Lesquerella seed pretreatment, seed preconditioning on emergence at various planting depths and seed production

Lesquerella fendleri (Gray) Wats. is a potential new oilseed crop for the arid southwestern United States. In the first study presoaking the seed in an aqueous solution of 100 mg GA3 l-1 H2O followed by complete drying improved germination in light and appeared to satisfy light requirement when treated seed were germinated in the dark. Soaking seed in water alone appeared to satisfy the light requirement under dark conditions suggesting that presoaking in water alone was sufficient to leach out or deactivate the light requiring dormancy factor.; In the second study we determine the effect of a number of seed treatments on the germination and emergence of Lesquerella over a wide range of planting depths in field soil under greenhouse conditions. Among the three seed lots evaluated, 90--91 MAC and 92--93 MAC seed lots had consistently higher germination than the 91--92 MAC seed lot. Among the five planting depths there were no significant differences between responses at 5 and 10 mm planting depths. Soaking seed for 4 hours in 100 mg GA 3 l-1 + 2 g KNO3 l-1 in water or 100 mg GA3 l-1 in water resulted in the highest emergence. Soaking seed in water alone also had a beneficial effect.; The third study was to identify the most critical stage or stages for moisture deficit and to determine the effect of moisture deficit on yield, yield components, oil and fatty acid composition. The amount of water applied ranged from 810 to 729 mm in year 1 and 810 to 625 mm in year 2 of the field study. Seed weight per plant and number of pods per plant were generally higher when water availability was maintained at or above 50% AWC throughout the growing season. Lesquerella was more sensitive to water availability during flowering and seed development as there was a greater loss in seed yield when irrigation was delayed to 25% AWC during that stage of development. Results of the field study and greenhouse study were similar. Seed yield and dry matter production from the 2 year field study were closely related to the seasonal cumulative evapotranspiration.