Improving Agronomic Traits in Canola Through Foliar Applied Potassium Nitrate, Salicylic Acid and Methanol Under Water-Limiting Conditions

Abstract

ABSTRACT Water deficit is the major factor which limits the productivity of crops. The study was aimed to investigate the effects of foliar application of different chemicals and deficit irrigation on canola (Brassica napus L.). Canola F1 hybrid “Hyola 401” was sown under field conditions and grown to maturity for two consecutive years (2015–2016 and 2016–2017). The experiment was performed under rainout shelters in RCB design with four levels of irrigation water based on maximum allowable depletion: full, 90%, 80% and 70% irrigation water. Potassium nitrate (KNO3) 1%, salicylic acid (SA) 0.5 mM, methanol 20% (v/v) and water spray were foliar applied either at bud formation or pod formation stage. Results showed that net assimilation rate (NAR), crop growth rate (CGR), leaf area index (LAI), relative water content (RWC), plant height, biological yield and seed yield decreased with the reduction of irrigation water. In 2015–2016, seed yield showed a decrease of 8.4% (90% irrigation), 13.3% (80% irrigation) and 21.7% (70% irrigation) as compared to full irrigation. In 2016–2017, seed yield decreased by 6.4% (90% irrigation), 14.2% (80% irrigation) and 23.7% (70% irrigation) as compared to full irrigation water. Furthermore, SA application increased NAR, CGR, LAI, RWC, biological yield and seed yield as compared to controls. Potassium nitrate application generated similar results as SA while methanol application had limited impact. Foliar application of KNO3 and SA can improve agronomic traits and seed yield in canola under full and deficit irrigation conditions.