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Tuesday, March 22, 2016

Making my own Carrots 4

I've been breeding my own carrots over the last few years. Because carrots have a biennial life-style (growing roots the first year and flowering the second), it takes an extended time to see any results of your work. My main goal has been to breed up a locally-adapted mix of carrots enriched with red and purple shades.

The basic outline for the project:
  • [2013] Grow mixed varieties of carrots, including as many intensely colored forms as can find. Select roots for diverse color and vigor.
  • [2014] Roots selected for survival in fridge. Grow final selections for flowering; allow open crossing; save seed.
  • [2015] Plant seed densely. Select for apparent F1 hybrids, vigorous roots with colors intermediate between parent types.
  • [2016] Roots selected for survival in fridge. Grow final selections for flowering; allow open crossing; save seed.
  • [2017] Grow (F2) carrots, eat carrots, enjoy life. Make selections.
  • [2018] Grow selections to flowering.
  • Cycle the steps for the last two years until project is 'complete'.

I planted "Atomic Red" carrots into the original mix, but at the end of the first growing season I had no roots with the pretty lycopene-red color of the variety. I also planted "Cosmic Purple" carrots, which have a thin layer of anthocyanin-purple skin over a more typical orange core (giving an overall purplish look), didn't do well in my garden and survived winter storage poorly. "Solar Yellow" and "Lunar White" carrots did very well in the garden and in storage. Orange "Bambino" carrots also did reasonably well.

My first parental generation of carrots was 3 "Solar Yellow", 3 "Lunar White", 4 "Cosmic Purple", 1 "Bambino", and 1 "Purple Haze" (I think. I picked it up from a farmer's market). Two or three of the "Cosmic Purple" plants decided not to bloom, so the final population was heavier on genetics for white and yellow than I had originally planned.

1. White and yellow mess.
I didn't take any useful photos of the next generation plants during the growing season. The planting grew stridently and produced some really large roots, along with many smaller ones. We didn't thin the planting sufficiently, but we got way more mass of carrots than we could eat. (Nearing the end of March now, I'm still giving carrots to friends.) This first generation from saved seed ended up being mostly various yellow and white shades, but there were enough colorful roots to keep the project moving forward.

2. Purple blush hybrids.
Several of the roots that survived storage into 2016 are obviously hybrids. Three large roots had "Cosmic Purple" as a parent, with "Solar Yellow" or "Lunar White" being the other parent. These roots (in image 2) are pale in color, with a blush of anthocyanin-purple covering the surface. I was struck by how pretty these roots were when I first pulled them out of the ground.

3. Orange/yellow hybrid.
One large root has a yellow core and an orange medulla (at left in image 3), a combination of colors not found in any of the parent varieties. I suspect this one had "Bambino" and "Solar Yellow" as parents. I only found one root with this color combination.

4. Small hybrids.
Among the smaller roots that appeared to be hybrids, there is a mix of traits. One root appears to have a purple medulla (like "Purple Haze"), but clear/white skin. (The second from the left in bottom of image 4.) One root has a purple skin (like "Cosmic Purple"), but has white flesh. (The left in top and bottom of image 4, compared to "Purple Haze" at the right end of the top.) A few others have the same purple skin, but have flesh showing a gradient between white and orange. Some of these roots are obviously alive and growing new greens, but for some of the most interesting ones it remains unclear if they will be able to contribute genetics to the next generation.

5. Preparing for growth.
I've put all the hybrids in water and under light. I hope that some of the more interesting hybrids wake up and show some new green growth.

The reason I'm so focused on the obvious hybrids is because by virtue of them being hybrids, they're heterozygous for genes involved in the formation of interesting colors. In the next generation of seeds produced from crossing these plants, there will be all sorts of interesting segregants. What this means to non-biologists is that the next generation of carrots will include both very light and very dark colored specimens.


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