Genome size variation in natural populations of wild potato species from west Argentina

Abstract

Wild potato species (Solanum, section Petota) have great ecological adaptability and represent essential genetic resources for the improvement of the third most important food crop worldwide. From more than 100 species described for this section, the genome size has been established for only 12. The aims of this work were to: contribute data on the C-values for Solanum species; assess the degree of interspecific and intraspecific genome size variation; investigate correlations between genome size and bioclimatic variables; and determine whether the data for genome size are helpful for delineating taxa. The DNA contents of 97 genotypes from 28 populations and two accessions of seven wild potato species, including diploids, triploids, and tetraploids, were measured by flow cytometry. Statistical genome size differences within and among species were found. The natural interploidal hybrid Solanum × rechei had the highest intraspecific genome size variation. The tetraploid S. acaule presented the smallest monoploid genome size (0.72 pg), whereas the triploid cytotype of S. microdontum was the largest (0.82 pg). Correlations among bioclimatic and geographic variables and genome size were found in most species. The roles of hybridisation and polyploidisation events on genome size variability are discussed.