VvGAI1 polymorphisms associate with variation for berry traits in grapevine

Gibberellins have important effects over different developmental processes in plants and the exogenous application of GA(3) has been extensively used in grapevine to improve certain quality traits (to control berry size, set and weight, to decrease cluster compactness and to induce the absence of seeds in grapes). In this study, we performed association analyses using a core collection of 127 table grape accessions in order to identify causal SNPs in the gene VvGAI1, a negative regulator of gibberellins response. Seventeen quantitative descriptors, related with fertility, bunch and berry traits were used for the association analysis with VvGAI1. Fifteen polymorphisms and 15 haplotypes were identified, and some of them associated significantly with important traits for table grape: berry texture, juice yield, and bunch weight. The genetic structure found in the collection of varieties was consistent with their origins, and was included in the association test. In addition, nucleotide and haplotypic diversity, linkage disequilibrium and the possible existence of selection over the gene were also evaluated to support the association test.