Rhubarb production is set to ramp up majorly in the 2025 growing season.
Varietal development is also on the horizon.
The USDA National Plant Germplasm System is an amazing resource that has allowed me to begin research on varietal development. After accessing their database, I found 41 accessions that are available for plant research. I took a look at a few different stats such as color after mash, brix, pH, source date, and accession origin. I have put in a request for 10 varieties. Selection mostly focused on color after mash, because your local bakers love to retain that signature red and brix so that it’s sweetness can complement rhubarb’s natural tartness. Here’s the full list of accessions (the top 10 are the ones I have requested) with data.
Research Proposal to NPGS
I would like to obtain these accessions for the purposes of breeding a high brix, color retentive after cooking rhubarb cultivar. I have been growing Canada Red (not listed in this request) rhubarb in my field for three years, so I am confident in my ability to grow this crop as well as in the condition of my soil and an adequate climate for rhubarb to thrive. Soil in that plot had a 6.0 pH last fall.
I started selection of these accessions by looking at statistics on color after mash, brix (averages across all three measurements), and pH (averages across all three measurements) across the 41 available accessions on GRIN. I included color after mash because my current market outlets are looking for these qualities. Bakers, in particular, are looking for better red color after mash. I included accessions mostly with brix averages over 3.5 to help with sweetness. My thinking with looking at pH was that pH can impact perceived sweetness. I could not find any conclusive way to measure perceived sweetness (it is after all relative), when looking into how pH and brix potentially interact.
YEARS 1 & 2: My research plan is to allow the crowns to mature without harvest for the first *two years, removing seed pods as soon as they develop. *In the fall of the second year, I plan to take at least one stalk of each plant to conduct color after mash and brix measurements. I know a local viticulturist, wine maker, and farmer friend who will lend me their lab to conduct the analysis.
YEAR 3 & 4: By the start of year three I should know which varieties do best in my field. In the third year, I will take crown divisions of the highest performing across color after mash and brix. Color after mash will take precedent over brix due to market demands; bakers have indicated that they can always add more sugar. I still want to take brix into account for breeding, and I would like to select ones that rate 3.5 or higher. There are only three accessions out of the ten I have selected that have an average under 3.5 brix. These divisions will be isolated on a different part of the farm for seed production. Years three and four will be spent in vegetative growth, again removing the seed pods as soon as they emerge.
YEAR 5: Selections from year three, isolated from the original plantings and existing Canada Red production area, will be allowed to go to seed to cross-pollinate each other. Plants will be closely observed for seed pod development. Early plants will have their initial seed pods removed, and efforts will be made so that all plants are putting up seed stalks of the same maturity at the same time. This will be done in order to promote the most cross-pollination across all samples.
YEAR 6-9: Seeds collected from year five will be grown out en masse and plants that exhibit deep red petiole phenotypes will be selected for planting out in another isolated part of the farm. Color after mash and brix testing will be done on these plants in year seven through nine. If necessary, plants that are testing low on color after mash and brix will be culled. Year nine is the target year for a new set of seeds where the process will continue.