Coffee seeds are classified as intermediate because they have low tolerance to desiccation and low longevity. Consequently, moisture control and storage conditions are important factors in maintaining the physiological quality of these seeds. Thus, the objective in this work was to evaluate the water content effect on coffee seed longevity. Seeds of five Coffea arabica cultivars from the 2016/2017 crop were used. Part of the harvested seeds was dried in the shade until reach 12% moisture and the other part did not go through drying process, remaining with 40% water content. The seeds were stored in a cold chamber at 10 ºC for a period of nine months, and the physiological quality was evaluated every three months by germination, root protrusion, seedlings with expanded cotyledonary leaves, seedling dry mass and enzymatic analysis of catalase enzymes and superoxide dismutase. Regardless of the cultivar, wet seeds coffee storage provides better maintenance of physiological quality for up to nine months. Seedling vigor is reduced throughout the storage period, regardless of seed water content.

Seed quality is extremely important for agribusiness, as it can affect the stand establishment, as well as the competitive ability of the plant, affecting its yield potential. The aim of the present work was to evaluate the initial development and the production performance of the maize crop as a function of the vigor of the seed lots. The experiment consisted of 10 treatments, involving two factors: two stands (ideal number of plants and ideal number of seeds corrected by the seedling emergence test in bed); and five seed lots as a function of vigor (63, 68, 83, 87 and 99% vigor), according to the results of the cold test. The experimental design was a randomized block design, with four replications. The following parameters were determined along the crop cycle: plant height; chlorophyll and plant cover index; cycle; initial and final populations; and components of grain yield. The use of high-vigor maize seeds favors the initial development of the crop and soil cover, with a positive influence on the number of grains per ear and final population of plants in pre-harvest, in addition to reducing the cycle. High-vigor maize seeds promote gains in yield; for each increase of 1.0 percentage point in the level of seed vigor of the lot, estimated by cold test, the increase in grain production can reach 43.5 kg.ha-1.

Tratamento com ácido ascórbico na qualidade fisiológica de sementes de milho envelhecidas artificialmente Treatment with ascorbic acid on the physiological quality of artificially aged corn seeds

Seed treatment is an important procedure in soybean cultivation and is currently performed in two ways: industrial seed treatment (IST), performed by the seed companies industry, and OnFarm treatment, performedby the producer. The objective of this research was to compare the influence of industrial and OnFarm soybean seed treatment technologies, including the machines and processes, on the occurrence of mechanical damage and the functional quality of treatment. Soybean seeds were subjected to phytosanitary treatments with different processes and machines: (1) industrial treatment with a batch process; (2) industrial treatment with a continuous flow process, (3) OnFarm continuous flow treatment with dosage distribution via fixed-volume doser and seed mixing via worm screw; and (4) controlrepresented by untreated seeds. The occurrence of mechanical damage was evaluated by the sodium hypochlorite test. The functional quality of the treatments was analyzed by seed coating, determined by means of digital image processing; particle detachment (dust-off); and dose effectiveness of thiamethoxam, determined by high-performance liquid chromatography (HPLC). The treatment of soybean seeds in batch or continuous flow industrial systems ensures better seed coating, greater dose effectiveness, less particle detachment and a lower occurrence of mechanical damage compared to OnFarm application technology. The digital processing of high-resolution images is efficient for quantifying the coating of soybean seeds by phytosanitary products. Seed coating is directly related to dose effectiveness.

The physiological priming has been used to standardize and increase the speed of development of seed lots. The use of this technique is essential in coffee cultivation, as the crop has low longevity associated with slow and uneven germination. The objective was to evaluate the effect of physiological priming on the physiological quality of coffee seeds stored with different water contents. Seeds of two cultivars of Coffea arabica were used: cv. Catuaí Vermelho IAC144 and Topázio MG1190. A portion of the seeds were dried in the shade until reaching 12% moisture, and the other did not undergo drying. The seeds were stored in a cold chamber at 10 °C for nine months. Every three months, the physiological priming technique was performed with subsequent evaluation of the physiological quality by germination tests, root protrusion, normal seedlings at fifteen days, strong normal seedlings, seedlings with expanded cotyledonary leaves and seedling dry weight. Seeds that did not undergo drying subjected to the physiological priming technique maintained physiological quality after nine months of storage. Physiological priming was detrimental to dry seeds stored for nine months.