Natural resources conservation: guava and other Myrtaceae germplasm ex situ conservation in Merida, Venezuela.

摘要

In this report we deal with the germplasm collection of guava plants and other Myrtaceae, grown in a suburban environment of Merida, Venezuela. This ex situ bank of germplasm was established from seeds and it is the first in Venezuela. Its existence will allow the detection of genes of interest that might contribute to the genetic improvement of the species. The samples of "wild" guavas and other Myrtaceae were collected in different areas of the country (other Myrtaceae mainly south to the Orinoco River). Currently, the collection comprises 159 samples, of which 101 samples are P. guajava and 58 samples are other species of Myrtaceae. Of the latter, at least 20 samples have already been identified. This collection includes herbarium vouchers, seeds, DNA samples, and information concerning the origin of the trees. The seeds were aseptically germinated and acclimated in a greenhouse before transfer to the field. The ex situ collection comprises 50 different samples of P. guajava and 4 samples of other Myrtaceae. Presently, the plants are approximately two years old and in transition to the reproductive stage. The plants established in the field were used to extract nucleic acids for the DNA collection. The phenotypic traits were evaluated and compared with those of the donor plants. Some of the plants exhibit a promising phenotype and were cultivated in vitro, using apical and axial meristems as well as nodal segments as the starting material.