Foliar applied potassium stimulate drought tolerance in canola under water deficit conditions

Drought is a burning issue all over the world that has led to remarkable reductions in the growth and yield of crops. Based upon the current problem, a series of two rain out shelter pot research experiments were performed to evaluate the drought tolerance in canola by foliar application of potassium (K) under water deficiency conditions in the Department of Agronomy, University of Agriculture Faisalabad, Pakistan. Four varieties of canola (Faisal Canola, Cyclone, Shiarlae, and Dunkled) were tested under two water deficit levels (100% FC and 50% FC) and two treatments of foliar potassium application i.e., 0% K and 2% K. The data was recorded with standard procedures when the plants were grown up to maturity. Results concluded that drought posed a significant decrease in all parameters under study. However, supplemental foliar application of potassium at the rate of 2% at both (vegetative and reproductive) stages of canola enhanced the water potential (0.24% and 0.23%), osmotic potential (0.12% and 0.11%), turgor pressure (0.66% and 0.58%), respectively. Similarly, the chlorophyll contents as chlorophyll a (0.25% and 0.28%), chlorophyll b (1.26% and 1.80%) and leaf carotenoid contents (0.20% and 0.62%) were also increased where K was applied at the rate of 2% during vegetative and reproductive stages of canola. The foliar applied K at the rate 2% enhanced leaf photosynthetic rate (13.11 mu mol CO2 m(-2 )s(-1) and 15.96 mu mol CO2 m(-2 )s(-1)), transpiration rate (5.36 mu mol CO2 m(-2 )s(-1) and 5.54 mu mol CO2 m(-2 )s(-1)) and stomatal conductance (0.22 mu mol CO2 m(-2 )s(-1) and 0.26 mu mol CO2 m(-2 )s(-1)) of the plants at both stages. Yield attributes such as thousand seed weight (1.03% and 1.03%), seed yield (0.58% and 0.58%) and biological yield (0.35% and 0.38%) were increased by foliar K application under water deficit conditions at both stages. The genotype Shiralae showed significant improvement among all others genotypes under normal as well as water deficit conditions