Preliminary greenhouse screening of eight grapevine rootstock cultivars under progressive water-table depletion and SSR diversity
Marco Antônio Tecchio, Rodrigo Brisola Rocha, Guilherme Ferreira Melchert, Leonardo Silva Campos, Mara Fernandes Moura Furlan, José Luiz Hernandes and Evandro Vagner Tambarussi
Abstract: Selecting grapevine rootstocks that are tolerant to drought has become crucial for the sustainability of viticulture. This study evaluated the quantitative and molecular genetic variability of eight rootstocks subjected to progressive water depletion while cultured in a greenhouse. Several plant mass traits were analyzed, and six SSR markers were used to assess molecular diversity. While heritability for leaf traits varied, stem diameter exhibited a distinct pattern where genotypic differentiation and heritability estimates increased significantly under severe water deficit, ensuring reliable selection accuracy. Additionally, our BLUP analysis indicated that clones IAC 313 Tropical, IAC 766 Campinas, and Paulsen 1103 performed best by the end of the stress period. The SSR analysis grouped the genotypes together while revealing a high genetic diversity among all the rootstocks (He > 0.70). We concluded that late-stage stem diameter was a reliable but indirect selection criterion for drought tolerance.