2010 Annual Report
1a.Objectives (from AD-416)
The overall research goal is to add SSR and SNP markers to the current genetic linkage maps of a diploid blueberry mapping population (interspecific population derived from V. darrowii x V. corymbosum hybrid) developed by the USDA/ARS, Beltsville, MD, and a tetraploid blueberry mapping population (V. corymbosum) developed by the Michigan State University.
1b.Approach (from AD-416)
Genetic linkage maps will be developed for a diploid interspecific blueberry (V. darrowi x V. corymbosum) mapping population developed by the USDA/ARS, Beltsville, MD, and for a tetraploid highbush blueberry (V. corymbosum) mapping population, derived from a cross between the northern highbush cultivar ‘Draper’ and the southern highbush cultivar ‘Jewel’, developed by Michigan State University. SSR and SNP markers will be added to the current maps. Markers will be tested on parent plants first. Markers that detect differences between the parents will be followed in the appropriate mapping populations and added to the current genetic linkage maps using computer software programs such as MAPMAKER or JoinMap for the diploid population and Tetraploid Map for the tetraploid population. The populations are segregating for chilling requirement, cold tolerance, and various fruit quality traits; thus, they should be useful for identifying QTL associated with these traits.
The purpose of this agreement is to distribute part of the funds from a CSREES-funded Specialty Crop Research Initiative project entitled “Generating Genomic Tools for Blueberry Improvement” to the collaborator at the New Zealand Institute for Plant and Food Research. Genomic resources for genetic improvement are lacking in blueberry. The objectives of this project are to develop molecular markers for blueberry and add them to genetic linkage maps of diploid and tetraploid blueberry populations. Over the last year research has concentrated on the development of new simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers. A total of 186 new SSR markers were designed. Of these 51 were identified as polymorphic in the diploid blueberry mapping population and 50 in the tetraploid blueberry mapping population. Twenty-seven of the polymorphic SSR markers have so far been screened over the whole diploid population. SNP marker development has focused on the diploid blueberry mapping population and re-testing of SSR markers, previously identified as monomorphic based on product size, to detect sequence variation. A total of 96 markers have been screened so far, using high resolution melting (HRM) analysis on a Roche 480 Light Cycler, and 69 markers were identified as polymorphic. Of these, 27 have so far been screened over the whole diploid population. Data for these markers is being provided to the ADODR for map construction. This work has included the training of two American students—one from the University of Maryland, who worked at Plant and Food Research for four months (Sept – Dec ‘09) and one from Earlham College, Indiana, who worked for two months (May – June ’10) on the project. This research will ultimately be used by blueberry breeders to develop new, improved blueberry varieties through marker-assisted selection. Progress was monitored by the ADODR through phone calls and e-mails to exchange data and discuss research plans. A meeting of all the scientists and advisory board members involved on the SCRI project is scheduled for July of this year, in combination with the North American Blueberry Research and Extension Workers Conference, in Kalamazoo, Michigan.