This text also appears in our 2024 seed catalog.
Research and Breeding Highlights – 2023
Continued Improvement of South Wind Slicer and Common Wealth Pickler (Twin Oaks Seed Farm)
In 2022 we took a break from our usual practice of evaluating plants individually (which we’d been doing since 2017), instead assessing blocks planted with the best 2021 selections. But in 2023 we were back at it, intensively evaluating about 50 plants of each variety – recording yields, downy mildew foliage resistance ratings, and notes about eating quality and appearance for each plant. Even though these are stable finished varieties, we want to keep improving and refining them. We’ve gotten very good feedback on Common Wealth Pickler and South Wind Slicer from up and down the East Coast – for their resilience and long life even in high disease conditions, and also for their flavor. We also grew successful seed crops of both varieties this year. See page 13-14 for variety descriptions.
Squash Seed Production in Pollination Isolation Cages (Twin Oaks Seed Farm) As part of our squash-focused SARE grant, we used pollination isolation screen cages for the first time, with three separate winter squash seed production growouts. This allows us to save seed from several varieties growing in the same field without having to hand pollinate. (Hand pollination is very labor intensive and doesn’t work for some varieties.) We used a “meso tunnel” design that we learned about from “The Current Cucurbit” project out of Iowa State. Meso means mid height, as opposed to low or high tunnels – these are made out of ½ inch x 10 foot metal conduit bent with a hoop bender to create hoops that are about 3.5 feet tall. The hoops are arranged in two rows, and covered with a 20 foot wide “Protecnet” screen cover, to create cages 11 feet wide by 50 feet long, suitable for 15-20 fully vining squash plants. We bought small bumble bee hives from a Michigan-based company called Plant Products Inc, which were successful in pollinating the squash in the cages. We got good harvests from all the cages! We’re excited to have this tool available for future seed production and plant breeding projects – it means we’ll be able to grow many more varieties in any given year.
Summer Squash Trials (Care of the Earth Community Farm and Twin Oaks Seed Farm) We trialed dozens of summer squash varieties for the first time in 2023 as part of our squash SARE grant. Previously we’ve mainly focused on winter squash.
At Care of the Earth Farm the trials included a Cucurbita pepo species trial focused on downy mildew and plectosporium blight, which has become endemic in East Tennessee. The mid-July planting had very high plectosporium blight pressure, followed by high downy mildew pressure. All of the more common open-pollinated varieties in the trial were killed by plectosporium blight. The varieties that remained were all vining varieties originally from Mexico or Guatemala, many of which we got from the USDA germplasm bank. They all had intermediate to strong resistance to downy mildew. The most resistant to plectosporium blight was “PI449350”, followed by “PI442321” and then “Tatume” and “PI438700”. The drawbacks to both “PI449350” and “PI442321” is that they are later to produce and they are vigorously vining.
We also conducted Cucurbita moschata summer squash trials at both farms. Moschata species summer squash are notable for their immunity to plectosporium blight and vine borers. Almost all summer squash in the U.S. are pepo species, but we found moschata summer squash varieties originating from Korea, Brazil, France and Italy to include in the trials. None of the varieties were affected by vine borer at either farm (Twin Oaks tends to have heavy pressure and Care of the Earth much lighter pressure).
In the first succession at Twin Oaks (planted May 25th), the most productive varieties were Teot Bat Put (an oval-shaped variety from Korea) and Longue de Nice (from France), followed by Menina Brasileira Precoce (Brazil), Tromboncino (Italy), Jin Dong Ae (Korea) and Mini Paulista (Brazil). In the second succession (planted July 15th), Menina Brasileira Precoce was by far the most productive, likely due to its standout downy mildew resistance. The Korean moschata summer squash varieties are notable for their earliness and compact vines, as well as excellent flavor and likely good marketability in terms of recognizable summer squash shape. We plan to especially work with Jin Dong Ae and Teot Bat Put in the future, as they also had good yields. Note that many of the other varieties are fully vining squash plants that need 8-10 feet row spacing. Longue de Nice showed promise but had a tendency towards blossom end rot. We’ll see if we can select against that in the future.
