Resumo: Os nutrientes minerais desempenham importante papel na composição das sementes, influenciando a taxa de germinação e a produção de plântulas vigorosas, o que é fundamental para o estabelecimento do estande de plantas e produtividade da cultura. O objetivo deste trabalho foi avaliar o efeito da adubação fosfatada sobre o teor de fósforo (P) e a qualidade fisiológica de sementes de cultivares de trigo. Foi utilizado delineamento em parcelas subdivididas 2 × 16, sendo duas doses de P (0 e 140 kg.ha-1) e 16 genótipos de trigo (cultivares BR 18, BR 23, BRS 208, BRS 254, BRS 264, BRS 404, BRS Graúna, BRS Pardela, BRS Sabiá, WT 15025, CD 118, IPR Catuara, Ocepar 14, Supera, TBIO Bandeirante e TBIO Iguaçu). Foram avaliados: primeira contagem, germinação, envelhecimento acelerado, emergência e comprimento de plântulas, condutividade elétrica, índice de velocidade de emergência, teor de P nas sementes e massa de mil sementes. Os dados de doses de P e genótipos de trigo foram submetidos à análise de variância e à comparação de médias pelo teste F e teste de Scott-Knott, respectivamente. As sementes da BR 18 e Ocepar 14 apresentaram maior qualidade fisiológica, enquanto as sementes da TBIO Iguaçu, CD 118 e BRS Sabiá apresentaram menor vigor. A adubação fosfatada proporciona a produção de sementes de trigo com maior teor de P e qualidade fisiológica, mas não influência a massa de mil sementes da maioria das cultivares de trigo.

Abstract: Mineral nutrients play an important role in the composition of seeds, influencing the germination rate and the production of vigorous seedlings, which is fundamental for the establishment of the plant stand and crop yield. This work aimed to evaluate the effect of phosphate fertilization on phosphorus (P) content and the physiological quality of seeds of wheat cultivars. A 2 × 16 split plot design was used, with two rates of P (0 and 140 kg.ha-1) and 16 wheat genotypes (cultivars BR 18, BR 23, BRS 208, BRS 254, BRS 264, BRS 404, BRS Graúna, BRS Pardela, BRS Sabiá, WT 15025, CD 118, IPR Catuara, Ocepar 14, Supera, TBIO Bandeirante and TBIO Iguaçu). The evaluation includes: first count, germination, accelerated aging, seedling emergence and length, electrical conductivity, emergence speed index, P content in seeds, and thousand-seed weight. The data of P rates and wheat genotypes were subject to analysis of variance and to the comparison of means by the F-test and Scott-Knott test, respectively. The seeds of BR 18 and Ocepar 14 showed higher physiological quality, whereas the seeds of TBIO Iguaçu, CD 118, and BRS Sabiá showed lower vigor. Phosphate fertilization provides the production of wheat seeds with higher P content and physiological quality, but it does not influence the thousand-seed weight of most wheat cultivars.

Resumo: A combinação ótima entre densidade de semeadura e dose de nitrogênio (N) na adubação é um desafio para a produção de sementes de alta qualidade, considerando a diversidade de genótipos e ambientes. O objetivo deste trabalho foi avaliar o rendimento e a qualidade fisiológica de sementes de trigo em função da densidade de semeadura e dose de N, em diferentes condições edafoclimáticas. O experimento foi conduzido em três ambientes (Londrina, Cascavel e Ponta Grossa) em delineamento em blocos casualizados com quatro repetições, considerando um arranjo fatorial 2 × 3 × 4 composto por dois genótipos (BRS Anambé e WT 15-025), três densidades de semeadura (250, 350 e 450 sementes.m-2) e quatro doses de N (0, 40, 80 e 120 kg.ha-1). Foram avaliadas as seguintes características de sementes: rendimento, primeira contagem de germinação, germinação final de sementes, emergência de plântulas, índice de velocidade de emergência, comprimento de plântula e massa seca de plântula. O rendimento de sementes variou em função do ambiente e do genótipo. BRS Anambé produziu sementes com maior qualidade fisiológica. A combinação ótima entre densidade de semeadura e dose de N que proporcionou o rendimento econômico mais adequado, sem afetar a qualidade fisiológica de sementes de trigo, variou com o ambiente e foi estimada em 250 sementes.m-2 × 0 kg.ha-1 N para Londrina e Cascavel, e 350 sementes.m-2 × 18 kg.ha-1 N para Ponta Grossa.

