|TEH, SOON LI - Cornell University|
|FRESNEDO, JONATHAN - Cornell University|
|CLARK, MATTHEW - University Of Minnesota|
|SUN, QI - Cornell University|
|LUBY, JIM - University Of Minnesota|
Submitted to: Molecular Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2016
Publication Date: 12/21/2016
Citation: Teh, S., Fresnedo, J., Clark, M., Sun, Q., Cadle Davidson, L.E., Luby, J. 2016. Genetic dissection of powdery mildew resistance in interspecific half-sib grapevine families using SNP-based maps. Molecular Breeding. 37:1.
Interpretive Summary: In grapevine breeding programs, a good parent is typically used for the development of multiple families, such that progeny in different families are often half siblings. In this study, we used two half-sibling families with the same maternal parent for genetic analysis of powdery mildew resistance. In these families, regions of chromosome 15 and chromosome 2 were responsible for powdery mildew resistance, inherited from Seyval blanc. Analyzing the families together (consensus mapping) resulted in improved precision relative to analyzing the families separately. Our work is one of the first reports in grapevine demonstrating this use of half-sibling families for genetic analysis. The DNA markers that we identified can be used for the development of new grape varieties with resistance to powdery mildew.
Technical Abstract: Quantitative trait locus (QTL) identification in perennial fruit crops is impeded largely by their lengthy generation time, resulting in costly and labor-intensive maintenance of breeding programs. In a grapevine (genus Vitis) breeding program, although experimental populations are typically unreplicated, the genetic backgrounds may contain similar progenitors previously selected due to their contribution of favorable alleles. In this study, we investigated the utility of joint QTL identification provided by analyzing half-sib families. The genetic control of powdery mildew was studied using two interspecific half-sib F1 families, namely GE0711/1009 (MN1264 × MN1214; N = 147) and GE1025 (MN1264 × MN1246; N = 125). Maternal genetic maps consisting of 1,081 and 1,651 single nucleotide polymorphism (SNP) markers respectively were constructed using a pseudo-testcross strategy. Ratings of field resistance to powdery mildew were obtained based on whole-plant evaluation of disease severity. This two-year analysis uncovered a major QTL on chromosome 15 and a minor QTL on chromosome 2 that were validated on a consensus map in these half-sib families with improved precision relative to the parental maps. Examination of haplotype combinations based on the two QTL regions identified strong association of haplotypes inherited from Seyval blanc, through MN 1264, with powdery mildew resistance. This investigation also encompassed the use of SSR markers to establish a correlation between 206-bp (UDV-015b) and 357-bp (VViv67) fragment sizes with resistance-carrying haplotypes. Our work is one of the first reports in grapevine demonstrating the use of SNP-based maps and haplotypes for QTL identification and tagging of powdery mildew resistance in half-sib families.