 kg ha−1 a mais que 'Triunfo'). Na safra e na safrinha, 'Garapiá' apresentou tolerância ao déficit hídrico no período reprodutivo. O déficit hídrico resultou em menores valores de estatura, massa seca da parte aérea, massa seca da raiz e área foliar. Tanto 'Garapiá' como 'Triunfo' apresentaram alta produtividade na safra, mas apenas Garapiá na safrinha. 'Garapiá' apresenta tolerância ao déficit hídrico, com controle estomático eficiente e com altos crescimento e produtividade.

Abstract The objective of this work was to evaluate the response of the Garapiá, Triunfo, and BRS-FC104 bean (Phaseolus vulgaris) cultivars to the water deficit represented by the fraction of transpirable soil water (FTSW). The experimental design was completely randomized in a 3×2 bifactorial arrangement (cultivars × irrigation and no irrigation). Transpiration, growth, and yield were evaluated in the crop season and off-season. In the crop season, with a low atmospheric air demand (below 15 hPa in 55% of the days), 'Garapiá' presented early stomatal closure with the critical FTSW (FTSWc) of 0.36, but had the same yield as 'Triunfo', whose stomata closed late (FTSWc = 0.23). In the off-season, with a high atmospheric air demand (greater than 15 hPa in 83.3% of the days), 'Garapiá' presented an early stomatal closure (FTSWc = 0.17) and a higher yield (392.2 kg ha-1 more than 'Triunfo'). In the crop season and off-season, 'Garapiá' showed tolerance to water deficit in the reproductive period. Water deficit resulted in lower values of height, shoot dry mass, root dry mass, and leaf area. Both 'Garapiá' and 'Triunfo' showed a high yield in the crop season, but only 'Garapiá' in the off-season. 'Garapiá' presents tolerance to water deficit, with efficient stomatal control and high growth and yield.

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. 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.

RESUMO: O objetivo desta pesquisa foi realizar um levantamento, através dos níveis de pureza física, em percentagem de sementes puras, número de outras sementes, e qualidade fisiológica através da germinação, nas amostras de sementes de azevém analisadas nos laboratórios credenciados pelo Ministério da Agricultura, Pecuária e Abastecimento do Rio Grande do Sul. Foram compilados os dados de 3959 amostras de azevém, analisadas do período de 2014 a 2017. A qualidade das sementes foi apresentada através da porcentagem de amostras dentro dos padrões recomendados para comercialização, para as variáveis germinação, sementes puras, sementes de espécies cultivadas, silvestres, nocivas toleradas e nocivas proibidas, dentro dos fatores como cultivar, região de procedência, categoria e safra de produção da semente. A qualidade dos lotes de sementes de azevém, analisados pelos laboratórios do Rio Grande do Sul, obteve na safra de 2013 menor porcentagem de lotes aprovados para comercialização, 57,96%, e as safras 2014, 2015 e 2016 com 89,60%, 91,39% e 91,34%, respectivamente. Em regiões em que há predomino da pecuária a porcentagem de lotes de sementes de azevém aprovados para comercialização foi menor.

ABSTRACT: The objective of this research was to carry out a survey, through the levels of physical purity, percentage of pure seeds, number of other seeds, and the physiological quality through germination, in the samples of ryegrass seeds analyzed in laboratories accredited by the Ministry of Agriculture, Livestock and Supply in Rio Grande do Sul. Data from 3959 ryegrass samples analyzed from the period 2014 to 2017 were compiled. Quality of the seeds was presented through the percentage of samples within the standards recommended for commercialization, for the variables germination, pure seeds, seeds of cultivated species, wild, noxious, tolerated and noxiously forbidden, in all factors, cultivar, region of origin, category and crop of seed production. Quality of the lots of ryegrass seeds, analyzed by the laboratories of Rio Grande do Sul, obtained in the harvest of 2013 the lowest percentage of lots approved for commercialization, 57.96%, and the harvest of 2014, 2015 and 2016 with 89.60% 91.39% and 91.34%, respectively. In regions where livestock predominates, the percentage of ryegrass seed lots approved for commercialization was lower.