Abstract: The optimal combination between sowing density and nitrogen (N) fertilization rate is a challenge for the production of high-quality seeds, considering the diversity of genotypes and environments. This study aimed to evaluate the yield and physiological quality of wheat seeds as a function of sowing density and N rate, under different edaphoclimatic conditions. The experiment was carried out in three environments (Londrina, Cascavel, and Ponta Grossa) in a randomized block design with four replications, considering a 2 × 3 × 4 factorial arrangement composed of two genotypes (BRS Anambé and WT 15-025), three sowing densities (250, 350, and 450 seeds.m−2), and four N rates (0, 40, 80, and 120 kg.ha−1). The following seed features were evaluated: yield, first germination count, final seed germination, seedling emergence, emergence speed index, seedling length, and seedling dry matter. Seed yield varied as a function of environment and genotype. BRS Anambé produced seeds with higher physiological quality. The optimal combination between sowing density and N rate that provided the more suitable economic yield, without affecting the physiological quality of wheat seeds, varied with the environment and was estimated in 250 seeds.m−2 × 0 kg.ha−1 N for Londrina and Cascavel, and 350 seeds.m−2 × 18 kg.ha−1 N for Ponta Grossa.

ABSTRACT Increases in plant density associated with the use of plant growth regulators, aside from modifying the plant architecture, can also change the maize yield performance. This study aims to investigate the yield components and grain yield of maize hybrids with contrasting leaf architecture, in response to different plant populations and trinexapac-ethyl rates (TE). Field experiments were conducted in two growing seasons, in a (5 x 5) factorial randomized block design. The treatments consisted of: five plant population (40, 60, 80, 100, and 120 thousand plants ha-1) and five TE rates (0, 100, 200, 300, and 400 g a.i. ha-1), with four replications, using the hybrids 2B710 HX and Status TL. We evaluated the number of rows per ear, ear length, number of grains per row, 1000-grain mass, and yield. An increased plant density reduces ear length, number of grains per row and 1000-grain mass, without changing the number of grain rows per ear. TE rates increases ear length and number of grains per row and reduces 1000-grain mass, mainly under favorable cultivation conditions. TE interacts with the plant density, changing the maize yield components with increases in grain yield, but these gains variy, according to the environment and genotype characteristics.

ABSTRACT Nitrogen fertilization, besides increasing productivity, can favor the production of well-formed, large, and heavy grains, which are traits valued by the oat processing industry. However, high nitrogen (N) doses may lead to plant lodging, which could be solved by using growth retardant. This study aimed to evaluate the industrial quality of white oat grains cultivated under different nitrogen doses and associated with the growth retardant trinexapac-ethyl in two growing environments. Experiments were conducted in Londrina and Mauá da Serra, PR, Brazil, using the cultivar IPR Afrodite in a randomized block design in a 4 × 2 factorial scheme and four replications. Treatments consisted of four topdressing N doses (0, 30, 60, and 90 kg ha−1) and the application or not of growth retardant. Thousand-grain weight, hectoliter weight, grain index greater than two millimeters, peeling index, and industrial grain yield were evaluated. The effect of N fertilization and growth retardant on the industrial quality of white oat grains depends on the characteristics of the growing environment. The trinexapac-ethyl application reduces grain quality in Londrina and Mauá da Serra. However, the industrial quality of grains is high in both growing environments when the growth retardant is associated with nitrogen doses.

