No abstract

Weed competition limits wheat yield by reducing the availability of essential resources for its growth and development. In this sense, this study aimed to estimate the economic threshold level (ETL) of wild radish (Raphanus raphanistrum) in competition with wheat cultivars. Treatments were arranged in a factorial scheme. The factor wheat cultivar consisted of early (BRS 328), medium (BRS 177), and late (BRS Umbu) cycles and the factor wild radish population ranged from 0 to 564 plants m-2 (10 populations) for the cultivar BRS 328, 0 to 472 plants m-2 for the cultivar BRS 177 (11 populations), and 0 to 724 plants m-2 for the cultivar BRS Umbu (10 populations). The early-cycle BRS 328 presented a higher competitive ability when compared to the medium-cycle BRS 177 and late-cycle BRS Umbu. Yield losses of wheat grains due to wild radish interference can be satisfactorily estimated by the rectangular hyperbola model using the variables plant population, shoot dry matter, soil cover, and leaf area of the weed. ETL values varied as a function of the cultivar cycle, being higher for the cultivar BRS 328 (early) > BRS 177 (medium) > BRS Umbu (late). Wild radish is competitive in wheat crop, requiring at least 1.6 plants m-2 for control to be justified.

-The objective of this study was to evaluate the physiological performance of wheat seeds coated with micronutrients. The treatments were combinations of two products based on micronutrients, product "A": 780.0 g.L -1 of zinc and product "B": 182.4, 7.6 and 45.6 g.L -1 of zinc, boron and molybdenum, respectively, with five dosages of the products: 0, 1, 2, 3 and 4 mL. kg -1 seed, totaling 10 treatments with four replications. Physiological quality of the treated seed was evaluated from germination and vigor tests and the early plant growth from determinations of shoot dry weight, plant height and leaf area at 10, 20 and 30 days after emergence (DAE), as well as the rate of crop growth, relative and net assimilation. Seed yield and physiological quality were determined after harvest. It was concluded that coating wheat seeds with the product "A" , based on zinc and "B", consisting of zinc, boron and molybdenum, respectively, up to a dosage of 4 mL.kg -1 seed, did not adversely affect the physiological quality of the treated seeds or those produced. Both products tested resulted in increases in leaf area, plant height and shoot dry weight up to 30 DAE, as well as a higher seed yield.Index terms: Triticum aestivum L., early growth, physiological quality, yield.Desempenho fisiológico de sementes de trigo recobertas com micronutrientes RESUMO -Objetivou-se avaliar neste trabalho o desempenho fisiológico de sementes de trigo recobertas com micronutrientes. Os tratamentos consistiram da combinação de dois produtos a base de micronutrientes, produto "A": 780.0 g.L -1 de zinco e o produto "B": 182,4; 7,6 e 45,6 g.L -1 de zinco, boro e molibdênio, respectivamente, e cinco doses dos produtos: 0, 1, 2, 3 e 4 mL.kg -1 de semente, totalizando 10 tratamentos, com quatro repetições. A qualidade fisiológica das sementes tratadas foi avaliada por testes de germinação e vigor e o crescimento inicial das plantas foi avaliado pela massa seca da parte aérea, altura de planta e área foliar aos 10, 20 e 30 dias, após a emergência (DAE), além da taxa de crescimento da cultura, relativo e assimilatória líquida. Após a colheita avaliaram-se o rendimento e a qualidade fisiológica das sementes. Conclui-se que o recobrimento de sementes de trigo com o produto "A" (zinco) e "B" (zinco, boro e molibdênio), até a dose de 4 mL.kg -1 de semente, não prejudicam a qualidade fisiológica das sementes tratadas e produzidas. Os produtos testados promovem maior área foliar, altura de planta e massa seca da parte aérea até os 30 DAE, bem como proporcionaram maior rendimento de sementes.Termos para indexação: Triticum aestivum L., crescimento inicial, qualidade fisiológica, rendimento de sementes.

-The objective of this study was to evaluate the performance of seeds of two cultivars of lowland rice (Oryza sativa L.), coated with dolomitic limestone and aluminum silicate. It was used a completely randomized experimental design, with the treatments arranged in a 4 X 2 factorial scheme [4 treatments: dolomitic limestone; dolomitic limestone + aluminum silicate; aluminum silicate, at the dosages of 50 g/100 kg of seeds; and control (without the products) X 2 cultivars: IRGA424 and IRGA 422 CL], totaling eight treatments with four replications each. The variables analyzed were: fresh and dry weights of aerial biomass; plant height; leaf area at 10, 20, and 30 days after emergence (DAE). The physiological quality of seeds was also assessed using tests of: seed emergence; first count of germination; emergence speed index; and field emergence. It was concluded that the coating of rice seeds with dolomitic limestone and aluminum silicate does not affect seed germination and field seedling emergence. Aluminum silicate used via seed coating on cultivar IRGA 424 promoted greater leaf area, after 20 DAE. The dolomitic limestone and the aluminum silicate used via seed coating generated plants with larger dry biomass, after 20 DAE, for the cultivar IRGA 422 CL.

