24-Epibrasinolid and Cauliflower (Brassica oleracea var. botrytis) Extract Effect on Grain Yield and Some Morphophysiologycal Characteristics of the Sensitive and Tolerant Quinoa (Chenopodium quinoa Willd.) Cultivars

Introduction Recent alterations in climate patterns have resulted in a reduction of precipitation. This shift not only contributes to drought conditions but also increases the salinity levels of both water and soil utilized for agricultural purposes. To mitigate the impact of this phenomenon on food security, it is essential to consider strategies that involve the utilization of alternative plants and compounds, such as Brassinosteroids (BRs), which can enhance the resilience of plant products to salinity stress. Quinoa (Chenopodium quinoa Willd.) is a plant with high production potential, which can be used as a good candidate to replace salt-sensitive cereal due to its richness in nutrients needed by humans and livestock. Due to the consecutive droughts in the Iran and as a result the lack of water resources and then the salinity of water and soil resources, the production of some traditional agricultural and horticultural plants has faced many limitations. This has caused a decrease in the quantity and quality of agricultural products in these regions. In the meantime, the drying up of Lake Urmia, which was considered the largest salt lake in the world, has faced additional tension in West Azerbaijan province. For this reason, the introduction of planting pattern of new plants with high yield potential, which have good agricultural performance in dry and salty conditions, and the production product, is of high quality is on the agenda. Materials and Methods In order to investigate the effect of 24-epibrassinolide and cauliflower (Brassica oleracea var. botrytis) extract on some biochemical characteristics and related to the forage quality of Quinoa cultivars at salinity levels, a factorial experiment in the form of a completely randomized design (CRD) with four replications in the greenhouse of the Faculty of Agriculture of Azad University of Mahabad in the spring and summer of the year 1401 was done. The investigated factors included the tolerant (Titikaka) and semi-sensitive (Sajma) Quinoa cultivars to salinity, the use of stress-modulating substances (at three levels, without application, application of 24-epibrasinolide and application of cauliflower extract), and the salinity levels (2 levels, without salinity and 15 dS m-1) of irrigation water. After sampling, morphological, biochemical and fodder quality characteristics were measured. Results and Discussion The results showed that spraying with 24-epibrassinolide and cauliflower extract increased total chlorophyll, carotenoid, relative content of leaf water, proline, phenol, soluble carbohydrates, and forage quality characteristics (digestible dry matter, crude protein, ash, water-soluble carbohydrates), and decreased hydrogen peroxide (H2O2) and negative attributes associated with forage quality (insoluble fibers in acid detergent, insoluble fiber in neutral detergent and fiber). The use of two anti-stress solutions, especially 24-epibrassinolide, significantly improved oxidative damage caused by salinity stress by reducing hydrogen peroxide and increasing the activity of non-enzymatic antioxidants. Conclusion In this study, morphological characteristics (root length, plant height and dry weights of roots, shoots and seeds), total chlorophyll, carotenoid, relative content of leaf water and digestible dry matter of forage decreased under salt stress. While the amount of proline, phenol, soluble carbohydrates, hydrogen peroxide and characteristics related to forage quality (crude protein, insoluble fibers in acidic detergent, insoluble fibers in neutral detergent, percentage of ash, water-soluble carbohydrates and crude fiber) increased. Foliar application of 24-epibrassinolide and cauliflower extract enhanced morphological traits, total chlorophyll, carotenoids, relative leaf water content, proline, phenols, and leaf soluble carbohydrates. It also improved forage quality by increasing the percentage of digestible dry matter, crude protein, ash content, and water-soluble carbohydrates, while reducing hydrogen peroxide levels and undesirable forage quality traits such as acid detergent fiber (ADF), neutral detergent fiber (NDF), and overall fiber content. According to the results, the use of two anti-stress solutions, especially 24-epibrasinolide, significantly improved the oxidative damage caused by salt stress by reducing hydrogen peroxide and increasing the activity of non-enzymatic antioxidants. Titikaka was more resistant to the negative effects of salinity stress on morphological and biochemical characteristics than Sajma, and Sajma under foliar spraying of cauliflower extract and Titikaka under foliar spraying of 24-epibrassinolide showed a better response to saline conditions. Therefore, in order to improve the growth and quality of fodder and reduce the negative effects of salinity stress, foliar spraying with 24-epibrassinolide and cauliflower extract can be recommended in both Titikaka and Sajma cultivars. .