Geographic variation in natural rubber yields in natural populations of Helianthus annuus (Asteraceae, Sunflowers)

摘要

Populations of Helianthus annuus, ranging from eastern Oklahoma to coastal southern California, weresampled and the yields of natural rubber (NR) from leaves determined by Accelerated Solvent Extraction(ASE). The highest yielding populations were Mill Creek, UT with a yield of 20.8 mg/ g and in theWaco, TX area with 14-18.2 mg/ g leaf DW. The lowest yields were in Preston, ID (1 mg/g), Redmond,OR (2 mg /g), Eagle Lake, NM (2.7 g/ mg), Post, TX (3 mg/g) and Quanah, TX (3 mg/ g). The highestyielding individuals were found in Mill Creek, UT (42 mg /g) and McLennan Co., Waco, TX (31 mg/ g).The appears to be no geographical relationship to the rubber yields. The highest yielding populations arein very different eco-systems with different soils, climates and ecologies. Adjacent populations are oftenquite different in the concentration of rubber. The most variable populations were San Diego, CA (0 - 16mg/ g), Logan, UT - Preston, ID (0 - 12 mg/g), Dodge City, KS (0, 0, 7,8,10 mg/ g), and Meade, KS (2, 2,4, 18 mg/ g). There is some geographic trends in rubber variation in central Kansas. But, other highlyvariable populations are isolated in different ecosystems. Additional studies needed to more fullyunderstand the variation. Published on-line www.phytologia.org Phytologia 100(1): 62-70 (Mar 16,2018). ISSN 030319430.