Qualidade fisiológica de sementes de diferentes árvores matrizes de Corymbia citriodora (Hook.) K.D.Hill & L.A.S. Johnson

Abstract

The objective of this work was to study characteristics of seed physiological quality of different Corymbia citriodora mother trees, by following tests: accelerated aging (EA), electrical conductivity (CE), potassium content, germination and emergence in nursery. The EA test was conducted at 45°C for 72 h, evaluating the germination percentage at constant temperature (25°C) and 8 h of photoperiod. The CE and content leaching potassium (TK) were determined after imbibition of seeds in 75 ml of distilled water at 25°C for 24 h, then the seeds were submitted to germination tests. The seedling emergence test was carried out in nursery under shading net of 50% light transmission for 14 days. In germination tests were evaluated germination percentage, speed germination index, dry matter and seedling length, and in nursery, emergence percentage and speed emergence index. All experiments were conducted in a completely randomized design with 30 treatments (mother trees), with 4 replications of 100 seeds, except in tests of: accelerated aging which were used 4 replications of 25 seeds and in emergence in nursery which used 4 replications of 24 seeds. The treatments means were compared by Scott-Knott test at 5% probability. The Pearson correlation coefficients were estimated between all evaluated characteristics in different tests. The tests: accelerated aging, electrical conductivity and potassium content were efficient to evaluate the physiological seed quality and to distinguish the differences between the mother trees. The germination characteristics of seeds in laboratory presented correlation with seedling emergence in nursery.