GENETIC PARAMETERS IN SEED CHARACTERS OF Ormosia discolor UNDER DIFFERENT AMBIENT CONDITIONS

Abstract

Ormosia discolor Spruce ex Benth. is a native tree of the Amazon with has fast growth and nodulation capacity, whose seeds are used for craftwork. The objective of this study was to estimate genetic parameters in seed characters of O. discolor at different ambient temperatures and to indicate superior matrices to compose seed lots. Seeds of 20 progenies selected from a population in the state of Amazonas were collected. Three experiments were performed under different ambient temperatures at the Seed Center laboratory/UFAM. Experiment 1 was performed at constant temperature of 30 °C. In experiment 2, seeds were submitted to a temperature of 35 °C. In experiment 3, after five months of freezing, the seeds were submitted to a temperature of 30 °C. The experimental design was completely randomized, consisting of 20 progenies, four replicates, and 25 seeds per plot. The germination characters evaluated were germination rate, mean germination time, and synchronization and speed germination indexes. Genetic and phenotypic variances and correlations, broad-sense heritability, and genetic gain through direct selection were estimated. O.discolor progenies showed significant genetic variability for most of the characters evaluated. High heritability and accuracy values (> 90%) were found for germination rates at all ambient temperatures. Matrices 2, 7, and 16 were superior for germination characters at all temperatures tested, being indicated for seedling production. Eighteen O. discolor seeds are sufficient for biometric analysis with accuracy of 95% in genotype selection.