Resumo A conservação das hastes florais cortadas tem como finalidade prolongar a durabilidade, manter a qualidade e reduzir as perdas após a colheita, propiciando um período maior de vida útil e comercialização. Assim, o objetivo deste trabalho foi avaliar a qualidade e a durabilidade na pós-colheita de hastes florais frescas de cártamo (Carthamus tinctorius L.) colhidas em diferentes épocas e submetidas a diferentes soluções conservantes. O experimento foi conduzido em delineamento inteiramente casualizado e, organizado em esquema fatorial 4x8 (quatro soluções conservantes e oito épocas de colheita), com quatro repetições, sendo cada unidade experimental constituída de cinco hastes florais. O cultivo das hastes florais de cártamo ocorreu no Setor de Floricultura e as épocas de colheita das mesmas foram realizadas no início da floração a partir da semeadura realizada na primeira quinzena estacional: no inverno, primavera e verão de 2016, outono, inverno, primavera e verão de 2017 e outono de 2018. E, as soluções conservantes foram: água destilada (testemunha); água destilada + sacarose 2%; água destilada + hipoclorito de sódio 2% e água destilada + sacarose 2% + hipoclorito de sódio 2%. As hastes florais foram avaliadas quanto a notas de qualidade, desidratação e absorção das soluções conservantes. Observou-se que as hastes florais de cártamo apresentaram vida de vaso em média de nove dias, com absorção de solução na média de 0,021 mL dia−1 g−1 de massa fresca e que o uso dos conservantes não foi benéfico à conservação em pós-colheita.

Abstract The conservation of the cut flower stems aims to prolong durability, maintain the quality and reduce the losses after harvest, providing a greater period of lifespan and commercialization. Thus, the objective of this work was to evaluate the quality and durability in post-harvest of fresh safflower (Carthamus tinctorius L.) flower stems harvested in different times and submitted to different preservative solutions. The experiment was conducted in entirely randomized design and, organized in 4x8 (four preservative solutions and eight harvest seasons) factorial scheme, with four repetitions, and each experimental unit consisting of five floral stems. The cultivation of floral stems of safflower occurred at Floriculture Sector and the harvest seasons of them were carried out in the beginning of flowering from the sowing performed in the first seasonal half: in winter, spring and summer of 2016, autumn, winter, spring and summer of 2017 and autumn of 2018. And, the preservative solutions were: distilled water (control); distilled water + sucrose 2%; distilled water + sodium hypochlorite 2% and distilled water + sucrose 2% + sodium hypochlorite 2%. The floral stems were evaluated in relation to quality notes, dehydration and absorption of preservative solutions. We observed that the floral stems of safflower presented shelf life in average of nine days, with absorption of solution in average of 0.021 mL day−1 g−1 of fresh mass and that the use of preservatives was not beneficial to conservation in post-harvest.

ABSTRACT The variability within rows of cultivation may reduce the accuracy of experiments conducted in a complete randomized block design if the rows are considered as blocks, however, little is known about this variability in protected environments. Thus, our aim was to study the variability of the fresh mass in lettuce shoot, growing in protected environment, and to verify the border effect and size of the experimental unit in minimizing the productive variability. Data from two uniformity trials carried out in a greenhouse in autumn and spring growing seasons were used. In the statistical analyses, it was considered the existence of parallel cultivation rows the lateral openings of the greenhouse and of columns perpendicular to these openings. Different scenarios were simulated by excluding rows and columns to generate several borders arrangements and also to use different sizes of the experimental unit. For each scenario, homogeneity test of variances between remaining rows and columns was performed, and it was calculated the variance and coefficient of variation. There is variability among rows in trials with lettuce in plastic greenhouses and the border use does not bring benefits in terms of reduction of the coefficient of variation or minimizing the cases of heterogeneous variances among rows. In experiments with lettuce in a plastic greenhouse, the use of an experimental unit size greater than or equal to two plants provides homogeneity of variances among rows and columns and, therefore, allows the use of a completely randomized design.

Resumo: O objetivo deste trabalho foi avaliar a dinâmica populacional do percevejo-do-colmo (Tibraca limbativentris) no entorno e na área de cultivo de arroz irrigado por inundação, quantificar o fluxo populacional do percevejo entre lavouras e plantas hospedeiras, e determinar a influência da espécie, do diâmetro da planta e da distância da planta hospedeira da bordadura sobre a população do percevejo-do-colmo. O trabalho foi conduzido na safra 2012/2013 e na entressafra, com amostragem de plantas de arroz, Andropogom bicornis e A. lateralis em seis áreas de cultivo, para a contagem do número de insetos. A densidade populacional do percevejo-do-colmo em arroz irrigado e plantas hospedeiras alternativas apresenta dependência espacial e temporal. Nas áreas de cultivo, a densidade populacional do percevejo-do-colmo aumenta de acordo com a evolução dos estádios fenológicos do arroz, com as maiores densidades concentradas em regiões próximas às suas bordaduras. O diâmetro e a espécie da planta hospedeira influenciam a população do percevejo-do-colmo. Andropogon bicornis apresenta maiores densidades populacionais que A. lateralis e plantas com maiores diâmetros apresentam maiores densidades populacionais do percevejo-do-colmo. Durante a entressafra, a maior população do inseto em plantas hospedeiras se concentra até 45 m da bordadura, mas é capaz de se dispersar até 150 m.

