Blast from my petunia past

A few days ago I recorded a podcast with Margaret Roach were we talked about all our favorite seed sources. One of the many things we mentioned were the great species petunias available from Select Seeds. Which caused me to flash back to my time in graduate school doing research on petunias, and dig up these old images.

Petunia integrifolia (top left) Petunia axillaris (top right) and their F2 hybrids (everything else)
Petunia integrifolia (top left) Petunia axillaris (top right) and their F2 hybrids (everything else)

At the top are Petunia integrifolia (purple) and Petunia axillaris (white) and below are an assortment of flowers from a population of F2 hybrids between the two. This cross is interesting because it is a recreation of the original hybrid that created modern hybrid petunia.

Petunia exserta (top left) Petunia axillaris (top right) and their F2 hybrids (everything else)
Petunia exserta (top left) Petunia axillaris (top right) and their F2 hybrids (everything else)

But more fun is a similar cross with the one hummingbird pollinated petunia, P. exserta! It is fun to see the ways the colors and flower forms recombine in new ways in the seedlings.
I don’t have anything profound to say about these pictures… just, hey, isn’t genetics cool?
Joseph Tychonievich

Published by

Linda Chalker-Scott

Dr. Linda Chalker-Scott has a Ph.D. in Horticulture from Oregon State University and is an ISA certified arborist and an ASCA consulting arborist. She is WSU’s Extension Urban Horticulturist and an Associate Professor in the Department of Horticulture, and holds two affiliate associate professor positions at University of Washington. She conducts research in applied plant and soil sciences, publishing the results in scientific articles and university Extension fact sheets. Linda also is the award-winning author of five books: the horticultural myth-busting The Informed Gardener (2008) and The Informed Gardener Blooms Again (2010) from the University of Washington Press and Sustainable Landscapes and Gardens: Good Science – Practical Application (2009) from GFG Publishing, Inc., and How Plants Work: The Science Behind the Amazing Things Plants Do from Timber Press (2015). Her latest effort is an update of Art Kruckeberg’s Gardening with Native Plants of the Pacific Northwest from UW Press (2019). In 2018 Linda was featured in a video series – The Science of Gardening – produced by The Great Courses. She also is one of the Garden Professors – a group of academic colleagues who educate and entertain through their blog and Facebook pages. Linda’s contribution to gardeners was recognized in 2017 by the Association for Garden Communicators as the first recipient of their Cynthia Westcott Scientific Writing Award. "The Garden Professors" Facebook page - www.facebook.com/TheGardenProfessors "The Garden Professors" Facebook group - www.facebook.com/groups/GardenProfessors Books: http://www.sustainablelandscapesandgardens.com

3 thoughts on “Blast from my petunia past”

  1. I think one of the biggest mistakes amateur/hobbyist plant breeders make (and I’m guilty here myself) is not growing out enough seedlings, especially of F2 and backcross generations, or crosses between two hybrids. As you show, the range of variation can be huge even with a relatively limited gene pool of just two species. The more you grow, the greater the range of variation you’ll see, the better your choices to select from, and the better likelihood of getting those one or two rare but really great outliers. The F1 generation between two species will usually (not always!) be fairly uniform, but even then you can get some subtle variation among the siblings, especially if the parents are wild-collected and have a good degree of natural but hidden heterozygosity (as wild populations often do).

    1. I totally agree — I selected the 9 flowers in each image as the most extreme forms from populations of several hundred seedlings. If you just grew a couple dozen seedling from each of these crosses you’d miss out on a lot of cool things. Breeding is, a lot of the time, a numbers game. The more you can grow, the more cool things you’ll find.

  2. I find hybridisation fascinating and wonder how many natural species arise by this process.
    The mischievous might suggest most of them!

Leave a Reply