RESUMO O sensoriamento remoto espectral e o sensor proximal são ferramentas importantes para gerenciar a relação planta-patógeno. A falta de planejamento experimental e a probabilidade de erro em estudos agrícolas podem resultar em retrabalho e, consequentemente, despesas financeiras e de recursos humanos. Uma maneira de reduzir esse problema é determinar o tamanho ótimo de parcela experimental para realização dos tratamentos. O objetivo deste estudo foi estimar o tamanho ótimo de parcela para refletância em soja que foi tratada com diferentes doses de fungicida, usando os métodos de curvatura máxima modificada e distância máxima. As leituras de refletância foram realizadas na cultura de soja com o auxílio de um radiômetro GreenSeeker®, com unidades básicas de 0,45 m², em uma área de dez linhas, com 10 metros de comprimento, em cada tratamento. Os tratamentos foram aplicados para criar um gradiente da doença ferrugem asiática da soja, variando o número de aplicações de fungicidas. Os dados foram coletados em dois estágios fenológicos (R5.5 e R6), obtendo-se 300 simulações de áreas experimentais em cada estágio. Com base nos resultados, recomenda-se o uso de parcelas de 5,40 m², com um grupo de três linhas, com 4 m de comprimento.

ABSTRACT Spectral remote sensing and proximal sensors are important tools for managing the plant-pathogen relationship. The lack of experimental planning and the probability of error in agricultural studies may result in work repetition and, consequently, in financial expenses and costs with human resources. To reduce such problems, determining the optimum size of the experimental plot for treatments is one of the adopted methods. The objective of this study was to estimate the optimum plot size for reflectance in soybeans that were treated with different fungicide levels according to the methods of modified maximum curvature and maximum distance. Reflectance readings were carried out for the soybean crop with a radiometer GreenSeeker®, considering basic units of 0.45 m² in an area of ten rows, 10 m long, for each treatment. Treatments were applied to create a gradient of Asian soybean rust, varying the number of fungicide applications. Data were collected in two phenological stages (R5.5 and R6), obtaining 300 simulations of experimental area for each stage. Based on the results, the use of 5.40 m² plots with a group of three rows, 4 m long, is recommended.

RESUMO A interação genótipo-ambiente (GA) é um complicador para a seleção de novos genótipos. A abordagem Bayesiana é uma ferramenta que pode aumentar a eficiência das metodologias de adaptabilidade e estabilidade. Nesse contexto, o objetivo deste estudo foi avaliar os parâmetros lineares e bi-lineares da análise AMMI (Additive Main Effects and Multiplicative Interaction) pela abordagem Bayesiana na seleção de genótipos de soja tipo alimento em ensaios multi-ambientes. A produtividade de grãos de cinco linhagens livres das enzimas lipoxigenases e destinadas ao consumo humano do Programa de Melhoramento de Soja da Universidade Estadual de Londrina e duas cultivares comerciais (BRS 257 e BMX Potência RR) foram avaliadas em quatro municípios do Estado do Paraná, nas safras 2014/15, 2015/16 e 2016/17. Das linhagens avaliadas, apenas a UEL 110 e UEL 122 tiveram efeitos genotípicos a posteriori positivos, superiores a 95% de confiabilidade a cultivar comercial BRS 257. Somente as linhagens UEL 115 e UEL 123 não contribuíram significativamente para a interação GA. As linhagens UEL 110 e UEL 122 foram adaptáveis ao maior número de ambientes de interação GA significativas e, portanto, são promissoras para o desenvolvimento de novas cultivares de soja tipo alimento. A utilização da AMMI1 (CP1 vs efeitos genotípicos) mostrou resultados para a estabilidade semelhantes ao AMMI2 (CP1 vs CP2), o que possibilitou uma seleção direta pelo biplot para produtividade e estabilidade.