Abstract: The objective of this work were to evaluate the population dynamics of the rice stem bug (Tibraca limbativentris) around and in flood irrigated rice cultivation area, to quantify the insect population flow between crops and host plants, and to determine the effect of the species, the diameter of the plant, and the distance of the host plant from the border on the rice stem bug population. The work was conducted in the 2012/2013 harvest and in the off-season, with sampling of rice, Andropogom bicornis, and Andropogon lateralis plants in six cultivated areas, in order to count the number of insects. The population density of the rice stem bug in irrigated rice and alternative host plants presents spatial and temporal dependence. In the cultivated areas, the population density of the rice stem bug increases according to the evolution of the rice phenological stages, with the highest densities concentrated in regions close to the crop borders. The diameter and species of the host plant affect the rice stem bug population. Andropogon bicornis plants have higher population densities than A. lateralis, and plants with larger diameters show higher population densities of the rice stem bug. In the off-season, the greatest population of the rice stem bug on host plants is concentrated up to 45 m from the crop border, but it can disperse until 150 m.

RESUMO: Conhecer a variabilidade dentro de ambientes protegidos é crucial para a escolha do delineamento experimental a ser utilizado nestas condições. O objetivo do estudo foi avaliar a variabilidade de produção de frutos em ambiente protegido cultivado com tomate cereja e, verificar o efeito do uso de bordaduras e tamanho de parcela na redução dessa variabilidade. Para isso, dados de um teste de uniformidade realizado em estufa com tomate cereja cv. ‘Lili’ foram utilizados. A massa fresca total de frutos por planta foi considerada, sendo estas plantas dispostas em fileiras de cultivo paralelas às aberturas laterais da estufa e, também, foram dispostas em colunas perpendiculares a estas aberturas. Para gerar as bordaduras, diferentes cenários foram projetados excluindo linhas e colunas, usando diferentes tamanhos de parcela. Em cada cenário, a homogeneidade das variâncias entre as fileiras e colunas restantes foi testada. Não há variabilidade na produção de frutos entre fileiras ou colunas em ensaios com tomate cereja, realizado em estufas, sendo que o uso de bordaduras não traz benefícios em termos de redução do coeficiente de variação ou dos casos de heterogeneidade de variância entre fileiras ou colunas. As parcelas com um tamanho igual ou superior a duas plantas tornam possível utilizar o delineamento inteiramente casualizado nos ensaios com tomate cereja em estufas.

ABSTRACT: Knowing the productive variability within protected environments is crucial for choosing the experimental design to be used in that conditions. Thus, the aim of the present study was to assess the variability of fruit production in protected environment cultivated with cherry tomatoes and to verify the border effect and plot size in reducing this variability. To this, data from an uniformity test carried out in a greenhouse with cherry tomato cv. ‘Lili’ were used. Total fresh mass of fruits per plant was considered being these plants arranged in cropping rows parallel to the lateral openings of the greenhouse and also the same plants arranged in columns perpendicular to these openings. To generate the borders, different scenarios were designed by excluding rows and columns and using different plot sizes. In each scenario, homogeneity of variances among the remaining rows and columns was tested. There is no variability of fruit production among rows or columns in trials with cherry tomatoes carried out in greenhouses and the use of border does not bring benefits in terms of reduction of coefficient of variation or reduction of cases of variance heterogeneity among rows or columns. Plots with a size equal to or greater than two plants make possible to use the completely randomized design in the cherry tomato trials in greenhouses.