Seed coating is a process in which a thin and uniform polymer layer is deposited on the surface of a seed. The objective of this study was to evaluate the vigor of barley seed coated with a commercial polymer and various combinations of calcium, silicon and fungicide. In addition to a control with only the polymer coating, a total of 17 seed coating treatments were used in a completely randomized factorial design (18 treatments × 4 replicates per treatment). Calcium and silicon were applied at concentrations of 0, 25 or 50 g kg -1 of seed, and 0 or 3.0 mL of fungicide was applied. The means were compared using a Duncan test (P≤0.05). The results showed that a coating of polymer, fungicide, calcium and silicon did not affect the physiological quality of the barley seed and that the use of these products can protect the seed against pathogens without affecting the rate of emergence of the barley seedlings while ensuring good seed appearance, adhesion, distribution and coloration.

The study aimed to evaluate the influence of physiological seed quality on the spatial distribution of plants in the field, as well as the effect on variability among soybean plants. Six lots of soybean cultivar CD 202, with three vigor levels (high, medium and low) and two lots on each level were used. Lots of high physiological quality showed germination of 96% and lots considered of medium vigor showed 82% of germination and vigor between 60% and 67%, whereas lots of low vigor showed 70% germination and vigor between 55% and 58%. The test was conducted in plots formed by seven 5 m long rows with spacing of 0.45 m. The sowing was performed by opening furrows by hand with the equidistant distribution of seeds using marked rulers, corrected by the germination of each seed lot. Lots of seeds of higher vigor provide greater uniformity in the distribution of plants in the field. The reduction in seed physiological quality provides increased variability among plants within populations, throughout the entire developmental period of soybean, also affecting the seed yield per plant.

-Seed treatment with growth regulators, especially salicylic acid, is a promising alternative to the seed industry because it is an important inducer of resistance to diseases and pests, as well as acting significantly on quality and seed yield. The objective of this study was to evaluate the performance of rice seed treated with different concentrations of salicylic acid, as well as assess the crop yield and seed quality. The treatments consisted of increasing levels of 0, 50, 100, 150 and 200 mg.L -1 salicylic acid. To this was prepared a stock solution of salicylic acid and the highest concentration by successive dilution in distilled water, the other concentrations were obtained. The physiological quality of seeds produced was treated and evaluated by tests of vigor and germination, and after harvest were evaluated seed yield. It follows that treatment of rice seeds with salicylic acid concentrations up to 130 mg.L -1 at a dose of 2 mL.kg -1 seed does not affect the germination and affects the strength, however provides substantial increases in the yield of seeds. The seed treatment with salicylic acid has no influence on seed quality produced. , na dose de 2 mL.kg -1 de semente, não influencia a germinação ou afeta o vigor, entretanto proporciona incrementos substanciais no rendimento da cultura. O tratamento das sementes com ácido salicílico não apresenta influencia na qualidade das sementes produzidas.Termos para indexação: Oryza sativa L., germinação, vigor, regulador de crescimento.

-The objective of this study was to assess performance of wheat seeds after application of three components [fungicide, zinc (Zn), and polymer], separately or with their combinations, as well as assessing seed quality and yield. Thus, the treatments consisted in combinations of fungicide + zinc (Zn) + polymer, totaling six treatments, with four replicates per treatment, as follow: T0 -without application of Zn, fungicide, or polymer (control); T1 -Zn; T2 -Zn + polymer; T3 -polymer; T4 -fungicide; T5 -polymer + fungicide; and T6 -Zn + polymer + fungicide. The performance of the seeds originating from plants whose seeds had been pre-treated was assessed by tests of germination and vigor, in addition to analyzes of growth and yield. It was concluded that wheat seeds treated with zinc, fungicide and polymer are positively influenced until 30 days after emergence. The germination of wheat seeds is positively influenced by the treatment with fungicide, as much when separately applied as in combined application with zinc and polymer. The yield per plant increases when seeds are treated with Zn.Index terms: Triticum aestivum L, germination, vigor.Tratamento de sementes de trigo com zinco, fungicida e polímero: qualidade e rendimento de sementes RESUMO -O objetivo deste estudo foi avaliar o desempenho de sementes de trigo após a aplicação de três componentes [fungicida, zinco (Zn) e polímero] isoladamente, ou com a combinação destes produtos, bem como avaliar a qualidade e o rendimento das sementes produzidas. Deste modo, os tratamentos consistiram nas combinações de fungicida + Zn + polímero, totalizando seis tratamentos, com quatro repetições para cada tratamento: T0 -sem aplicação de Zn, fungicida ou polímero (testemunha); T1 -Zn; T2 -Zn + polímero; T3 -polímero; T4 -fungicida; T5-polímero + fungicida; e T6-Zn + polímero + fungicida. O desempenho das sementes produzidas, oriundas das sementes tratadas, foi avaliado por testes de vigor e germinação, além de análises de crescimento e rendimento. Pelos resultados obtidos conclui-se que sementes de trigo tratadas com Zn, fungicida e polímero são positivamente influenciadas até 30 dias após a emergência. A germinação das sementes é positivamente influenciada pelo tratamento com fungicida, tanto quando este é aplicado isoladamente quanto em aplicação combinada com Zn e polímero. O rendimento por planta aumenta quando as sementes de trigo são tratadas com Zn.Termos para indexação: Triticum aestivum, germinação, vigor.1