ABSTRACT A complicating factor for the selection of plant strains is the influence of a genotype-environment (GE) interaction. The Bayesian approach is a tool to increase the efficiency of adaptability and stability methodologies. In this context, the objective of this study was to evaluate the linear and bi-linear parameters of the additive main effects and multiplicative interaction (AMMI) analysis using the Bayesian approach for selection of food-type soybean genotypes in multi-environment trials. The grain yields of five lipoxygenase-free lines intended for human consumption of from the soybean breeding program of the Londrina State University and two commercial standards (BRS 257 and BMX Potência RR) were evaluated in four counties of the State of Paraná, Brazil, in the 2014/15, 2015/16 and 2016/17 growing seasons. Of the evaluated lines, only UEL 110 and UEL 122 had positive posterior genotypic effects, exceeding a probability of 95% against the commercial standard BRS 257. Only lines UEL 115 and UEL 123 did not contribute significantly to the GE interaction. Lines UEL 110 and UEL 122 proved adaptable to the largest number of environments with significant GE interaction and are therefore promising for the development of new food-type soybean cultivars. The use of AMMI1 (PC1 vs. effects genotypes) showed results for the stability of genotypes similar to AMMI2 (PC1 vs PC2), allowing a direct selection by the biplot for productivity and stability.

Resumo: Objetivou-se avaliar o potencial fisiológico de sementes de cultivares de aveia branca cultivadas em diferentes épocas e densidades de semeadura. Dois experimentos independentes foram conduzidos em duas épocas de semeadura, utilizando-se o delineamento experimental de blocos casualizados em esquema fatorial 4 x 2, com quatro repetições. Os tratamentos constaram de quatro densidades de semeadura (180, 240, 300 e 360 sementes viáveis.m-2) e duas cultivares (IPR Afrodite e IPR Artemis). Foram avaliados: massa de mil sementes, geminação, primeira contagem da germinação, comprimento e massa seca de plântula, índice de velocidade de emergência e emergência de plântulas em areia. Os dados foram submetidos à análise de variância conjunta para épocas de semeadura, separadamente para as cultivares. As médias de épocas foram comparadas pelo teste F e as de densidades submetidas à análise de regressão polinomial até segundo grau, a 5% de probabilidade. As sementes produzidas na primeira época de semeadura apresentam melhor vigor. O aumento da densidade de semeadura reduz a massa e o vigor das sementes produzidas na segunda época de cultivo. Para as cultivares IPR Afrodite e IPR Artemis, a utilização de 180 sementes.m-2, na primeira época de semeadura, possibilita a produção de sementes de melhor potencial fisiológico.

Abstract: The aim of this study was to evaluate the physiological potential of seeds of white oat cultivars grown at different sowing dates and densities. Two independent experiments were conducted with two different sowing dates in a randomized block experimental design in a 4 × 2 factorial arrangement, with four replications. The treatments consisted of four sowing densities (180, 240, 300, and 360 viable seed.m-2) and two cultivars (IPR Afrodite and IPR Artemis). The following evaluations were made: thousand seed weight, germination percentage, first germination count, seedling length, seedling dry matter, emergence speed index, and seedling emergence in sand. Joint analysis of variance was carried out on the data regarding sowing dates separately for the cultivars. The mean values for sowing dates were compared by the F test; and polynomial regression analysis up to the second degree at 5% probability was conducted on the densities. The seeds produced by the plants grown from the first sowing date had better vigor than those produced by plants from the later sowing date. The increase in sowing density reduces the weight and vigor of the seeds produced by plants from the second sowing date. For the IPR Afrodite and IPR Artemis cultivars, the use of 180 seed.m-2 in the first growing period allows production of seeds with greater physiological potential.