RESUMO O objetivo deste trabalho foi ajustar curvas de crescimento e determinar o plastocrono e o número final de nós de mudas de cravina de jardim, cultivadas em diferentes substratos. Um total de 392 plantas foram cultivadas em sete substratos em casa de vegetação, em Santa Maria, RS. As curvas de crescimento foram ajustadas ao modelo logístico, e o plastocrono foi estimado pelo inverso do coeficiente angular da regressão linear simples entre o número de nós acumulados e a soma térmica acumulada a partir da repicagem das mudas. O ajuste do modelo logístico foi melhor para a variável número de folhas que para altura de plantas, em todos os substratos. As plantas dos substratos 50% de solo + 50% de cinzas de casca de arroz; e 80% cinzas de casca de arroz + 20% húmus de minhoca tiveram os maiores ciclos de produção, 74 e 65 dias, respectivamente, e o completaram com soma térmica de 1317,9 ºC dia para número de folhas e altura de plantas. As curvas de crescimento ajustadas pelo modelo logístico e o plastocrono em cravina de jardim são dependentes do tipo de substrato utilizado, e o melhor é o comercial Mecplant®. O número final de nós na haste principal é, em média, 14 nós planta-1, para todos os substratos.

ABSTRACT The objective of this work was to plot the growth curves and determine the plastochron and the final number of nodes of China pink seedlings grown on different substrates. Thus, 392 China pink seedlings were grown on seven substrates under greenhouse conditions, in Santa Maria in the state of Rio Grande do Sul, Brazil. The growth curves were plotted using the logistic model. The plastochron was estimated by the inverse of the angular coefficient of the simple linear regression between the number of accumulated nodes and accumulated thermal sum from the subsampling of the seedlings. In all substrates, the logistic model fit better for the variable number of leaves than for the plant height. The plants in substrates with 50% of soil plus 50% of rice husk ash, and 80% of rice husk ash plus 20% earthworm humus had the longest cycles with 74 and 65 days, respectively. They completed the cycles with a thermal sum of 1317.9 ºC day for number of leaves and plant height. The growth curves that were plotted by the logistic model and the plastochron of the China pink seedlings are dependent on the type of substrate used. The commercial substrate Mecplant® had the best results. The average final number of nodes of the main stem of the plants was 14 for all substrates.

RESUMO O teste de condutividade elétrica é um teste de vigor de sementes utilizado para avaliar a qualidade das sementes e complementar o teste de germinação. O tamanho da amostra necessária para a estimação da média de condutividade elétrica de sementes é diretamente proporcional à variabilidade dos dados e confiabilidade desejada na estimativa. Uma técnica adequada para dimensionamento amostral é a utilização de intervalos de confiança, obtidos por reamostragem, com a vantagem de não dependerem da distribuição de probabilidade dos dados. O objetivo deste trabalho foi estimar o tamanho de amostra necessário para o teste de condutividade elétrica individual em sementes de girassol. Foram utilizados 7 lotes de sementes de girassol, sendo 3 da cultivar Hélio 250, 2 da cultivar BRS 323 e 2 da cultivar BRS 324. O teste de condutividade elétrica individual foi realizado com 400 sementes de cada lote, e o tamanho de amostra foi determinado pelo número de sementes a partir do qual a amplitude do intervalo de confiança de 95% (AIC95%) foi menor ou igual a 15, 20, 25, 30 e 35% da estimativa da média. O tamanho de amostra de 483, 257, 172, 115 e 85 sementes é suficiente para a estimativa da média de condutividade elétrica individual de sementes de girassol com AIC95% igual a 15, 20, 25, 30 e 35% da estimativa da média, respectivamente, para todos os lotes e períodos de embebição.

ABSTRACT The electrical conductivity is a seed vigor test used to assess seed quality and complement the germination test. The sample size required to estimate the average electrical conductivity of seeds is directly proportional to the variability of the data and desired reliability in the estimate. A suitable technique for sample dimension is the use of confidence intervals obtained by resampling. This technique has the advantage of not depending on the probability distribution of the data. The objective of this study was to estimate the sample size required for the individual electrical conductivity test in sunflower seeds. Seven lots of sunflower seeds were used: 3 lots of the cultivar Hélio 250, 2 of the BRS 323, and 2 of the BRS 324. The individual electrical conductivity test was conducted with each lot of 400 seeds, and the sample size was determined by the seed number from which the amplitude of the 95% confidence interval (AIC95%) was less than or equal to 15, 20, 25, 30, and 35% of the mean estimate. The sample size of 483, 257, 172, 115, and 85 seeds is sufficient to estimate the average of the individual electrical conductivity of sunflower seeds with an AIC95% equal to 15, 20, 25, 30, and 35% of the mean estimate, respectively, for all lots and soaking periods.

