2012 Annual Report
1a.Objectives (from AD-416):
This project will combine physiological and genetic expertise and infrastructure to create a rational core collection and dataset for Solanum microdontum. This species, although wild, is remarkable for its broad expression for economically important tuber traits and ease of introgression into cultivars. The goal is to characterize for physiological tuber traits, and assess the patterns of phenotypes and genetics and the interaction of the two. This will allow for the more efficient management of this species in the genebank, and its deployment for cultivar breeding.
1b.Approach (from AD-416):
Grow all populations in the genebank to produce replicate sets of tubers. Assess for the physiological traits. Assess genetic variation patterns by AFLP and/or other markers. Perform statistical analysis of link between physiological traits and genetics clusters. Thus, identify and validate core collection and identify specific markers for germplasm screening. Preserve outstanding germplasm, facilitate use by ploidy manipulation, and advertise to germplasm users.
Solanum microdontum is a diploid potato species with features that make it a good model for research into management and use of germplasm in the genebank. Its taxonomic status is unambiguous and it is in the taxonomic series of wild species closest to cultivated forms. It is represented by about 100 populations in the genebank - not too many for comprehensive evaluation, yet not too few to make prioritization of the most valuable populations worthwhile. This species is also particularly rich in desirable traits, often exhibiting very broad segregation. We used deoxyribonucleic acid (DNA) markers for selection of a representative core set with respect to economic traits. DNA was extracted from bulks of 27 plants from each of 94 populations to generate amplified fragment length polymorphism (AFLPs). A total of 1741 informative loci were detected. AFLP loci were treated as though they were traits, with the banded condition considered to be the desired state to include in a core set. At least one band unique to a population was present in 45 populations, and these 45 populations together captured 98% of all bands. Adding another 14 populations for a total of 59 captured all bands. This core set was assessed for whether it encompassed those populations known to have useful traits, including nutritional and quality components; and disease, stress and pest resistances. As with AFLP bands, all 25 of the most desirable phenotypic traits were also found in populations in the core set of 59 populations. These AFLP markers may also reveal the influence of eco-geo parameters, and introgression from other species.
This research relates to Sub-objective 2B., Incorporate phenotypic (evaluation) data from “in-house” studies of vigor; late blight resistance; gibberellin mutants; and tuber anti-oxidants, acidity, calcium, potassium, and anti-cancer PCI into GRIN and/or other databases.