Variabilidade genética para emergência de sementes e crescimento de plantulas de bacabi (Oenocarpus mapora Karsten) e bacaba (Oenocarpus distichus Mart.)

Abstract

This work had as objective to study the variability and the genetic gain waited through selection between progenies of open polinization bacabi ( Oenocarpus mapora Karsten) and bacaba (Oenocarpus distichus Mart.) for the characters of emergency and initial growth of the changes. For such goal, were collected mature fruits of each matrix in the differents areas: of natural occurrence, producers yards and from the Germoplasm Bank of the Embrapa Amazônia Oriental in Belém. The fruits were unpulped manually after two days they were immersed in water, and immediately sown in tubetes I contend composed substrate of soil, excrement of birds and residue of dendê in the same quantities. It was used completely randomized blocks experimental design with 47 treatments (progenies), four replications and parcels with 24 seeds. The variances analyzed were: the emergency percentage (PE), the average time of emergency (TME), the rate of absolute growth of the height of seedling (TCAA) and rate of absolute growth of the diameter of seedling (TCAD). The progenies showed significant statistic differences (p<0,01) for all the analyzed characters of bacabi/bacaba and for the alone two species, with excellent experimental precision. The estimatives of the genetics and environmentals variances, and herdability showed that the highest part of the variation among the progenies was due to the additive effects. The same tendency showed in the herdability, was confirmed to rate "b" with magnitudes expressing highest genetic variability to the same characters. The gains of selection available take off the percentages of the pre-determined selection showed values highest to ability and rate time of emergency of seeds and initial growth of seedling in all characters, were auspicious for the pression of the selection with intensity of the 10% to progenies bacabi/bacaba and alone bacabi and 20% to progenies of the bacaba.