SALT AND WATER-STRESS EFFECTS ON GERMINATION OF GUAYULE SEEDS

The test materials included 4 USDA selections (11646, 11604, 11633 and A48118) and 1 cultivar (593). Petri dish solution cultures were used for evaluating salt effects, and 2 sandy soils (Typic Torrifluvents and Typic Torripsamments) placed in petri dishes were used for studying soil water stress effects. Seed germination may be reduced by approximately 25%, due to salinity of salt solutions ranging 7-19 mmho/cm with a descending order of tolerance of 11646, 593, 11604 = 11633, and A48118. Selection 11646 showed excellent characteristics as well as high salt tolerance. Specific ion effects were insignificant when tested in salt solutions having mixed ion compositions. Soil water stress needs to be controlled at less than about 0.8 bar if germination is to be accomplished without adverse effect of water stress.