Luana de Souza Marinke

White oats are cereals that are grown in different regions of the globe because they have good adaptability and final destination. Thus, their cultivation has shown significant increases in order to meet demand, especially for forage production, grains, and animal and human consumption. High-quality seeds are necessary for crop cultivation and white oats are sown in winter when thermal fluctuations may occur. Therefore, the objective of this study was to evaluate the physiological changes in oat seeds exposed to different temperatures during the germination phase. The experiment was a completely randomized design with four replications in a 6 × 4 factorial design. Six cultivars were evaluated: Aphrodite, Altiva, Artemis, Brava, Corona, and Guará at temperatures of 15, 20, 25, and 30 °C, and the following measurements were taken: first germination count, germination, germination speed index (IVG), and seedling length and mass. The results were analyzed using analysis of variance (F test) and the means were compared using Tukey’s test. The cultivars were physiologically affected at the minimum and maximum temperatures. At 15 °C, normal seedlings did not form, whereas the highest germination values were recorded at 20 and 25 ºC, which showed that these temperatures were the most favorable temperatures for the germination process. Vigor declined at 30 °C and there was a greater number of abnormal seedlings and dead seeds.

The search for tests that offer fast and reliable information on the physiological potential of seeds is of fundamental importance for quality control programs. The aim of this study was to evaluate the efficiency of the potassium leaching test in identification of different vigor levels of popcorn seed lots. Five seed lots of the hybrids AP8203 and AP4512 were tested for moisture content, and physiological quality was evaluated by tests of germination, first count of germination, and seedling emergence in the field. These results were compared to variations in the potassium leaching test (temperatures of 25 °C and 30 °C, volumes of 50 mL and 75 mL of water, fifty and one hundred seeds, and periods of 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 4 h and 5 h). Results showed that the potassium leaching test is efficient in separating the popcorn seed lots regarding physiological potential, and the most adequate conditions for this test are the use of fifty seeds with 50 mL of water for two hours at 30 ºC.

Electrical conductivity of coffee seeds in function of the number of seeds and imbibing period / Condutividade elétrica de sementes de café em função do número de sementes e período de embebição

Vigor of lentil seeds evaluated by the tests of accelerated aging and controlled deterioration / Vigor de sementes de lentilha avaliadas pelos testes de envelhecimento acelerado e deterioração controlada