ABSTRACT: Meloidogyne species are widely distributed in coffee growing areas in Brazil, where M. paranaensis is responsible to significant losses to the crop. One of the main management strategies is the use of resistant cultivars, such as Apoatã rootstock and cultivars IPR 100 and IPR 106. However, the parasitic relationship between coffee and M. paranaensis in cultivars carrying resistance genes has been poorly understood. The objective of this paper was to characterize the resistance response of Coffea arabica cv. IPR 106 to M. paranaensis. For this, penetration and histopathological studies were carried out using root tissues parasitized by the nematode. ‘IPR 106’ and ‘Mundo Novo’ (susceptible cultivar) seedlings were inoculated with 4,000 eggs of M. paranaensis and, 15 days after inoculation (DAI), roots were stained with fuchsine to verify the penetration rates of the nematode. Histopathological studies were conducted at 15, 30, 45 and 60 DAI and nematode reproduction was calculated at 120 DAI. ‘IPR 106’ did not avoid completely nematode penetration at 15 DAI, although the number of nematodes was 50 % lower than in Mundo Novo, disregarding the hypothesis of a pre-infectional mechanism of resistance that could prevent nematode penetration completely. However, giant cells and collapsed nematodes were observed in ‘IPR 106’ at 30 DAI, suggesting that the resistance mechanism to M. paranaensis in ‘IPR 106’ involves a post-infectional response and could be mediated by a hypersensitive reaction.

RESUMO O uso de biorreguladores na agricultura pode alterar a morfologia das plantas de milho, aumentando a produtividade da cultura pela possibilidade do incremento populacional. O trabalho objetivou avaliar os efeitos de populações de plantas associadas às doses de trinexapac-ethyl (TE) sobre as características biométricas da parte aérea e a produtividade de grãos de cultivares de milho contrastantes quanto à arquitetura de plantas. Experimentos foram conduzidos a campo, em duas safras, com os híbridos 2B710 HX (folha plana) e Status TL (folha ereta), utilizando blocos casualizados (quatro repetições) com tratamentos em esquema fatorial 5 x 5, sendo cinco populações de plantas (40; 60; 80; 100 e 120 mil plantas ha-1) e cinco doses de TE (0; 100; 200; 300 e 400 g de i.a. ha-1), aplicadas via pulverização foliar no estádio V6. Foram avaliadas as alturas de plantas e de inserção da espiga, o diâmetro do colmo, o índice de área foliar e a produtividade de grãos. O incremento na população aumenta a altura de plantas, a inserção da espiga e o índice de área foliar, porém reduz o diâmetro do colmo. O biorregulador TE reduz as alturas de plantas e de inserção da espiga. A interação de população de plantas e TE favorece a produtividade do milho, com maiores valores observados nas combinações de 93,4 mil plantas ha-1 com a dose de 176 g ha-1 de TE para o híbrido 2B710 HX e 92,2 mil plantas ha-1 com a dose de 251 g ha-1 de TE para o híbrido Status TL.

ABSTRACT The use of plant growth regulators in agriculture can alter the morphology of corn plants, increasing crop yield due to the possibility of increasing the population. This study aimed to evaluate the effects of plant populations associated with trinexapac-ethyl (TE) doses on the biometric characteristics of shoot and grain yield of contrasting corn cultivars regarding plant architecture. Experiments were conducted in the field during two seasons with the hybrids 2B710 HX (flat leaf) and TL Status (erect leaf) in a randomized block design (four replications) and treatments in a 5 × 5 factorial scheme, with five plant populations (40, 60, 80, 100, and 120 thousand plants ha−1) and five TE doses (0, 100, 200, 300, and 400 g a.i. ha−1) applied by foliar spraying at the V6 stage. Plant height, ear insertion height, stem diameter, leaf area index, and grain yield were evaluated. An increment in population increases plant height, ear insertion height, and the leaf area index, but reduces stem diameter. The plant growth regulator TE reduces plant height and ear insertion height. The interaction between plant population and TE favors corn yield, with the highest values observed in combinations of 93.4 thousand plants ha−1 with a dose of 176 g ha−1 of TE for the hybrid 2B710 HX and 92.2 thousand plants ha−1 with a dose of 251 g ha−1 of TE for the hybrid Status TL.

