Graduate Student Missouri State University Springfield, Missouri
Body of Abstract: In grapevine, the impact of the root system on the performance of the vine is well established, but the genetic basis of the architecture of the root system has yet to be investigated. In this study, we analyzed the root system architecture (RSA) of interspecific F1 hybrid progeny from a cross between a Vitis rupestris Scheele (♀) and a Vitis riparia Michx (♂) plants, representing two species that have been foundational for the breeding of rootstock cultivars. We generated and characterized adventitious root systems from dormant cuttings of the 162 F1 vines and by extracting 35 phenotype elements (phenes) of the RSA from two-dimensional images using the software RhizoVision Explorer. Principal component analysis (PCA) revealed that the proportion of variance explained by PC1 was 71.04%. Using a GBS marker-based integrated linkage map and of this F1 progeny, we performed QTL analysis using a pseudo-testcross strategy. Several significant QTL (p< 0.05), all on chromosome 10, were identified. Two paternal QTL were located, one near a telomere and other 8.9 cM away from it; they determined 13.1 % and 12.6% of the variance in the number of roots and the depth of the root system, respectively. A maternal QTL was found in the region between 26.1 and 29.5 cM for root system width, explaining 13.7 to 15.9% of the variance. Another maternal QTL at 21.1 cM also contributed to width, explaining 16% of the variance and also influenced the depth, the perimeter, the lower root area, and the number of roots of the root system. Interestingly, when we used scores derived from PC1 as phenotype, a QTL was identified that mapped to the same marker at 21.1 cM, explaining 12.4% of the variance in the overall RSA phenotype, though this QTL was significant at p< 0.059.
