Black-eyed Pea Research Articles

Interstrain pseudorecombinants of cowpea chlorotic mottle virus: effects on systemic spread and symptom formation in soybean and cowpea.

Full-length complementary DNA (cDNA) copies of genomic RNA1, RNA2, and RNA3 segments of cowpea chlorotic mottle virus (CCMV) strains D, N, and S were synthesized using polymerase chain reaction and were cloned downstream of a T7 RNA polymerase promoter. Mixtures of the homologous in vitro-transcribed RNAs produced typical CCMV symptoms when inoculated on soybean (cv. Bragg) and cowpea (cv. California Blackeye) plants. Using either gel-purified or in vitro-transcribed CCMV RNA components, the pseudorecombinants SSD, SSN, DDS, and NNS were constructed. The properties of these pseudorecombinants were tested by comparing the induced symptoms, virus concentration, and systemic spread. These studies revealed a direct involvement of RNA3 genetic information in necrotic lesion formation and in breakage of CCMV resistance in soybean. Exchanges between RNA1 or RNA2 components further affected the biological features of reassorted CCMV variants. The true nature of the pseudorecombinants was confirmed by reconstitution of the parental strains from the corresponding pseudorecombinant RNA components.

Occurrence, Distribution, and Pathogenicity of the Cowpea Root and Stem Rot Pathogen,Phytophthora vignae,in Soils of Sri Lanka

A Phytophthora sp. isolated from stem and root lesions of cowpeas (Vigna unguiculata subsp. unguiculata «California Blackeye») grown in a mixture of riverbank and forest soils in containers under greenhouse conditions was identified as P. vignae based on morphological characters and pathogenicity tests. P. vignae was isolated from soils in three of five cowpea-growing districts of Sri Lanka by baiting with plants of the susceptible cowpea cultivar California Blackeye or by floating disks of tea leaves over soil. However, the root and stem disease was apparent at only one site, suggesting that some field soils might be suppressive. Among the 25 field soils tested, the disease potential index varied from 0 in many fields to 16 in one field

Effect of the growth retardant LAB 198 999, an acylcyclohexanedione compound, on epicotyl elongation and metabolism of gibberellins A1 and A20 in cowpea

The effect of LAB 198 999 [3,5-dioxo-4-butyryl-cyclohexane carboxylic acid ethyl ester; a new plant growth retardant which competitively inhibits 2-oxoglutarate-dependent gibberellin (GA) dioxygenases] on elongation and in-vivo [(3)H]GA1 and [(3)H]GA20 metabolism in cowpea (Vigna sinensis L. cv Blackeye pea No. 5) epicotyls has been investigated. Gibberellins and LAB 198 999 were injected into the epicotyl at 25-30 mm from the apex. In intact seedlings, epicotyl elongation was inhibited by LAB 198 999 (25 μg · epicotyl(-1)), and the inhibition was counteracted by GA1 but not by GA20. In contrast to intact seedlings, the inhibitor enhanced epicotyl elongation in de-bladed seedlings and expiants, in the latter case proportionally to the amount of inhibitor applied (up to 50 μg · epicotyl(-1)), but not in explants made from paclobutrazol-treated seedlings. The inhibitor also enhanced dramatically the elongation induced in paclobutrazol-treated expiants by GA1, but not by GA20. The promotive effect of LAB 198 999 was associated with increased contents of GA1 and GA8 in the growing region of the epicotyl, indicating a dependence on endogenous GAs. The effect of LAB 198999 decreased progressively with the age of the seedlings, probably as a consequence of a decreased level of GAs in the epicotyl. Gibberellin substrates and metabolites in the growing region of the epicotyl (upper 20 mm) were fractionated and identified tentatively by high-performance liquid chromatography and radiocounting using a homogeneous on-line radioactivity detector. The metabolism of [(3)H]GA1(t) (tentative) to [(3)H]GA8(t), and that of [(3)H]GA20(t) to [(3)H]GA1(t) and [(3)H]GA29(t) in the epicotyl were blocked by LAB 198 999, that of the former more efficiently than the latter. The results presented support the hypothesis that GA1 is the active GA controlling elongation of cowpea epicotyls. They also show that both the promotion of epicotyl elongation in explants and the enhancement of the effect of exogenous GA1 by LAB 198 999 are the result of the inhibitor blocking the in-vivo 2β-hydroxylation of GA1.

