Effect of Plant Growth Stimulants on Yield and Yield Components of Canola

Stresses reduce plant yield and production. Growth stimulants can help increase plant yield and resistance to abiotic stresses. For this purpose, the effect of several types of plant growth stimulants on yield and yield components of rapeseed (Brassica napus L.) was studied. The experimental design was split-factorial arrangement in randomized complete block design with three replicates. The study was conducted during 2019-21 in Arak Agricultural Research Station. The main variable was planting date (September and October) and the subplots were growth stimulant treatments including amino acid, fulvic acid, seaweed extract, humic acid, their composition, and the control treatment. The results showed that the effect of growth stimulants was significant on grain yield, phosphorus concentration, number of seeds per pod, leaf area, and potassium concentration. Experimental findings showed that the use of growth stimulants in the form of seed coating and foliar spraying at the six-leaf stage and the end of the rosette can be recommended in conditions similar to this study. Soil application of humic acid was effective in germination and six-leaf stages. September planting date was more appropriate than October. Application of growth stimulants on seed yield had a positive and similar effect in September planting, but was more effective in October planting when the plants were exposed to cold stress.