Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/26/2003
Publication Date: 2/1/2004
Citation: Fery, R.L., Thies, J.A., Gillaspie, A.G. 2004. 'knucklehull-vnr', a blackeye cowpea mosaic virus and root-knot nematode resistant, crowder-type southernpea. Hortscience. 39(1):183-184. Interpretive Summary: Knuckle Purple Hull, a crowder-type southernpea cultivar widely grown by fresh market growers and home gardeners throughout the southern United States, is quite susceptible to blackeye cowpea mosaic virus and root-knot nematodes. Blackeye cowpea mosaic virus is the most devastating virus of southernpea in the U.S. and root-knot nematodes are the most devastating nematode pests of southernpea in the U.S. About five years ago, ARS researchers at the U.S. Vegetable Laboratory in Charleston, SC, and the Plant Genetic Resources Conservation Unit in Griffin, GA, initiated an effort to select a knuckle purple hull-type cultivar that is both virus and nematode resistant. These efforts resulted in the October 2002 release of the cultivar KnuckleHull-VNR. The new cultivar is highly resistant to blackeye cowpea mosaic virus and root-knot nematodes. The availability of KnuckleHull-VNR will provide fresh market growers and home gardeners an effective and efficient way for controlling yield losses to their knuckle hull crowder plantings caused by blackeye cowpea mosaic virus and root-knot nematodes.
Technical Abstract: The USDA has released a new knuckle-purple-hull, crowder-type southernpea cultivar named KnuckleHull-VNR. The new cultivar was developed as a replacement for Knuckle Purple Hull, a cultivar widely grown by fresh-market growers and home gardeners throughout the southeastern United States for many years despite susceptibility to blackeye cowpea mosaic virus and root-knot nematodes. The major attributes of KnuckleHull-VNR are its excellent resistances to blackeye cowpea mosaic virus and root-knot nematodes. KnuckleHull-VNR produces dry pods at Charleston, SC, in 68 to 74 days. A typical pod is slightly curved, 20 cm long, and contains 14 peas. Fresh peas have a semi-crowder to crowder shape and a light green color. Dry KnuckleHull-VNR peas have a brown-colored, smooth seed coat, and are smaller in size than Knuckle Purple Hull peas (weight per 100 dry peas: KnuckleHull-VNR, 15.2 g; and Knuckle Purple Hull, 19.7 g). The results of replicated trials indicate that the yield potential of KnuckleHull-VNR is similar to that of Knuckle Purple Hull. KnuckleHull-VNR is recommended for use by fresh market growers and home gardeners who are concerned about yield losses to their Knuckle Purple Hull plantings caused by blackeye cowpea mosaic virus and root-knot nematodes.