PREMISE OF THE STUDY: The garden petunia is derived from Petunia axillaris (white flowered) and a purple-flowered species in the P. integrifolia group; it is still unclear which purple-flowered species was used in the initial crosses. This widely cultivated hybrid is an ideal model for different areas of scientific inquiry. METHODS: We analyzed three taxa of the P. integrifolia group considered to be the most probable parental candidates, along with a random sample of garden petunia representatives that were selected for their genetic variability. We used cpDNA trnH-psbA and trnS-trnG haplotypes and seven nuclear microsatellites in a population approach to investigate the genetic variability. This is the first time information from plastid DNA sequences and nuclear microsatellites has been combined to infer evolutionary relationships in these taxa. KEY RESULTS: Our results suggest that P. interior is the purple ancestor of garden petunias, and we postulate that the initial crosses must have been between both parents as a mother plant. CONCLUSIONS: Our work will contribute to the clarification of the evolutionary relationships among the Petunia ×hybrida and P. integrifolia taxa group and could be useful in breeding programs to transfer desired traits from wild to cultivated species.
PREMISE OF THE STUDY: The garden petunia is derived from Petunia axillaris (white flowered) and a purple-flowered species in the P. integrifolia group; it is still unclear which purple-flowered species was used in the initial crosses. This widely cultivated hybrid is an ideal model for different areas of scientific inquiry. METHODS: We analyzed three taxa of the P. integrifolia group considered to be the most probable parental candidates, along with a random sample of garden petunia representatives that were selected for their genetic variability. We used cpDNA trnH-psbA and trnS-trnG haplotypes and seven nuclear microsatellites in a population approach to investigate the genetic variability. This is the first time information from plastid DNA sequences and nuclear microsatellites has been combined to infer evolutionary relationships in these taxa. KEY RESULTS: Our results suggest that P. interior is the purple ancestor of garden petunias, and we postulate that the initial crosses must have been between both parents as a mother plant. CONCLUSIONS: Our work will contribute to the clarification of the evolutionary relationships among the Petunia ×hybrida and P. integrifolia taxa group and could be useful in breeding programs to transfer desired traits from wild to cultivated species.