Exploring potential of quinoa as a forage crop in dryland farming: effects of plant growth regulators and application timing

Abstract

Traditionally cultivated for its seeds, quinoa (Chenopodium quinoa L. Willd) is increasingly being explored as a dual-purpose (grain and forage) or forage crop in integrated crop–livestock systems, particularly on marginal soils. This study investigated the effects of plant growth regulators and their application timing on drought tolerance, herbage yield, and the nutritive value of quinoa under rainfed conditions in Türkiye over 2 years. The treatments involved the application of the plant growth regulators zeatin, brassinolide, and their combination. These were applied either as pre-sowing seed treatments, post-sowing foliar applications, or both. A control group with no growth regulator was included for comparison. The herbage yield of quinoa without growth regulator application ranged from 3.19 to 4.67 t dry matter ha⁻¹. The application of growth regulators significantly influenced agronomic and physiological parameters, reducing the time required for plants to reach maturity. Combined pre- and post-sowing applications resulted in taller plants, larger root diameters, and increased herbage yield compared to control plants. The growth regulator applications also improved physiological traits and nutritional parameters, such as leaf area index, net assimilation rate, crude protein content, and digestible dry matter of forages. These findings suggest that quinoa can be incorporated into crop rotations to help address the shortage of high-quality livestock feed. Additionally, the application of zeatin and Brassinolide has the potential to enhance quinoa establishment and production in marginal soils (e.g., dry, saline).