ABSTRACT Maize is one of the species with greater genetic diversity among cereals and possibly the most diverse crop species known. Accessing this variability is essential for maize breeding, allowing breeders to achieve progress of yield increasing, overcome environmental challenges or deal with pests and diseases. Among the maize diseases, southern rust is one of the most important, causing significant losses in yield and presenting severe epidemics worldwide. In the present study, the AFLP technique was applied to analyze population structure and genetic diversity among 145 tropical maize inbred lines, and to test for preliminary evidence of association between AFLP markers and the reaction to southern rust. Disease severity was evaluated in two crop seasons and the accessions were genotyped through AFLP using four primer combinations. The clusters obtained based on the Jaccard genetic distance and Ward’s hierarchical clustering and those achieved by structure simulations had high concordance and were capable of establish two big clusters, one predominantly of common maize and another of popcorn. The association analysis was performed using four different statistical models. The more complete model containing both population structure and genetic relatedness narrowed the number of significant associations, demonstrating its importance to control false associations. A total of 19 significant marker associations were identified from which three (EactMctg18, EactMctg205, EactMctg169) are interesting candidates for further investigations.

RESUMO Objetivou-se avaliar o efeito do redutor de crescimento trinexapac-ethyl sobre a qualidade fisiológica de sementes de diferentes cultivares de aveia branca granífera, em dois ambientes de cultivo. Os experimentos foram conduzidos nos municípios de Londrina e Mauá da Serra, Paraná, sob o delineamento experimental de blocos casualizados em esquema fatorial 4 x 2, com quatro repetições. Os tratamentos constaram de quatro cultivares de aveia branca (IPR Afrodite, IPR Artemis, URS Corona e URS Guria), com e sem a aplicação do redutor de crescimento. O trinexapac-ethyl foi aplicado via pulverização foliar, na dose de 125 g i.a ha-1, no período de elongação do colmo, entre o 1º e o 2º nó perceptível. Foram avaliados: geminação, primeira contagem de germinação, comprimento e massa seca de parte aérea e de raiz de plântulas, envelhecimento acelerado, condutividade elétrica, índice de velocidade de emergência, emergência de plântulas em areia e massa de mil sementes. Ao término do estudo, verificou-se que Londrina e Mauá da Serra apresentam potencial para produção de sementes de aveia branca, com germinação acima dos padrões de comercialização da espécie; a aplicação do trinexapac-ethyl reduz o vigor de sementes das cultivares IPR Afrodite e IPR Artemis, produzidas em Londrina e Mauá da Serra, respectivamente.

ABSTRACT The aim of this study was to assess the effect of the growth retardant trinexapac-ethyl on the physiological quality of seeds of different grain white oat cultivars in two growing environments. The experiments were carried out in Londrina and Mauá da Serra, Paraná State, Brazil. The experimental design was a randomized block design in a 4 × 2 factorial scheme with four replications. Treatments consisted of four white oat cultivars (IPR Afrodite, IPR Artemis, URS Corona, and URS Guria), with and without growth retardant application. Trinexapac-ethyl was applied by foliar spraying in a dose of 125 g a.i. ha−1 at the stem elongation stage between the first and second perceptible node. The following parameters were assessed: germination, first germination count, length and dry matter of seedling shoot and root, accelerated aging, electrical conductivity, emergence rate index, seedling emergence in sand, one-thousand-seed weight. At the end of the study, Londrina and Mauá da Serra presented a production potential white oat seed with germination above the standards for the species. Trinexapac-ethyl application reduced seed vigor of the cultivars IPR Afrodite and IPR Artemis produced in Londrina and Mauá da Serra, respectively.

Resumo: Objetivou-se avaliar a qualidade fisiológica de sementes de aveia branca cultivada sob diferentes doses de nitrogênio em cobertura, associadas ao redutor de crescimento trinexapac-ethyl em dois ambientes de cultivo. Os experimentos, em Londrina-PR e Mauá da Serra-PR, foram conduzidos utilizando-se a cultivar IPR Afrodite, em delineamento experimental de blocos casualizados em esquema fatorial 4 x 2, com quatro repetições. Os tratamentos constaram de quatro doses de nitrogênio (0, 30, 60 e 90 kg.ha-1) associadas ou não ao redutor de crescimento. Foram avaliados: produtividade de sementes, massa de mil sementes, geminação, primeira contagem de germinação, comprimento e massa seca de plântulas, envelhecimento acelerado, condutividade elétrica, índice de velocidade de emergência e emergência de plântulas em areia. Os dados foram submetidos a análise de variância e, posteriormente, ao teste F e a regressão até 2° grau (p≤0.05). A aplicação do redutor de crescimento e da adubação nitrogenada de cobertura aumenta a produtividade de sementes em Mauá da Serra. A adubação nitrogenada reduz a qualidade das sementes, contudo este efeito pode ser minimizado, não observado ou sobreposto pelo efeito positivo do redutor de crescimento. Este efeito depende das características do ambiente e não foi observado em Londrina.

