Developing drought and heat-resistant grapevine cultivars through marker-assisted breeding

Climate change poses significant challenges to viticulture, particularly through increased drought and heat stress. This study integrates physiological, biochemical, genomic, and field performance assessments to identify traits and genetic markers associated with stress tolerance in five grapevine cultivars: Cabernet Sauvignon, Chardonnay, Syrah, Merlot, and Riesling. Genomic analysis revealed specific SNP markers on chromosomes 4 and 8, linked to water-use efficiency (WUE) and proline accumulation, crucial for osmotic balance under drought conditions. Physiological assessments showed that Cabernet Sauvignon and Merlot maintained high relative water content and low stomatal conductance, reducing water loss. Biochemical analysis indicated that Chardonnay and Syrah had elevated heat shock protein (HSP) expression and low malondialdehyde (MDA) levels, supporting cellular stability under heat. Field trials further validated these traits, with Cabernet Sauvignon and Chardonnay demonstrating yield stability and high sugar content despite stress. This research underscores the potential of marker-assisted breeding to develop climate-resilient grapevine cultivars, offering practical insights for sustainable viticulture in the face of global climate shifts.