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- Author or Editor: Dyremple Marsh x
Abstract
Cowpea [Vigna unguiculata (L.) Walp] has not been considered as a doublecrop alternative in the midwestern United States. Forage potential of cowpea following green peas (Pisum sativum L.) was studied in two field experiments in central and southern Minnesota. Dry-matter yield was higher in 1981 than in 1982 for all cowpea cultivars tested. Increasing the plant population improved yields for ‘California Black-eye Number 5’, ‘Alabama Giant Blackeye’, ‘Freezegreen’, and the breeding lines MN 139, MN 150, and Au 704, but not for ‘Colossus’. In vitro dry matter digestibility (IVDMD) was >63% for both stems and leaves in all cultivars and was not affected by plant population. Crude protein (CP) in leaves exceeded 20% for all treatments. We conclude that cowpea has excellent potential for supplying high-quality forage from double-cropping systems in the midwestern United States.
Abstract
Equal half-root systems of cowpea seedlings were achieved with a split-root technique. By use of a high humidity chamber and growth pouches, it was determined that the survival rate of seedlings with bisected root systems was greater than 95%, and the development of the half root systems was uniform and adequate. There were no marked differences in growth and development of plants when treatments were applied to different halves of the root system. However, there was evidence of Zn translocation from noninoculated half-root systems which received Zn, to inoculated half-roots not receiving Zn, which resulted in increased nodulation and N2 fixation. This result supports reports of a direct relationship of Zn nutrition to nodulation and N2 fixation.
Methods to improve the grain yield of red kidney bean without the addition of commercially fixed nitrogen will have significant benefits to farmers in Jamaica and other tropical regions. Red kidney beans provide a major portion of the dietary protein for most families in these regions. Our experimental objective was to evaluate the nitrogen fixing capabilities of several breeding lines of Phaseolus vulgaris when inoculated with Rhizobium strains isolated from Jamaican soils. Surface sterilized seeds of 11 Phaseolus lines were inoculated with inoculum prepared from 5 day old Rhizobium YEM mixture. Rhizobium used were T2 and B17 from Jamaica and UMR 1889. The greenhouse study was arranged as a completely randomized design. Bean lines 9056-101, 9056-98B, 8954-5 and 8954-4 showed improved nodulation and N2 fixation when inoculated with UMR 1899. The combination of breeding line 8954-5 and Rhizobium strain B17 produced the highest nodule number and shoot dry weight of 193 and 0.72 g, respectively. The Rhizobium strain B17showed some ability to compete successfully for nodule sites against known effective strains.
Home gardeners and farmers in the southern United States have traditionally grown southernpeas to produce both fresh-shell peas and immature, fresh pods, or snaps. American growers do not presently have access to a single variety that is ideally suited for both uses. In 1988, a plant breeding effort was initiated to incorporate genes conditioning superior yield and seed characteristics of Asian “vegetable cowpeas” into American snap-type southernpeas. This effort resulted in the development of `WhipperSnapper', which is suited for use as a dual-purpose variety that can be used to produce both snaps and fresh-shell peas. Typical ready-to-harvest `WhipperSnapper' snaps are green colored, 6.4 mm in diameter, 7.6 mm in height, and 24 cm long. Typical mature-green pods suitable for fresh-shell harvest exhibit an attractive yellow color, are 25 cm long, and contain 14 peas. Fresh peas are cream-colored, kidney-shaped, and weigh 24.5 g per 100 peas. Dry pods exhibit a light straw color, and the dry peas have a smooth seedcoat. The total `WhipperSnapper' yield of snaps can be as much as 62% greater than the total snap yield of the snap-type variety `Bettersnap'; pea yield can be as much as 69% greater. The quality of `WhipperSnapper' seed is excellent and much superior to that of `Bettersnap'. `WhipperSnapper' can be used by home gardeners and market gardeners to produce abundant quantities of snaps and fresh-shell peas during seasons too hot for successful culture of such table legumes as snap beans. `WhipperSnapper' also has the potential for use as a mechanically harvested source of snaps for use by food processors in mixed packs of peas and snaps.