Abstract: The aim of this study was to evaluate the physiological quality of white oat seeds cultivated under different topdressing N levels combined with the plant growth retardant trinexapac-ethyl in two growing environments. The experiments were carried out in Londrina and Mauá da Serra Municipalities (PR, Brazil) with the cultivar ‘IPR Afrodite’. The experimental design was in randomized blocks, in a 4x2 factorial arrangement, with four replications. Treatments consisted of four N levels (0, 30, 60, and 90 kg.ha-1) combined or not with the plant growth retardant. Seed yield, 1000-seed weight, germination, first germination count, seedling length, seedling dry matter, accelerated aging, electrical conductivity, emergence speed index, and seedling emergence in sand were evaluated. Data were submitted to the analysis of variance and then to the F test and regression analysis up to the second degree (p≤0.05). The application of the plant growth retardant and N topdressing led to an increase in seed productivity in Mauá da Serra. N fertilization reduced seed quality, but this effect can be minimized, not observed or overlapped by the positive effect of the plant growth retardant. Such an effect depends on environmental characteristics and it was not observed in Londrina.

RESUMO O milho doce é uma cultura importante por causa do seu tipo de sementes com índice elevado dos açúcares totais e baixo índice do amido. Como o milho comum, este necessita de quantidade adequada de nitrogênio para atingir altas produtividades, no entanto, os estudos que envolvem nitrogênio e milho doce são realizados para o rendimento das espigas e não para a produção de sementes. Como a semente é o principal método de propagação dessa espécie, foi avaliado os efeitos das doses de nitrogênio em cobertura em diferentes estádios fenológicos para produção e potencial fisiológico de sementes de milho doce. As sementes de milho doce (variedade BR 400) foram semeadas em Latossolo e um esquema fatorial de tratamento 3 × 2 + 1 foi instalado com três doses de nitrogênio 40, 80 e 120 kg ha-1 e dois estádios fenológicos (V6 e R1) mais o controle (sem nitrogênio em cobertura). Foram avaliadas a produtividade de sementes, teores de proteína, P e Zn, germinação e vigor. Como conclusão, o nitrogênio fornecido em V6 a 120 kg ha-1 aumenta a produtividade de sementes e mantém os teores de proteína inalterados. A germinação da semente e o vigor não aumentam quando as taxas de nitrogênio são acrescidas ou fornecidas em diferentes estádios fenológicos. Diminuição ligeira do teor de P ou o aumento do teor de Zn nas sementes são observados a uma dose baixa de nitrogênio entretanto não suficientes para promover alterações no potencial fisiológico das sementes do milho doce.

ABSTRACT Sweet corn is an important crop because of its seeds with high total sugar and low starch contents. As common corn, this group requires an adequate amount of nitrogen to reach high yields. However, the studies on nitrogen and sweet corn are performed for ear yield instead of seed yield. As seeds are the main propagation method for this species, we proposed to evaluate the effects of nitrogen rates as side-dressing at different plant stages of a sweet corn seed production. Sweet corn seeds (variety BR 400) were sown in Latosol (Oxisol), and a 3×2+1 factorial scheme was designed with three nitrogen rates (40, 80, and 120 kg ha-1) at two plant stages (V6 and R1) plus the control (no nitrogen side-dressing). The evaluated variables were seed yield, protein content, P and Zn contents, germination, and vigor rates. We concluded that nitrogen applied at a rate of 120 kg ha-1 at V6 increases seed yield and maintains unaltered the protein content in seeds of sweet corn (BR 400 variety). Neither germination nor seed vigor increases when nitrogen rates are increased or administered at different stages of plant development. We also noted a slight decrease in P content or an increase in Zn content of seeds at low nitrogen rates; however, they are insufficient to promote changes in the physiological potential of sweet corn seeds.

