Cross-compatibility of Petunia pubescens and P. pygmaea with native taxa of Petunia

Abstract

Two species of Petunia sensu Jussieu having 2 n = 18 chromosomes, P. pubescens and P. pygmaea, were crossed with 46 native taxa of Petunia. Petunia pubescens and P. pygmaea failed to set any capsules when crossed with taxa having 2 n = 14 chromosomes, including a garden petunia cultivar, 'Pearl Sky Blue'. Petunia pubescens hybridized with all native taxa having 2 n = 18 chromosomes, except P. parviflora and P. pygmaea. Petunia pyg. maea hybridizes only with P. parviflora. In relation to the interspecific cross-compatibility; therefore, species of Petunia sensu Jussieu could be separated into at least three groups: 1) taxa with 2 n = 14 chromosomes, 2 two taxa with 2 n = 18 chromosomes (P. parviflora and P. pygmaea), and 3) the remaining taxa with 2 n = 18 chromosomes.