At Care of the Earth, the trial was conducted under high downy mildew pressure, with a 6/28 planting date and rainy conditions that persisted until mid-August. “Tromboncino” was the best producer by count and by weight, although their shape and flavor are not ideal. We were also impressed by “Mini Paulista” (a variety from Brazil) and “Trombambino LOT 22-4901” (an unreleased variety from Michael Mazourek at Cornell University) as they were fairly productive, had some DM-resistance, and had better shape and flavor than “Tromboncino”; they are both vining.
Breeding Easter In August Cherry Tomato (Twin Oaks Seed Farm)
We continued work with a cross between Garden Peach Tomato and Matt’s Wild Cherry Tomato, and are excited to now be releasing Easter In August Cherry Tomato from this cross. The variety includes pink and yellow cherries of varying shades that have the fuzzy or matte-finish skin of Garden Peach. In 2023 we selected from 30 plants. All of them had the same color and fuzziness as their 2022 parents, but there was some variation in flavor, productivity, and incidence of splitting. We evaluated each plant for these characteristics; this year’s Easter In August seedstock includes fruits from our favorite seven plants, with equal amounts of pink and yellow. These all had good flavor, good productivity, and minimal or zero splitting. The variety is also notable for its resilient and long-lived foliage. See page 33 for the full description.
Summer Lettuce Trial (Care of the Earth Community Farm)
In late summer, we compared 12 crisphead lettuce varieties for bolt-resistance, heat-resistance, flavor/bitterness, texture, resistance to bottom-rot and tipburn, size, and quickness to size up. Sierra was the best for bolt-resistance, size, quickness to size up, and tipburn-resistance and was second only to Irene Gem for flavor. None of the varieties had bottom rot despite significant rainfall, but in our spring comparison between Magenta and Sierra, Sierra showed more bottom rot resistance. We saved seed for Sierra from the spring comparison trial after selecting for type, bolt-resistance, and bottom-rot resistance, and are excited to be able to offer those seeds this season (see page 21).
Continued Improvement of Xiye Butternut and Ofelia Butternut (Care of the Earth Community Farm)
In 2023, we evaluated 20 individual plants in 8 different Xiye Butternut gene pools, evaluated 100 individual plants of our main breeding line, and did seed growouts. In the Xiye gene pool comparison, we kept data on vine length, downy mildew resistance, fruit type, consistency of fruit type, and productivity; we will also collect data over the winter on storage ability and flavor. Our intention with these growouts is to better understand the connections between plant and fruit phenotypes and storage and flavor profile. In the larger evaluation, we kept data on vine length, downy mildew resistance, fruit type, consistency of fruit type, and productivity in order to inform self and cross pollinations and for ongoing selection work. Although we continue to select for a more uniform squash, we also want to maintain several more diverse gene pools for climate resiliency and for future breeding. We were again very impressed with Xiye’s DM-resistance and productivity even in a challenging season. See page 28 for Xiye description.
We also evaluated 180 individual plants of Ofelia (a smaller sister variety of Xiye) for vine length, downy mildew resistance, fruit type, consistency of fruit type, and productivity. We were surprised by the uniformity of the plants across evaluation criteria. They were quite productive and showed good DM-resistance. We also really liked their size, right under 3#. We made several self-pollinations and cross-pollinations and hope to improve neck thickness, depth of flavor, and keeping quality in 2024.
Breeding and Continued Selection of Mira Red-Stem and Mira White-Stem Kale (Care of the Earth Community Farm)
In January and February 2023, we continued cold-hardiness selection on both Mira Red-Stem Kale, a ruffled green-leaf napus kale with beautiful red stems, and Mira White-Stem Kale, a large wavy green-leaf napus kale that looks a lot like a collard green. They were both originally selected from the Gulag Stars population in the winter of 2019-2020. We grew out winter-hardy selections of Mira Red-Stem for seed this spring, and then seeded a plot this fall to evaluate that seed lot’s consistency and performance. It was incredibly consistent (one slightly off-type plant in about 1200 plants), and has excelled in dry, hot fall weather. We are excited to release Mira Red-Stem this season. See page 19 for full description. We hope to have seeds of Mira White-Stem available soon.