Abstract The aim of this study was to identify resistance to bacterial halo blight in Arabica coffee lines carrying Coffea racemosa genes. Eighteen Arabica coffee lines derivative from the genotype C1195-5-6-2, and the cultivars IAPAR 59 and IPR 99 were evaluated for resistance to bacterial halo blight in two trials carried out in field conditions, in Londrina, PR, Brazil. The cultivars Mundo Novo IAC 376-4 and Catuaí Vermelho IAC 81 were included as susceptible controls. Ten lines and the cultivar IAPAR 59 showed resistance to bacterial halo blight. The cultivar IPR 99 presented intermediate reaction, and the controls were very susceptible. This is the first study to show that lines derivative from the genotype C1195-5-6-2, which has C. racemosa genes, could be a source of resistance to bacterial halo blight in coffee breeding programs.

RESUMO. Para lançamento de novas cultivares comercias de feijão é necessário a realização de uma série de experimentos denominados de ensaios de cultivo e uso (VCU). Sendo assim, a análise bayesiana utilizando informações a priori de ensaios de VCU anteriores pode ser considerada uma alternativa visando obtenção de uma maior acurácia na seleção de genótipos. Sendo assim, o presente trabalho teve como objetivos selecionar, sob perspectiva bayesiana, genótipos de feijão do tipo carioca que reúnam alta adaptabilidade e estabilidade fenotípicas, no Estado do Paraná, utilizando como informações a priori ensaios anteriores de VCU. Foram utilizados dados de seis experimentos, conduzidos em delineamento de blocos ao acaso, em que a produtividade de grãos de 18 genótipos foi avaliada. Para representar as distribuições a priori pouco informativas, utilizaram-se distribuições de probabilidade com grande variância, e para representar distribuições a priori informativas, adotou-se o conceito de meta-análises utilizando os ensaios de VCU anteriores (2007/2008, 2008/2009, 2009/2010, 2010/2011, 2011/2012, 2012/2013 e 2013/2014). A inferência bayesiana proporcionou maior acurácia na seleção dos genótipos de feijão carioca com alta adaptabilidade e estabilidade fenotípica por meio da metodologia de Eberhart e Russell. O fator Bayes indicou que o uso de informações a priori fornece resultados mais acurados na seleção dos genótipos. Com base nas prioris informativas, a maioria dos genótipos foi classificada de adaptabilidade ampla, exceto a cultivar Bola Cheia que foi classificada de adaptabilidade específica a ambientes favoráveis.

ABSTRACT. To develop new bean commercial cultivars, a series of experiments called Value for Cultivation and Use (VCU) assays are necessary. Bayesian analysis using information on prior VCU trials is an alternative to obtain greater precision during genotype selection. The objective of the present work was to select, under a Bayesian perspective, genotypes of the carioca bean from the state of Paraná that combine high adaptability and phenotypic stability, using information from previous VCU assays. This study used data from six experiments conducted in a randomized block design, in which the grain yield of 18 genotypes was assayed. To represent weakly informative prior distributions, the study used probability distributions with high variance; to represent informative prior distributions, it adopted the meta-analysis concept used in prior VCU assays (2007/2008, 2008/2009, 2009/2010, 2010/2011, 2011/2012, 2012/2013, and 2013/2014). Bayesian inference provided greater precision in selecting carioca bean genotypes with high adaptability and phenotypical stability through the Eberhart and Russell method. The Bayes factor indicated that the use of a priori information gives more accurate results for genotype selection. According to the study, most genotypes are widely adaptable based on informative priors, except for the Bola Cheia cultivar, which has specific adaptability to favorable environments.