Foliar application of micronutrients and salicylic acid to improve some quality traits and yield of canola (Brassica napus L.) under water deficit stress.

canola (Brassica napus L.) is one of the most important oilseed plants that has been ranked third in the oil production after soybeans and oil palm. Drought is seriously the most important factor limiting the growth and production of canola in Iran. By foliar application of micronutrients, plant growth condition can be improved under stress. Salicylic acid (SA) plays an important role in abiotic stress tolerance, and more interests have been focused on SA due to its ability to induce a protective effect on plants under adverse environmental conditions. It is necessary to know the traits related to drought tolerance and their relationship with Seed yield. Due to the important role of roots in the absorption and conduction of water and nutrients, accurate knowledge of the root system and how it is distributed in the soil is of particular importance. therefore, the purpose of the present study was to investigate the Effect of foliar application of micronutrients and salicylic acid to improve some quality traits and yield of canola (Brassica napus L.) under water deficit stress.

the experiment was conducted as split factorial in a randomized complete block design with three replications at Lorestan University College of Agriculture, Iran during 2017-2018. Water deficit was considered as the main factor in levels irrigation at 80 (control) and 30% of field capacity, and in the subplots subtractive treatment of the two factors of foliar application of micronutrient elements (non-consumption and spraying at a concentration of 0.2%) and salicylic acid concentration of 0, 0.5, 1 and 1.5 mM). The time of water deficit stress coincided with the stage of the beginning of regrowth (BBCH32). foliar application of micronutrient fertilizer in rosette stage (BBCH29) and foliar application of salicylic acid in two stage of flowering beginning (BBCH60) and pod filling (BBCH72). the measured traits included Chlorophyll Total, Carotenoids, Photosynthesis rate, Transpiration rate, seed yield, oil percentage, and Protein percentage. the data was analyzed by statistical analysis system (SAS version: 9.1). the means were analyzed using the Duncan test at P=0.05.

The results of analysis of variance showed that the triple interaction of stress in micronutrient fertilizer and salicylic acid on all traits studied in this experiment were significant.The results of comparing the mean of the data showed that water deficit stress significantly reduced total chlorophyll (14%), carotenoids (21%), photosynthesis rate (19%), transpiration rate (53%), grain yield (27%), oil percentage (11%) and significantly increased protein content Seeds (22%). the combination (no stress + 1.5 mM salicylic acid spraying and concentration of 2 per thousand fertilizers Micronutrients) was obtained. produced the highest total chlorophyll (2.23 mg g-1 wet weight), transpiration rate (3.12 mmol H2O2 m-2 s-1), seed yield (4955.7 kg ha-1) and oil percentage (45.7). foliar application of micronutrient fertilizer and 1.5 mM of salicylic acid significantly increased total chlorophyll (34%), carotenoids (29%), photosynthesis rate (27%) and Seed yield (36%) compared to the control treatment (without application of micronutrient fertilizer and Salicylic acid).

A triple micronutrient fertilizer (iron+zinc+ manganese) with a concentration of 0.2% is recommended along with a concentration of 1.5 mM of salicylic acid to reduce the negative effects of water deficit stress and achieving acceptable seed yield.