Clonal selection in interspecific Vitis spp. hybrids resistant to the root-lesion nematode Pratylenchus brachyurus by REML/BLUP

摘要

Introduction - The disorders caused by nematodes reduce in 20 to 25% of the annual production of grapes causing great loss to the crop. In order to select grapes for genetic resistance to Pratylenchus brachyurus, we estimated the genetic and environmental coefficients of variation, the individual broad-sense heritability, and the heritability of means of clones; and predicted the genetic values (u +g) of interspecific hybrids resistant to that nematode. Materials and methods - Three segregating populations from interspecific crosses were evaluated, including 57 hybrids from the crosses between the following parents originating from the Germplasm Bank of the University of California; [C166-043 (Vitis mmanetii) x 07355-075 (V. vinifera)], [06354-047 (V. vinifera /V. rotundifolia) x Cereza (V. vinifera)], and [06354-047 (V. vitufera /V. rotundifolia) x Nocera (V. vinifera)]. The experiment was evaluated as a randomized-block design with two replicates and three plants per plot. Plants were inoculated with suspension of 600 P brachyurus species. The genetic parameters and genetic values were determined using the Restricted Maximum Likelihood Best Linear Unbiased Prediction (REML/BLUP) procedure for the traits 'root mass, 'nematodes per gram of roots, 'reproduction factor', and 'reproduction index'. Results and discussion - The ratio between the genetic and environmental coefficients of variation and the individual broad-sense heritability and the heritability of means of clones were higher than 74% for all traits, indicating efficiency and optimization in the employed procedure for the selection conditions. Conclusion - The lower genotypic values (u +g) of the 'reproduction factor' and 'reproduction index' traits predicted by BLUP were used to select 14 interspecific hybrids resistant to P. brachyurus.