RESUMO: O objetivo deste artigo foi identificar a relação linear entre os componentes da produtividade do tomate cereja. Dois ensaios de uniformidade, sem tratamentos, foram instalados em estufas plásticas nas estações primavera/verão de 2014 com tomate cereja Lilli, com as plantas conduzidas em duas hastes. As variáveis observadas em cada planta foram o comprimento médio de fruto, a sua largura média, o peso médio seu, o número de cachos, o número de frutos por cacho, o número total de frutos e o peso total de frutos, sendo estimada a matriz de correlação de Pearson entre elas. Posteriormente, foi realizada a análise de trilha considerando-se o peso total de frutos como variável principal e as demais como variáveis explicativas. Devido à multicolinearidade severa, optou-se pela eliminação da variável número de frutos por cacho. Os coeficientes de correlação de Pearson, entre as variáveis explicativas e a variável principal, foram significativos. O peso médio de frutos tem baixa relação de causa e efeito com o peso total de frutos produzidos. Também, o número de frutos e o número de cachos apresentaram baixa relação de causa e efeito entre si. A produtividade do tomate cereja está diretamente relacionada com o número de frutos por planta.

ABSTRACT: The objective of this study was to identify the linear relationship between cherry tomato yield components. Two uniformity trials, without treatments, were conducted on Lilli cherry tomato plants in a plastic greenhouse during the 2014 spring/summer season, with the plants in two stems. Variables observed for each plant were mean fruit length, mean fruit width, mean fruit weight, number of bunches, number of fruits per bunch, total number of fruits, and total fruit weight; a Pearson's correlation matrix was used to estimate the relationship between the variables. Path analysis was then performed considering total fruit weight as the main variable and the remaining variables as explanatory. Due to the severe multicollinearity, the variable 'number of fruits per bunch' was eliminated. Pearson's correlation coefficients were significant between explanatory and main variables. Mean fruit weight has a low cause-and-effect relationship with the total weight of fruits produced. A low cause-and-effect relationship was also observed between number of fruits and number of bunches. Cherry tomato productivity is directly related to the number of fruits per plant.

RESUMO: O objetivo do estudo foi caracterizar a altura (H) e o número de folhas (NF), pelo modelo logístico, de cravina de jardim cultivada em sete substratos em função da soma térmica. Foram avaliadas a H e o NF de 56 plantas por substrato, totalizando 392 plantas ajustadas. As plantas dos substratos compostos de: 50% de solo e 50% de cinzas de casca de arroz (50% S + 50% CA); e 80% cinzas de casca de arroz e 20% húmus de minhoca (80% CA + 20% H) tiveram o maior ciclo, de 74 dias, e o completaram com soma térmica de 1317,9ºC dia. O modelo logístico ajustado para H apresentou diferenças para a estimativa da altura máxima esperada (α) entre os substratos, com valores de 10,47cm para 50% S + 50% CA e, 35,75cm, para o substrato Mecplant(r). Para o NF, observou-se que α teve menor variação entre os substratos, desde aproximadamente 30 folhas, nas plantas do substrato 50% S + 50% CA até 34 folhas, nas plantas do substrato 80% CA + 20% H. O crescimento de cravina de jardim, a partir das variáveis estudadas, pode ser caracterizado pelo modelo logístico, em função da soma térmica acumulada, quando as plantas estão sem restrições nutricionais. Considerando a altura máxima e o número máximo de folhas, os melhores substratos foram o composto de 80% de solo + 20% húmus de minhoca e o Mecplant(r). Entretanto, os usuários devem testar as calibrações do modelo, com os parâmetros sugeridos, antes de aplicar o modelo para outras condições climáticas.

ABSTRACT: The objective of this study was to characterize the height (H) and leaf number (LN) of China pinks, grown in seven substrates, as a function of degree days, using the logistic growth model. H and LN were measured from 56 plants per substrate, for 392 plants in total. Plants that were grown on substrates formed of 50% soil with 50% rice husk ash (50% S + 50% RH) and 80% rice husk ash with 20% worm castings (80% RH + 20% W) had the longest vegetative growth period (74d), corresponding to 1317.9ºCd. The logistic growth model, adjusted for H, showed differences in the estimation of maximum expected height (α) between the substrates, with values between 10.47cm for 50% S + 50% RH and 35.75cm for Mecplant(r). When α was estimated as LN, variation was also observed between the different substrates, from approximately 30 leaves on plants growing on 50% S + 50% RH to 34 leaves on the plants growing on the substrate formed of 80% RH + 20% W. Growth of China pinks can be characterized using H or LN in the logistic growth model as a function of degree days, being the provided plants adequately fertilized. The best substrates in terms of maximum height and leaf number were 80% soil + 20% worm castings and Mecplant(r). However, users must recalibrate the model with the estimated parameters before applying it to different growing conditions.