Breeding Margie’s Melon (Care of the Earth Community Farm)
We seeded 6 gene pools of Greta Gene Pool melons (3 round and 3 oblong) this summer to evaluate fruit-type, consistency, Fusarium and DM-resistance, rind-thickness, productivity, storage ability, flavor, and Brix. We were very excited with Margie’s Melon, which was one of the Greta Round selections. Margie’s Melon is a productive, almost round, well-netted muskmelon with high Brix (10.5-11.5), good disease resistance, and good storage ability. It also handled above average rainfall well, with very little splitting. We also continued selection work in two Greta Oblong gene pools, which we plan to continue refining in 2024. We are excited to release Margie’s Melon this season. See page 22 for full description.
Ongoing Tomato Breeding (Care of the Earth Community Farm)
We also have a few different tomato projects that are ongoing, including a disease-resistant, late-season orange cherry tomato and a beautiful Homestead cross. We pulled the orange cherry tomato out of a planting of Wheatly’s Frost Resistant (a pink oblate cherry tomato from Adaptive Seeds) in 2016. The first couple of plantings produced a large variety of shapes and colors from yellow to orange to pink to red and everything in between. For several years, we just rogued plants that produced non-orange fruit and saved seeds only from our best orange producing plants. We were able to eliminate most of the variation in shape and color, except that a round red cherry tomato persisted along with round orange tomatoes at a rate of 10-20% of the total planting. In 2023, we isolated flower sets and saved seeds from isolated orange fruits. We are hoping for all orange fruiting plants in 2024. The Homestead cross is a cross of Homestead and an unknown parent from seedstock we received from SESE in 2022. It is a beautiful yellow tomato with pink blush, calabash or «flower» shape and is a great size (averaging 4-6oz.). It appears to have inherited resistance to heat and common diseases from Homestead. We will continue to observe it in 2024 and isolate flower sets.
Breeding Bakers Branch Butternut (Twin Oaks Seed Farm): This newly released variety comes from a 2017 cross between our South Anna Butternut and a necked offtype of Chinese Tropical Pumpkin, that was then backcrossed to South Anna by Jay Bost over the winter of 2020 in Hawaii. The resulting BC1 generation stood out in our 2020 trials. We did some selection that year, followed by intensive selection the following three years.
In 2022 we grew and self pollinated 20 separately-trained plants, then sent the best four to Chris French in Florida for recombination over the winter. Chris sent us fruits in mid May, which we processed in time to plant the first week of June this year.
Our 2023 plot was sizeable, around 130 plants, with seeds coming from the Florida growout, and from the 2022 self-pollinated plants. The growout was isolated from other squash, and we used a maternal selection approach, without hand pollinating. We grew them at 5’ in-row spacing but allowed the vines to intertwine. The foliage held up very well to downy mildew. At harvest time we traced all the fruits back to the plants in the best looking plots, around 70 plants in all. In making selections we’ve prioritized keeping quality, concentrated fruit set (avoiding plants that set late fruits they can’t mature), yields and eating quality (as measured by brix, flavor and dry matter tests). Seeds from the all-around best five 2023 plants are what we’re selling this year as Bakers Branch Butternut (they made 230 pounds of fruit between them so it’s a decent amount of seed). The squash from all the other plants we mostly sold to Broadfork Farm in Moseley, VA – they have limited acreage and aren’t able to grow winter squash, so it was a helpful addition to their CSA and farmers market stand.
Eating quality is good, with brix averaging 10.7 and dry matter averaging 15.4 for all fruits tested from the planting. They tend to have a nutty flavor, like their Chinese Tropical Pumpkin parent. See page 29 for description.
One of the 2022 selections made fruits smaller than the others – averaging about 2 pounds. Although we’ve recombined that with the other selections, we also grew them out separately, with the goal of creating a smaller version – so look for this some time in the next two years.
