Outplanting performance of three provenances of Quillaja saponaria Mol. established in a mediterranean drought-prone site and grown in different container size

Abstract

In degraded environments with restricted seed availability, like those burned by wildfires in central Chile during 2017, the use of plant material from outside its area of origin for restoration purposes needs to be accurately investigated. We assessed the early development of three Chilean provenances of Quillaja saponaria grown in different container sizes (140 vs. 280 mL) in the nursery and then outplanted in a common field trial at a site severely affected by fire under Mediterranean-type climate. We analyzed growth, biomass, and leaf-level physiological traits. In the nursery, there was a significant provenance by container type interaction for the biomass traits (P < 0.05). Seedlings from the Maule provenance cultivated in larger containers had the highest biomass, while the lowest biomass was observed for the Metropolitan provenance cultivated in small containers. Two years after outplanting, the provenance by container size interaction was significant for stomatal conductance and chlorophyll density. Seedlings from the Metropolitan provenance cultivated in larger containers exhibited a higher stomatal conductance, while those from the Maule provenance cultivated in small containers exhibited the highest chlorophyll density. Seedling height showed significant variation for provenance and container size. The tallest seedlings were those grown in larger containers from the Maule provenance; however, no differences in survival and height increment were found. Gas exchange parameters differed among provenances, the Metropolitan provenance had a low performance and the opposite was found for the Biobio and Maule provenances. This study demonstrated that different provenances of Q. saponaria have stable performances in a Mediterranean site, which support their use for restoration purposes outside their home area with no detrimental effects on outplanting performance.