In partnership with the University of California—UCDavis, this study intends to develop downy mildew-resistant grape cultivars with good agronomic traits. Hence, the goals of this research were to estimate the genetic parameters, via REML/BLUP, of variables related to downy mildew resistance in a population composed of 63 interspecific hybrids and to select promising clones on the basis of genotypic values for the breeding program of the grapevine. The experiment was conducted in randomized blocks with three replicates and one plant per plot. The evaluations were carried out in two different seasons and focused on determining disease severity. The severity data provided the basis for calculating the area under the disease progress curve (AUDPC) and the maximum severity (Smáx). Differences in the severity of downy mildew symptoms were reported among the 63 genotypes of Vitis spp., such as immune individuals (score 0) and highly susceptible to the AUDPC (3146.67) and Smáx (80.56) variables in the two seasons analyzed. The high genotype correlation seen for AUDPC (80.95%) and Smax (89.68%) suggests that the majority of genotypes had a similar response in terms of symptom severity in the two seasons evaluated. The greatest proportion of genetic variance was resulting from the effects of dominance, which corresponds to 244,165.9580 and 179.83, for AUDPC and Smax, respectively, suggesting that hybridizations are viable in the introgression of the resistance. Consequently, the values for individual heritability of the effects of dominance were greater (50.34 and 52.83%) for the AUDPC and Smax variables, respectively. It is thus recommended that the 20 most resistant genotypes, with lower genetic values for the two variables analyzed, be selected and crossed with Vitis vinifera genotypes to obtain resistant hybrids.

中文翻译：

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葡萄属种间杂种抗性的展望。葡萄球菌

本研究与加州大学戴维斯分校合作，旨在开发具有良好农艺性状的抗霜霉病葡萄品种。因此，本研究的目标是通过 REML/BLUP 估计由 63 个种间杂种组成的种群中与霜霉病抗性相关的变量的遗传参数，并根据基因型值选择有希望的克隆，用于育种计划葡萄藤。该实验在随机区组中进行，每个小区有 3 个重复和一株植物。评估在两个不同的季节进行，重点是确定疾病的严重程度。严重性数据为计算疾病进展曲线下面积 (AUDPC) 和最大严重性 (Smáx) 提供了基础。在分析的两个季节中，63 种葡萄属的基因型报告了霜霉病症状严重程度的差异，例如免疫个体（得分 0）和对 AUDPC (3146.67) 和 Smáx (80.56) 变量高度敏感。AUDPC (80.95%) 和 Smax (89.68%) 的高基因型相关性表明，在评估的两个季节中，大多数基因型在症状严重程度方面具有相似的反应。最大比例的遗传变异来自优势效应，分别对应于 AUDPC 和 Smax 的 244,165.9580 和 179.83，表明杂交在抗性基因渗入中是可行的。因此，对于 AUDPC 和 Smax 变量，优势效应的个体遗传力值分别更大（50.34 和 52.83%）。