干旱区生态环境知识资源中心

Preliminary studies have shown that Grindelia chiloensis has higher resin contents than Grindelia camporum which has been previously evaluated as a new resin crop for arid environments. G. chiloensis may provide an additional source of germplasm variability from which to improve resin content and adaptation to cold, arid environments.

A number of studies were conducted to evaluate several native populations of G. chiloensis growing in its native environment in southern Argentina. Three native stands of G. chiloensis from northeastern Patagonia were evaluated. All three sites are located around 42 S latitude, within 200 m from the seacoast, and receive an average precipitation below 160 mm/year. Native cover of G. chiloensis ranged between 8% and 11% and was not significantly different among populations. Average individual plant net primary productivity (NPP) was estimated with a single harvest at the end of the growing season (April 1995) and ranged between 92 g and 168 g dry weight (DW). No significant difference in NPP was found among populations. Plant density was significantly different among populations (P < 0.01) and ranged between 2.8 and 0.16 plants/m(2).

Crude resin (CR) content of the year's biomass (stems, leaves, and flowers) was significantly different among populations (P < 0.01); CR content was 23.4%, 17.4%, and 16.7% for the three populations studied. Refined resin (RR, an estimate of resin acids content) was significantly different among populations and ranged between 16.3% and 11.5% for these samples. The ratio RR/CR was around 69% and was not different among populations. Capitula and leaves did not differ in resin CR and RR contents, but these were significantly higher than those found in stems. This contrasts with what has been found in G. camporum in which capitula have significantly higher resin contents than leaves. This characteristic will influence the ideotype used in the selection of high productivity germplasm.