Crossability between cultivated and wild tuber-and non-tuber-bearing Solanums

The cultivated potato has over 200 extant wild relatives many of which cont ain genes valuable for disease resistance, hardiness, processing and agrono mic traits. Crossability of these wild species directly with the cultivated potato is complicated by several reproductive phenomena such as stylar and ploidy barriers and Endosperm Balance Numbers (EBN). However, a systematic analysis of crossability with many of these wild relatives has never fully been examined. Reciprocal crosses were made between cultivated potato and over 400 wild potato accessions; stylar barriers and 2n gamete production w ere examined as was the fertility of many of the putative hybrids. Generall y, the seed/fruit ratio increased the more closely related the species were to the cultivated potato. However, a few crosses were successful in spite of predicted failure due to ploidy or EBN differences.