The last year has been a mess. I'm fine. My family is fine. Most of my friends are fine. The increased anxiety and stress basically shut off any motivation or ability I had to write posts here. I was still active over on twitter or instagram, as those require less focused thought, but I just couldn't will myself to sit down at a computer and type up anything I felt was worthwhile to post.
I'm now fully vaccinated against covid19, but I know there are many people who still have not been able to access a vaccine. Some in my family. Many in the broader community. Covid cases in my community are dropping, but they're still higher than the peak we had in May of last year. I worry about recent CDC guidance and how people broadly seem to think it means the pandemic is over. It is not. Not here, and not elsewhere.
For now, most people locally seem to still be keeping up distancing and masking practices gained over the last year. As always, the next few weeks will be informative.
Even with the persistent writer's block, I routinely thought about
writing something. This post is the first something to come of that. It isn't really the long and information or photo rich posts I like to write, but it is what it is
My plant breeding projects have continued without interruption. My gardens have provided me with useful exercise and amusement.
Most of my plant breeding projects start with hybrids between divergent varieties within one species. The F1 generally stands out from the two parental lines, so Iit is fairly easy to have confidence that the cross took. In the F2 generation, there are almost always useful and unexpected traits which segregates out.
Last year I grew out a F2 population of scarlet eggplant. Every plant was different, but two stood out. One was extra productive and ripened fruit far earlier than any others. The other developed fruit that were white when immature, but ripened to the typical red later. This season I have F3 populations from those two plants.
I still haven't figured out how to like eating eggplant, especially the more bitter flavors of the scarlet eggplant, but I like the plants and will continue to try.
Recently I found some references describing successful hybrids between the scarlet eggplant (Solanum aethiopicum) and more common purple eggplant (S. melongena), with some significant effort in the lab. This got me thinking about what species one could make hybrids with among the eggplant. Any such hybrids would allow for much more diverse F2 populations, with their higher potential for selection towards interesting new traits.
This led to some discussion about primary (1'), secondary (2'), and tertiary (3') germplasm. 1' germplasm includes plants in the same or related species which can cross readily to your subject species. 2' germplasm includes plants which can cross to your subject species with significant reduction in fertility. 3' germplasm is then plants that can cross with your subject only with intensive laboratory operations such as embryo rescue or induced genome duplication.
In the case of eggplants, there has been much more exploration of 2' and 3' germplasm for the common eggplant. The scarlet eggplant is an important crop for many communities, but it has not attracted as much attention in communities with higher levels of biological research investment. As such, the 2' and 3' germplasm lists below for scarlet eggplant are very much incomplete.
Asian Eggplant (Solanum melongena)
- primary: S. incanum and S. insanum.
- secondary: S. anguivi, S. dasyphyllum, S. lichtensteinii, S. linnaeanum, S. pyracanthos, S. tomentosum, and S. violaceum.
- tertiary: S. elaeagnifolium, S. sisymbriifolium, S. torvum, and S. aethiopicum.
Scarlet Eggplant (Solanum aethiopicum)
- primary: S. anguivi, S. macrocarpon, and S. dasyphyllum
- secondary:
- tertiary: S. melongena.
Professional plant breeders pursue traits from related species like these to improve disease resistance, drought resistance, or other traits important to growing large crops.
Independent plant breeders can afford to use traits from related species (among the 1' and 2' germplasm resources at least) to express their creativity towards developing new varieties. Even if you're not sure what to do with them (as I am), they're still lovely plants which might be fun to work with in the garden.
I hope you are and remain well as the pandemic continues.
References
- S. melongena germplasm.
- S. aethiopicum germplasm
- www.researchgate.net/publication/264393961_Conventional_and_phenomics_characterization_provides_insight_into_the_diversity_and_relationships_of_hypervariable_scarlet_Solanum_aethiopicum_L_and_gboma_S_macrocarpon_L_eggplant_complexes
- www.sciencedirect.com/science/article/abs/pii/S088915751500232X
- https://www.frontiersin.org/articles/10.3389/fpls.2017.01484/full
- Fertility restoration in S. melongena x S. aethiopicum hybrids.
- Primary, secondary, and tertiary gene pools.
