Identification of Reliable Biochemical Seed Tests for Genetic Purity Determination in Bread Wheat (Triticum aestivum L.)

Genetic purity is a cornerstone of seed quality assurance, particularly in early-generation bread wheat (Triticum aestivum L.) seed production. Molecular markers such as SSRs and SNPs provide high precision for varietal identification but remain largely inaccessible in resource-limited seed laboratories due to cost, technical expertise, and infrastructure requirements. Biochemical seed tests, including phenol, sodium hydroxide (NaOH), and potassium hydroxide (KOH), exploit genetically controlled seed coat reactions and offer rapid, cost-effective alternatives. This study evaluated the effectiveness of these three biochemical assays in determining genetic purity across sixteen pre-basic bread wheat varieties under a completely randomized laboratory design. Prior to biochemical testing, physical and physiological seed quality parameters germination percentage, moisture content, hectoliter weight, and physical purity were measured to ensure uniformity. Analysis of variance revealed highly significant varietal differences (P < 0.001) for all physical traits. Among biochemical tests, NaOH exhibited the fastest, most intense, and consistent seed coat color reactions, followed by KOH, while phenol responses were weak and variable. The study confirms that NaOH, supported by KOH as a secondary assay, provides a reliable, reproducible, and low-cost approach for routine genetic purity testing in bread wheat, particularly suitable for seed laboratories in developing countries.