Foliar Applications Improves Grapevine Plant Cold Hardiness

Abstract

Understanding and enhancing the cold hardiness of vines is crucial for viticulture, as it directly impacts the sustainability and productivity of vineyards in diverse climatic regions. This study, therefore, meticulously examined grapevine responses to various treatments and sampling times, revealing nuanced dynamics in cold tolerance, physiological parameters, and growth outcomes. Our study found that treatments like K2SO4 significantly enhanced grapevine cold hardiness. Specifically, K2SO4 showed high R2 values, indicating a substantial improvement in low-temperature hardiness for primary buds and in processes like bud burst and sprouting. Our results also revealed significant differences in cold hardiness across various treatments and sampling times, with K2SO4 leading to the highest LT50 value for primary buds. Additionally, in single-bud cuttings, K2SO4 application improved viability rates, root and shoot growth, and rooting rates, particularly observed in January. Growth parameters in single-bud cuttings further illustrated the impact of treatments, with the viability rate of primary buds being 61.5 % in the K2SO4 application and 62.0 % in the CaCl2 application. The highest root length of 2.5 cm and shoot length of 3.4 cm, along with a rooting rate of 61.0 %, root scale of 1.4, root number of 6.9, and basal callus rate of 24.6 % were obtained from the K2SO4 application. Our research found that the applications of K2SO4 and CaCl2 increased the cold hardiness of the buds and phloem tissue of the vine by approximately 1 degrees C compared to the control. It has been concluded that K2SO4 and CaCl2 applications during development can reduce the cold injury rate and economic losses in vines in areas with high risk of winter cold damaging events. The comprehensive findings of this study offer actionable insights that can significantly contribute to the refinement of vineyard management practices, promoting optimal grapevine performance and hardiness in the face of varying cold conditions.