Soil Salinity: Germination Tolerance of Alternative Oilseed Crops for Soil Health.

World-wide, saline soils contribute to over US$27.3 billion in agricultural losses annually by reducing plant growth through osmotic imbalances and ion toxicity. Nearly 800,000 ha of salt affected land is located in the northern Great Plains. Limited information is available on the germination of alternative oilseed crops adapted to this region. Therefore, a growth chamber experiment was used to determine winter camelina (Camelina sativa L. Crantz), winter pennycress (Thlaspi arvense L.), echium (Echium plantogineum), cuphea (Cuphea viscosissima X Cuphea lanceolata), and calendula (Calendula officinalis) tolerance to germinating under saline conditions. A total of 50 seeds, replicated 3 times were germinated in petri dishes saturated with NaCl, CaCl, and Na₂SO₄ solutions to give a range of dS m^-1 of 0 to 16 in an incubator set at 20 °C. Germinated seeds were counted and removed daily for 7 days, followed by every other day for a total of 21 days. The experiment was repeated twice. Final germination percent, corrected germination rate index, and germination velocity were calculated. Increases in salinity, regardless of salt type decreased the final germination, corrected germination rate index, and germination velocity for camelina, pennycress, cuphea, and calendula. Pennycress and calendula were more negatively affected by Na salts. Echium germination was not affected by salinity, but dormancy of this species may mask the effects. Germination of camelina and cuphea were tolerant to salinity with a threshold of 5.6 and 3.4 dS m^-1 and a 25% germination decline at 25 and 12 dS m^-1, respectively. Pennycress and calendula germination was moderately tolerant to salinity with a germination threshold of 5.2 and 3.2 dS m^-1 and a 25% germination decline at 10.6 and 8.7 dS m^-1, respectively. These oilseeds show potential for adoption in saline soil and to provide additional revenue stream for producers affected by salinity.