Estimation of effectivity of new growth regulators on winter wheat productivity and quality

Abstract

Triazole derivatives are powerful agronomic tools that regulate multiple plant processes. In wheat, they help balance veget a tive and reproductive growth, enhance tolerance to abiotic and biotic stresses, and support stable, high yields with improved grain quality. Their dual functionality as growth regulators and broad-spectrum fungicides enables integrated, resource-efficient pr o grams that couple crop protection with physiological stimulation. In this study, seeds from five winter wheat varieties (1.000 grains per treatment) were primed in aqueous solutions of two triazole-type compounds, CA-64 and CA-79, at 0.01%, 0.02% and 0.04%. Soaking lasted 24 hours under standard protocols for plant growth stimulants; water-soaked seeds served as controls. Triazole - based seed priming is increasingly used to fine-tune early crop physiology, yet concentration-response windows and genotype specificity remain underdefined for winter wheat. Two triazole agents have been evaluated across varieties and me a surement systems and a narrow, repeatable stimulatory window was found at 0.01–0.02% with a consistent toxicity threshold at 0.04%. Within the effective range, CA-79 outperformed CA-64 for photosynthetic status (SPAD and calculated chlorophyll), grain yield, yield components (grain weight per main spike, total grain weight per plant, thousand-grain weight (TGW) and grain quality ) . Responses were robust across years and genotypes, with the largest advantage of CA-79 at 0.02%, particularly in MIP Feeriya and the western ecotypes (MV Nador, MV Menrot), while still conferring clear gains in local varieties (Pozitsia Odeska, Tenor). CA-79 (0.02%) reliably increased protein and wet gluten and shifted the glutenin profile toward higher HMW fractions without inflating LMW glutenins , which was an advantageous pattern for baking strength. CA-64 at 0.02% was a safe, positive alternative, though the magnitude of improvement was generally smaller. At 0.04%, both agents depressed photosynthetic indic a tors, yield, and quality indices; HMW glutenins declined most, underscoring a clear toxicity boundary that should be avoided. Genotype conditioning was evident. Local genotypes showed predictable uplift at 0.02% (CA-79 preferred, CA-64 dependable as fallback). Western ecotypes benefited at 0.01–0.02%, with CA-79 providing a broader margin; doses above 0.02% are not re c ommended. Operationally, CA-79 at 0.02% is the default choice for maximal, balanced improvements in photosynthetic capac i ty, yield, and baking quality. Where risk aversion or seed-lot sensitivity warrants caution, 0.01% offers a gentler yet significant uplift. CA-64 (0.01–0.02%) remains a practical second line when access or regulatory status limits CA-79. 0.04% should be avoided for both compounds. These findings delineate concentration-genotype operating zones for triazole priming in winter wheat and highlight CA-79 as the leading option at 0.02% concentration. Ongoing work will extend the assessment to micron u trient enrichment (Fe, Zn, Cu, Mn) to link physiological stimulation with nutritional quality gains.