An analysis of the hybrid nature ofsolanum xedinense Berth, using molecular, cytological and crossability studies

Summary Solanum xedinense Berth., a pentaploid (2n=5x=60) interspecific hybrid between the cultivated potato and the wild speciesSolanum demissum Lindl., represents evidence of genetic exchange between wild and cultivated species. It has been found in Central Mexico at altitudes between 2000 and 3500 meters, growing in and along the edges of cultivated fields, roadside thickets, forest margins and along irrigation ditches. This study examined the hybrid nature of S.xedinense using molecular, cytological and crossability data. RAPD and AFLP markers were used to supportS. xedinense as a hybrid between the cultivated potato andS. demissum. Meiotic analysis and crossability studies were used to examine the potential ofS. xedinense to form offspring. Several accessions ofS. tuberosum L. subsp.tuberosum and subsp.andigena Hawkes,S. demissum and an accession ofS. xedinense were used in the study. Artificial hybrids betweenS. tuberosum subsp.tuberosum andS. demissum were included for comparison. Molecular analysis positioned the natural and artificial hybrids as an intermediate group between the parental populations, supporting their relationship with the parental populations. Meiosis was abnormal in both natural and artificial hybrids, and reduced crossability was noted forS. xedinense. Although gene flow appears to happen between wild and cultivated potato, the potential for the natural hybrids to become established may depend mostly on their ability to clonally propagate themselves.