The role of foliar application of plant-derived smoke on yield and growth characteristics of wheat (Triticum aestivumL.)

Food security concerns have necessitated the increase in agricultural production due to the ever-increasing world population, projected to exceed 9.6 billion people by 2050. It has been reported that various physicochemical contents of plants are increased by the solution of plant smoke. The biologically active compounds of smoke are soluble in water and in very low concentrations, they cause significant physiological responses in plants. These compounds can be used in the form of aqueous extract under the name of water smoke, by designing a device based on previous research in this field. Through various studies, it has been reported that the smoke enhancing activity is due to the presence of karrikin compounds (KARs).

This research was carried out in a factorial experiment in base of randomized complete block design (RCBD) in three replications in the research farm of the Campus of Agriculture and Natural Resources, Razi University, in the crop years 2019-2020 and 2020-2021. The factors included irrigated wheat cultivars (Mihan and Sirvan) and foliar application with a concentration of one liter per hectare in the phenological growth stages of wheat at eleven levels including no application (control), application in the stages of double ridge, second node detectable, ear emergence, anthesis, double ridge + second node detectable, double ridge + ear emergence, double ridge + anthesis, second node detectable + ear emergence, second node detectable + anthesis, ear emergence + anthesis. The studied traits in this research include seed yield, biological yield, harvest index, seed per spike, 1000-seed weight, seed filling duration and seed filling speed.

The results of this study showed that the maximum seed filling speed in foliar application at the stage of second node detectable was average (1.38 mg. day-1) in both Mihan and Sirvan cultivars, and the maximum weight of 1000-seed weight (48.93 g) in Mihan cultivar in foliar application at the stage of ear emergence was obtained, also foliar application in the stage of double ridge + second node detectable had the highest harvest index with average (45.79%) and seed filling duration with average (48.51 days) All of which were in the Mihan cultivar. Foliar application in the stages of double ridge + second node detectable and anthesis caused the highest seed yield with average (6.02 t. ha-1). The maximum number of seeds per spike with average (55.83) and biological yield with average (15.61 t. ha-1) was related to foliar application at the stage of double ridge + ear emergence in Mihan cultivar.

Smoke water has the necessary potential to increase the quantity of wheat. If the results of this research are confirmed in other researches, it can be recommended to use water smoke as a practical and low-cost technology, especially for poor farmers in developing countries.