Diploid parthenogenetic and androgenetic plants were found in certain interspecific hybrid combinations in diploid Solarium. Self progenies of parthenotes of S. verrucosum appeared highly uniform and 100% homozygous for resistance to Race 1.2.3.4 of Phytophthora infestans. They can be of prime importance for breeding if homozygous lines are needed.
Diploid androgenetic plants occur among interspecific hybrid progenies in Solanum. They could be used to investigate the effect of different plasmons on several characters.
PARTHENOGENESIS
IN SOLANUM VERRUCOSUM, S. ETUBEROSUM AND S. BULBOCASTANUM S. verrucosum is a self-compatible, tuber-bearing Mexican wild species of potato (2n = 24) which belongs to the taxonomic series Demissa. S. etuberosum is a selfcompatible, non-tuberizing species (2n = 24) from South America and belongs to series Etuberosa. S. bulbocastanum is a self-incompatible, diploid wild Mexican species from the series Bulbocastana. The series Demissa, Etuberosa and Bulbocastana are included in the subsection Hyperbasarthrum of the section Tuberarium of the genus Solanum. When S. verrucosum, S. etuberosum and S. bulbocastanum were used as females in interspecific crossing, some seed set was obtained, which later on proved to be of nonhybrid origin; a parthenogenetic origin is suspected.
PARTHENOGENESIS IN S. VERRUCOSUM
When, after careful emasculation, S. verrucosum PI 160228 was pollinated by pollen grains from S. etuberosum PI 245939, one small berry was detected as a result of 4