Establishment of a clonal bank of <i>Caesalpinia spinosa</i> (Mol.) O. Kuntz by selection of plus trees and grafting

Abstract

In Ecuador, plant propagation techniques are not available commercially to establish clonal banks of Caesalpinia spinosa (Mol.) O. Kuntz (guarango) plus trees, which limits the development of in vitro propagation protocols of this specie. The objective of the present work was to establish a clonal bank of C. spinosa by selecting plus trees and grafting. Guarango trees belonging to the province of Chimborazo, Guano canton were selected based on total height, height at the beginning of the crown, height of crown, crown surface, crown symmetry, flowering, fruit production and content of tannins in the pod. The patron plants to make the grafts were obtained from scarified seeds, soaked for 48 hours at room temperature and planted in beds of 1.0 x 3.0 m. At 40 days, the seedlings were transplanted into pockets and at 16 months the grafts were made in the patron plants. Three types of graft were used (simple slit in the patron, single slit in the spike and bud grafting). For each, 100 patron were used. Of the eight trees plus collected in the field, the ecotype CHSt03 was used to make the grafts. It was showed the highest total height (6.6m), height at the beginning of the cup (2.2m), cup surface (> 70%), cup volume (> 10%), cup symmetry (1), fruit (40kg / tree) and total polyphenol content in pods (5870 μgEAGgMS-1). The graft by simple slit in the patron had the highest stuck percentage (80%). These results allowed to establish a clonal bank of 80 plants grafted of C. spinosa of the ecotype CHSt03, which establish the bases to develop protocols for in vitro propagation of this forest species, native of Ecuador. Keywords: biodiversity, biotechnology, forestry, industry, tannins