<b>β</b>-Aminobutyric Acid Promotes Germination of Aged Triticale Seeds and Alleviates Oxidative Stress

β-Aminobutyric acid (BABA) is a physiologically active plant compound that has not been extensively studied. It has been shown to increase resistance to biotic and abiotic stress factors and enhance seed germination in certain plant species. However, its effects on cereal grains with low germination rates have not yet been studied. This study investigated the effects of BABA on the germination of aged triticale seeds, the metabolite content of seedlings, and the state of their antioxidant systems. The study found that a three-hour treatment of seeds in BABA solutions at concentrations ranging from 0.1 to 1.0 mM increased germination energy and germination (by 10%–14%) and enhanced the accumulation of shoot and root biomass (by 17%–26%). Additionally, amylase activity increased in the grains, and the accumulation of osmolytes (sugars and proline) increased in the shoots. The content of anthocyanins in shoots increased by almost twofold, and the activity of antioxidant enzymes (superoxide dismutase, catalase, and guaiacol peroxidase) increased by approximately 20%–30%. Simultaneously, BABA seed priming caused a noticeable decrease in the levels of hydrogen peroxide and lipid peroxidation products in the shoots of seedlings. The conclusion was made that the use of BABA as a bioregulator has the potential to enhance the germination of seeds with low sowing qualities. This is due to the ability of BABA to activate the metabolism of reserve substances in the grain and prevent the development of oxidative stress.