Impact of Some Stress Modulators on Morphological Characteristics, Quantitative and Qualitative Traits of Quinoa (Chenopodium quinoa Willd.) Forage under Water-Deficit Stress

Quinoa (Chenopodium quinoa Willd.) is a dicotyledonous plant belonging to the family Chenopodiaceae. Protein, magnesium, fiber, potassium, iron, calcium, phosphorus, B vitamins, vitamin E and antioxidants are among the substances that are abundant in the seeds of this plant. Quinoa is one of the few edible plants that has all 9 essential amino acids in the body. Water scarcity is one of the limiting factors for crop production worldwide. Low rainfall and irregular distribution cause drought stress during the growing season of crops. Plant protection can not only increase stress tolerance, but also improve plant growth and yield. Therefore, it can be said that the proper use of this material can be considered as one of the most important management strategies in increasing the tolerance of various stresses in crops. The aim of this study was to investigate the effect of stress modulators on morphological characteristics and quantitative and qualitative traits of quinoa forage under water stress conditions.

This experiment was conducted as a pots factorial experiment based on a completely randomized design with 16 treatments and 6 replicates during 2019 at Urmia University. The first factor includes water deficit stress at four levels: 1. stress at vegetative growth stage (after plant establishment to flowering), 2. stress at vegetative growth stage (from flowering to flowering end), 3. stress at seed filling stage (From the beginning of filling to maturity), 4. no stress (control). The second factor is foliar spraying at four levels: 1. ascorbic acid (2 mM), 2. salicylic acid (2 mM), 3. nano-micronutrient chelate fertilizer (2 liters/1000 L water) and 4. Control (water spray).

The results showed that water deficit stress had a significant effect on morphological characteristics, quantitative and qualitative traits of quinoa forage. Foliar application significantly increased crude protein (CP), dry matter digestibility (DMD), fresh forage yield, stem diameter, dry weight of shoot, leaf, and flower and significantly decreased acid detergent fiber (ADF), netural detergent fiber (NDF) and crude fiber (CF) in quinoa forage. Interaction of drought stress and foliar application on all forage quality traits (except ash) was significant at 1% level. The highest amount of water-soluble carbohydrates (WSC) (23.65 percent) was obtained from water-deficit stress treatment at the stage of vegetative growth and foliar application with salicylic acid.

Irrigation is more important in the reproductive growth stages of quinoa (flowering and seed filling period) compared to the vegetative growth period. Also, to moderate the effects of water-deficit stress, improve the quantitative and qualitative yield of quinoa forage, foliar spraying with drought stress modulators is recommended.