He’s Breeding Better Sweetpotatoes

He’s Breeding Better Sweetpotatoes CROPS New Crops If there were a Super Bowl for sweetpotatoes Dr Phillip Wadl’s would be in the running The USDA Agricultural Research Service ARS research geneticist is breeding sweetpotatoes to compete with weeds and resist insect and nematode pests while improving other traits as well “Every year we improve weed tolerance and insect resistance while incorporating better root traits skin color and flesh color ” says Wadl “We’re also breeding in more diversity in colors such as yellow and purple varieties ” Wadl conducts research at the U S Vegetable Laboratory in Charleston S C He leads breeding efforts to improve sweetpotatoes in a program that’s nearly 75 years old He’s also an active participant in the National Sweetpotato Collaborators Group which is open to anyone interested in sweetpotato research and includes university and non-profit researchers and growers “Sweetpotato breeders can enter germplasm into the research trials ” says Wadl “Participants grow material under local production practices to assess performance in multiple environments This year there are 8 to 10 sites across the country from South Carolina to California ” Wadl’s weed competitive varieties were selected for upright growth instead of the more common on-ground vining He reports there are around 20 varieties with an erect growth habit in the ARS sweetpotato germplasm repository and another 50 with semi-erect growth “We’re looking for very vigorous growing plants that quickly cover the bare soil within a row to reduce weed competition ” says Wadl “The goal is for them to quickly fill in the row and yet be easy to cultivate Not many did that when we started our breeding objective ” Wadl has one advanced breeding line that he thinks has potential for commercial release pending further evaluation “We have others we’re now evaluating ” he says Developing a competitive cultivar is detailed time-consuming work that can span years In the case of his weed competitive cultivars Wadl has one chance per growing season to evaluate He screens seedling plots at about 6 to 8 weeks to identify competitive individuals and then evaluates these further in replicated plots Wadl is also working on incorporating root-knot nematode resistance Advanced selections are grown for 8 to 10 weeks in a greenhouse under controlled conditions dug up and the roots are washed and assessed for root galling and reproduction by counting nematode eggs They’re also screened for resistance to ground-dwelling insect pests such as wireworms sweetpotato flea beetles white grubs and the sweetpotato weevil This process takes about 2 mos “We try to combine resistance for all these pests into one breeding line We’re looking for improvement with significantly higher or at least comparable resistance levels to material currently produced in the U S ” Wadl encourages interested FARM SHOW readers to get involved A good starting point is the 2024 Southeast U S Vegetable Crop Handbook It lists sweetpotato cultivars with recommendations by states in the Southeast planting dates pest resistance fertility plant bed nutrients and more Not limited to sweetpotatoes it’s a comprehensive 365-page vegetable growing guide with extensive information that’s not regionally specific For those serious about sweetpotato research Wadl suggests contacting the U S Sweet Potato Council and the local extension service “The National Clean Plant Network is also a good resource for sweetpotato propagation material for bona fide growers ” says Wadl Contact: FARM SHOW Followup Dr Phillip Wadl USDA ARS U S Vegetable Laboratory 2700 Savannah Hwy Charleston S C 29414 ph 843-402-5388; phillip wadl@usda gov; www nationalcleanplantnetwork org/sweetpotatoes

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