Evaluation of pre-germination treatments in Prosopis caldenia seeds

Prosopis caldenia is a woody perennial species endemic to the temperate semi-arid phytogeographic region of central Argentina known as the Calden district. Currently, some areas of this region are degraded because of livestock, fires, the advance of the agricultural frontier, and lack of forest management, among others. To improve the restoration of this important species within its natural distribution area and/or for the expansion of the wooded area, propagation methods must be developed that produce acceptable numbers of seedlings when seeds are put in conditions to germinate. The seeds of P. caldenia present an impermeable coat that prevents uniform imbibition. The literature is scarce regarding the study of scarification methods in this species. The objective of this work was to evaluate which pre-germination method (mechanical, chemical, or thermal) best adapts and improves the germination parameters. The seeds were placed in a germination chamber at a temperature of 30 degrees C for 12 days and daily observations of germination, non-embedded seeds, non-germinated embedded seeds, root length, and germination indices were carried out. The results indicate that mechanical scarifying achieves the highest germination rate, germination indices, and root length (P < 0.05) followed by acid treatment. This research should be repeated in the nursery to verify whether the laboratory results are maintained under plant production conditions.