Corn Research and Breeding (Laughing Springs Farm): Nora and Jay moved to Western North Carolina in 2022 from Oahu where they were teaching with the new farmer program GoFarm Hawaii. Jay mentored there in Waimanalo with the tropical maize breeder Jim Brewbaker who recently passed away. Jay continues to work with some of Brewbaker’s materials which were selected over ~50 years for pest and disease resistance. Projects include sweet corn, supersweet corn, waxy corn, tropical flints, and blue dents for masa. We’d love to share seed for folks who want to try any of our work and give feedback.
Sugary Sweet Corns: the work on “old fashion” or sugary corns all is based on the variety Hawaiian Sugar – an old Hawaiian variety that was bred by J. Mangelsdorf in 1945 from crosses of Caribbean flints x Golden Bantam variety and selected since for tolerance to maize mosaic virus. We are working with populations created from crosses between Hawaiian Sugar and the variety Double Red for red sweet corn; between Hawaiian Sugar and Delectable for yellow/bi-color yellow/white; and Hawaiian Sugar crossed with Aonsu for blue sweet corn.
Brittle Supersweet Corn: Brewbaker’s breeding program was unique in using the brittle mutation versus the shrunken mutation to have “supersweet” corn, as he found brittle to perform better in soils with fusarium. These lines are in general very long season for us thus far, but we are working to shorten days to maturity, as well as to stabilize a very dark purple line with interesting pineapple flavor tones.
Orange Tropical Flints: We created the variety Nalo Orange in collaboration with Frank Kutka of Wisconsin, by crossing South American Cateto-type corn with five of Jim Brewbaker’s “synthetic” populations based on inbreds with superior disease resistance. Frank had developed a very, very dark orange Cateto-based population that was used in the cross. Over 10+ generations, this cross (which has become Nalo Orange) has been selected for performance in organic conditions, disease resistance, dark orange color, etc. It makes an excellent, highly flavorful corn meal/polenta. We continue to work with it in North Carolina and have also begun widening its genetic base further, crossing it with Zdrowie, Cargil Cateto, Orange Crush, and other Cateto and Italian polenta types. Nalo Orange is named for the town of Waimanalo, Hawaii. (Frank has released a variety from his Cateto-based population called Zdrowie through Sand Hill Preservation Center.)
Blue Masa Corns: this line of work started in Hawaii with crosses between tropical blue corns (from Mexico) and Brewbaker’s white, highly disease resistant dents (derived from Hickory King types that migrated to southern Africa). A number of cycles of selection were carried out in Hawaii and then crosses to Appalachian white dents like Mountain Rest, Cooke’s Prolific, Hickory King were carried out. In some lines, crosses have been made with Ohio Blue Clarage and more recently some crossed with Blue Mountain and Cherokee White Eagle. These are all being selected for shorter days to maturity, lower ear height, and culinary quality for hominy and masa.
Tomato Breeding (Laughing Springs Farm): While growing in Hawaii, we faced very serious pressure from Tomato Yellow Leaf Curl Virus and there were few resistant varieties available. One resistant variety was ‘Merlot,’ a red hybrid cherry tomato that we started working with. In the F3 generation we saved seed from an orange large cherry plant and this has been selected and stabilized over many generations by GoFarm Hawaii new farmers, using the name GoFarm Gold. It was for us relatively bomb proof while other tomatoes melted. We have made a number of crosses with GoFarm Gold as the donor of TYLCV resistance to larger-fruited heirloom types and are selecting for performance, flavor and disease resistance. Another line we are excited about began with a cross between Dimerosa and University of Florida’s Garden Gem.
Winter Squash Research (Laughing Springs Farm): We continue to fall down the rabbit hole of tropical moschata diversity. Standouts for us lately are descendants of the F1 Crowning from Known You Seeds and ‘Rainbow Seminole’ a population that came about between outcrossed Seminole in Hawaii with Chinese Tropical Pumpkin. We continue chasing the Green Ayote dragon and lately have been growing a number of lines that came from seed set in outcrossed Tetsukabuto (the moschata x maxima wonder squash).