Reciprocal crosses were made between `White Acre-BVR', resistant to blackeye cowpea mosaic virus (BICMV), and the susceptible `California Blackeye No. 5' cowpea [Vigna unguiculata (L.) Walp.]. Seedlings from `California Blackeye No. 5', `White Acre-BVR', F1, F2, and backcrosses were mechanically inoculated with BICMV, and evaluated 4 weeks later for symptom expression in the greenhouse. Plants were assayed by enzyme-linked immunosorbent assay. The resistance observed in the F1 and progeny from the backcross to the resistant parent indicated that resistance to BICMV in `White Acre-BVR' was dominant. Furthermore, a 1 resistant: 1 susceptible segregation of progeny from the backcross to the susceptible parent and a 3 resistant: 1 susceptible segregation of the F2 progenies suggested that the resistance to BICMV in `White Acre-BVR' was conferred by a single dominant gene.
Sohedjie Ouattara and Oyette L. Chambliss
A.G. Hunter, O.L. Chambliss and J.C. Williams
Four southernpea (cowpea) [Vigna unguiculata (L.) Walp.] cultivars representing various combinations of resistance and susceptibility to blackeye cowpea mosaic virus (BlCMV) and southern root-knot nematode [Meloidogyne incognita (Kofoid and White) Chitwood] were used to determine effectiveness of simultaneous screening of plants for resistance to both pathogens. Plants were inoculated with both pathogens simultaneously, each pathogen separately, or left uninoculated as controls. The resistance classification of the cultivars based on treatments with only one pathogen was not different from that based on the treatment with both pathogens. Virus × nematode interaction was not a significant source of variation in BlCMV symptoms and root-knot nematode galls. Simultaneous screening for both pathogens in southernpeas appears to be a feasible option.
Richard L. Fery
The USDA has released a new, pinkeye-type southernpea cultivar that is homozygous for the gc gene conditioning the green cotyledon trait. The new cultivar, `Charleston Greenpack', can be harvested at the near-dry stage of pod maturity without loss of the pea's fresh green color. `Charleston Greenpack' originated as a bulk of an F8 [`Kiawah' × (`Kiawah' × `Bettergreen')] population grown in 1994. Except for the green seed color, a tendency for a slightly greener foliage, and a slightly smaller pea size, the phenotype of `Charleston Greenpack' is quite similar to those of `Coronet' and `Pinkeye Purple Hull-BVR'. The results of replicated field tests indicate that `Charleston Greenpack' yields are comparable to those of `Coronet' and `Pinkeye Purple Hull-BVR'. Results of raw product evaluations conducted at a commercial freezing facility indicate that `Charleston Greenpack' produces an excellent processed product. `Charleston Greenpack' has excellent field resistance to blackeye cowpea mosaic virus, the major pathogen of southernpea in the United States.
A.S. Kline and E.J. Anderson
the manuscript, and R. W. McNew for assistance with statistical analysis of data. This research was supported in part by grants from the cowpea and seed processing industries. The cost of publishing this paper was defrayed in part by the payment of
Richard L. Fery, Judy A. Thies and A. Graves Gillaspie
Ricardo Goenaga, Adolfo Quiles and A. Graves Gillaspie
the potyvirus Blackeye cowpea mosaic virus (BlCMV). BlCMV is regarded as a distinct strain of Bean common mosaic virus ( ICTV, 2002 ). The accession GC-86L-98 (PI 612607) is a germplasm line with resistance to CMV and high resistance to BlCMV
Richard O. Hampton
National Cowpea Improvement Assn.
A.G. Hunter, G.E. Boyhan, E.H. Simonne and O.L. Chambliss
National Cowpea Improvement Association
Muhammad Bashir and Richard Hampton
Sweetpotato Collaborators & Cowpea Meeting
Oyette L. Chambliss, Arthur G. Hunter and Richard O. Hampton
Germplasm accessions and advanced lines were evaluated for seed transmission of the seed borne viruses, cucumber mosaic (CMV), cowpea severe mosaic (CSMV), and blackeye cowpea mosaic (B1CMV). Seed samples from 822 field plots (274 out of 300 accessions in 3 replications) which had been evaluated for insect resistance in 1992 were planted in the greenhouse. Mosaic virus symptoms had been apparent throughout the 1992 field planting. Evaluation for mosaic symptoms was done at the seedling stage in the greenhouse and 89 entries exhibited seed borne virus symptoms in one or more plants. Of these, 78 were shown by ELISA (enzyme linked immunosorbant assay, direct antigen coating method) to contain at least one of the seed borne viruses for which we were evaluating.