Salinity tolerance of germinating alternative oilseeds

Integrating oilseed crops into rotations can improve soil health benefits, nutrient retention, and pollinator provisions. Field margins represent areas where incorporation of oilseeds is feasible. However in the northern Great Plains, field margins can oftentimes be areas of saline soil, which can impact seed germination and seedling establishment. Therefore, a replicated growth chamber experiment was used to determine winter camelina (Camelina sativa), 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 solution at 0, 0.2, 2, 4, 8, and 16 dS m−1 in an incubator at constant 20 °C. Fully germinated seeds were counted and removed daily for 7 days, followed by every other day for a total of 21 days. Final germination percent, corrected germination rate index, and germination velocity were calculated. Germination percent, corrected germination rate index and germination velocity were negatively affected by increases in salinity for camelina, pennycress, cuphea, and calendula. Echium germination was not impacted by salt or salinity level. Sodium based salts were more detrimental for camelina, pennycress, and calendula. Camelina and cuphea germination was tolerant to salinity, with average salinity thresholds of 8.0 and 3.1 dS m−1 and a 25% germination decline at 35.3 and 11.0 dS m−1, respectively. Pennycress and calendula germination was moderately tolerant to salinity with average salinity thresholds of 5.9 and 2.7 dS m−1 and a 25% germination decline at 9.4 and 7.7 dS m−1, respectively. These oilseeds show potential for adoption in saline soils.