WILD POTATO GENETIC RESOURCES CONSERVED IN SOUTHERN BRAZIL: CURRENT KNOWLEDGE AND FUTURE PERSPECTIVES

Since 1986, Embrapa Clima Temperado, Pelotas, RS, Brazil (31°40′42″S, 52°26′22.5″W), has been developing activities aimed at conserving and using wild potato (Solanum sect. Petota) genetic resources that are geographically dispersed in southern Brazil. Field trips in Brazil between latitudes 26°S and 33°S resulted in collections of more than 250 accessions, and at present, 123 accessions are effectively conserved. These are distributed as 101 accessions of S. commersonii subsp. commersonii, 18 of S. commersonii subsp. Malmeanum and four of S. chacoense subsp. muelleri. These genetic resources have been evaluated for several agronomical traits. Dry-matter content ranges from 24.05% to 40.08%, reducing sugars from 0.16% to 2.77% in the autumn cropping season and from 0.12% to 0.67% in the spring cropping season; resistance to Phythophtora infestans varies from susceptible to moderately resistant; microsporogenesis behavior ranges from 3.7% to 50.7% of abnormal cells; and pollen viability assessed by vitro germination ranges from zero to 78.8%. The genetic similarity estimated among 110 accessions based on four isoenzymatic systems ranges from 8.0% to 100%. These results suggest that the wild potato germplasm from southern Brazil carries genes of great interest for potato improvement. Future assessments of the collection will be conducted among selected wild genotypes and haploids from elite potato clones, as well as the evaluation of the germplasm for more horticultural traits. Efforts to expand the germplasm collections will continue to ensure the preservation of southern Brazilian potato genetic resources.