Foliar Boron Reduces Heat Stress-Induced Pod Abortion In Spring Canola.

Foliar boron (B) is sometimes applied to canola during early flowering in the field, but the yield benefits associated with this practice are inconsistent. Prior field research suggests that B may be most beneficial to canola under heat stress. We tested the hypothesis that foliar B application could reduce heat-induced pod abortion.  In a controlled environment experiment plants of a commercial spring canola hybrid were grown under a 20 / 15 °C day / night temperature regime continuously (control), or with exposure to a 28 / 20 °C day night treatment (heat stress) for 14 d beginning one week after first flower.  Main raceme pod counts showed that foliar B applied 4 days prior to the onset of heat stress significantly (p < 0.05) reduced pod abortion; foliar B had no effect on pod numbers in control plants.  We conclude that foliar B applications can help mitigate heat stress effects in spring canola by reducing heat-induced pod abortion.