ABSTRACT:In a quality control program, seed vigor evaluation is of fundamental importance for the success of the program. The objective of this project was to evaluate the efficiency of several vigor tests to evaluate the physiological quality of Brachiaria brizantha cv. 'BRS Piatã' seed lots and to preview seedling emergence in the field. Ten grass seed lots of the B. brizantha cv. 'BRS Piatã' were evaluated by the following tests: germination, first count of germination, accelerated aging (43 °C/48 hours), cold test (seeds rolled in paper towel), seed water content before and after accelerated aging, electrical conductivity (50 and 75 mL, 25 °C and readings made 2, 4, 6, 8, and 24 hours after beginning the test), speed of germination index, and seedling emergence in sand substratum in the laboratory (26 ± 3 °C) and daily seedling counts between the 7th and the 21th day after sowing. The treatment replications were distributed in the laboratory according to a completely random design with four replications. Seedling emergence in the field data were analyzed according to a randomized complete block design. Treatment means were compared by the Scott Knott test, at the 5% level of probability. The tests for germination and first germination count, seedling emergence and first emergence count in the sand, and accelerated aging are useful to assess the vigor of seed batches of the piatã grass, and provide similar evidence to the seedling emergence in the field.

Alibertia edulis Rich. is a native species of the Brazilian Cerrado and can be used for reforestation of degraded areas. In addition, it produces edible fruits. The objective of this study was to evaluate the effect of substrates and water levels on the emergence, initial growth, and quality of seedling of A. edulis. The substrates tested were: latosol (L), latosol + sand (L + S = 1:1), latosol + sand + chicken manure (L + S1 + CM = 1:1:0,5), latosol + sand + chicken manure (L + S2 + CM = 1:2:0,5), and latosol + commercial substrate (L + C = 1:1); and the water retention capacities (WRC) tested were: 25, 50, 75, and 100%. The experiment was carried through in a completely randomized design and subdivided into a plot scheme, in which the plots represented water availability and the subplots represented the substrates. Latosol + commercial substrate at 100% of WRC provided the best conditions for emergence, initial growth and formation of seedlings of A. edulis. Sowing in the substrate Dystroferric Red Latosol isolated at 25% of WRC should not be used for the formation of seedlings of this species.

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Plukenetia volubilis is a species native to the Amazonia and has economic potential due to the high contents of polyunsaturated fatty acids and vitamins of the seeds; however, information about production of seedlings in nursery is scarce. Factors that contribute to fast emergence and generation of vigorous seedlings are desirable for plant production in the nursery. Therefore, this study aimed to identify the most favorable substrate and seed position for the production of P. volubilis seedlings. The seeds were sown in the following four positions: hilum facing up, hilum facing down, seed lying on its cotyledon suture, and seed lying flat on one of its cotyledon faces. The substrates were sand, vermiculite and commercial substrate. Treatments were distributed according to a completely randomized design in a 4 × 3 factorial arrangement (seed position and substrate) with three replicates of 25 seeds each. The following variables were evaluated: emergence percentage; first count of seedlings; number, width and length of leaves; plant height; stem diameter; dry matter of shoots and roots. It was concluded that the production of P. volubilis seedlings is not affected by either substrate or seed position at sowing. The substrates most favorable to the quality of P. volubilis seedlings were the commercial substrate and vermiculite, always for the positions of seed lying on its cotyledon suture, with faces parallel to tube walls, and seed lying flat on one of its faces.