PROCESSING and UTILIZATION of COWPEAS IN DEVELOPING COUNTRIES: A REVIEW

Cowpeas (Vigna unguiculata or Vigna sinensis), also known as blackeye beans or southern peas, are important grain legumes in Africa and other developing countries where they serve as good sources of protein, energy and other nutrients. Despite their potential in upgrading diets of the poor people of the world, there are certain constraints to optimal utilization of cowpeas as food. These are attributed to factors such as pest infestation of the beans, beany flavors, extended cooking times and presence of antinuthents that cause low digestibility and abdominal upsets. Methods of circumventing these constraints to cowpea utilization are outlined. the literature on various processing techniques such as milling, dehulling, soaking, germination, fermentation and heat treatment are reviewed, and popular ways of preparing cowpea foods are discussed. Utilization of cowpeas in both infant and adult foods is recommended in the preparation of traditional and novel products in order to avert the perennial problems of malnutrition in developing countries.

Stomatal response to short‐term osmotic stress of cowpea plants given varying phosphorus fertilization1

Abstract Cowpea (Vigna unguiculata [L.] Walp. ‘California Blackeye') plants were grown at seven rates of phosphorus (P) fertilization: 0.0 to 3.6 mM P provided weekly. When plants were eight weeks old, stomatal conductance (Cs) was measured before and after lowering soil water potential to ‐1.0 MPa with a sorbitol solution. Prestress Cs was between 4 and 5 mm/s in 0.0 to 2.4 P plants and varied between 5 and 7 mm/s in 3.0 and 3.6 P plants. Declines in Cs were similar after lowering of soil water potential in plants of all treatments except 0.6 P, which tended to have lower Cs.

Viral Genome Delivery into Detached and Intact Leaf Tissues of Vigna unguiculata by RNA-coated Gold Particles Using the Improved Particle Gun.

Successful delivery of genomic RNA of sweet clover necrotic mosaic virus to detached and intact leaf tissues of Vigna unguiculata cv. California Black Eye, has been demonstrated by using a simple biolistic device equipped with a polyacetal macroprojectile with RNA-coated gold particles, driven by gas pressure from a nitrogen cylinder controlled by a solenoid valve. The device is free of explosive heat and thus cell damage due to delivery operation is minimized.

Serological and biological relationships among viruses in the bean common mosaic virus subgroup.

Bean common mosaic virus (BCMV), blackeye cowpea mosaic virus (B1CMV), cowpea aphid-borne mosaic virus (CABMV), azuki bean mosaic virus (AzMV), and peanut stripe virus (PStV) are five species of the genus Potyvirus, family Potyviridae which are seed-transmitted in beans or cowpeas. Eighteen isolates of BCMV, five isolates of B1CMV, four isolates of CABMV, and one isolate each of AzMV, and PStV were compared serologically using a panel of 13 monoclonal antibodies (MAbs) raised against BCMV, B1CMV, CABMV, or PStV in indirect enzyme-linked immunosorbent assay (ELISA). Four MAbs detected all virus isolates; one detected all isolates except those of CABMV. Three MAbs were specific only for serotype A isolates of BCMV. Four MAbs detected all serotype B isolates of BCMV plus all isolates of B1CMV, AzMV, and PStV. None of the antibodies distinguished among these four viruses. However, in biological tests with 11 bean cultivars selected for differentiating BCMV pathotypes, all isolates of B1CMV, AzMV, and PStV could be differentiated from the BCMV serotype B isolates by their reactions on a few bean cultivars in host group I and the cowpea cultivar California Blackeye #5. Potential problems that can arise from the use of nonauthenticated isolates are also discussed.

Registration of ‘California Blackeye 88’ Cowpea

Crop ScienceVolume 31, Issue 6 cropsci1991.0011183X003100060074x p. 1703-1704 Registration of Cultivars Registration of ‘California Blackeye 88’ Cowpea D. Helms, Corresponding Author D. Helms n/a@.dne Dept. Agronomy and Range Science, University of California, Davis, CA, 95616Corresponding author.Search for more papers by this authorL. Panella, L. Panella Dept. Agronomy and Range Science, University of California, Davis, CA, 95616Search for more papers by this authorI. W. Buddenhagen, I. W. Buddenhagen Dept. Agronomy and Range Science, University of California, Davis, CA, 95616Search for more papers by this authorC. L. Tucker, C. L. Tucker Dept. Agronomy and Range Science, University of California, Davis, CA, 95616Search for more papers by this authorK. W. Foster, K. W. Foster Nor-Cal Wild Rice, P.O. Box 940, Woodland, CA, 95695Search for more papers by this authorP. L. Gepts, P. L. Gepts Dept. Agronomy and Range Science, University of California, Davis, CA, 95616Search for more papers by this author D. Helms, Corresponding Author D. Helms n/a@.dne Dept. Agronomy and Range Science, University of California, Davis, CA, 95616Corresponding author.Search for more papers by this authorL. Panella, L. Panella Dept. Agronomy and Range Science, University of California, Davis, CA, 95616Search for more papers by this authorI. W. Buddenhagen, I. W. Buddenhagen Dept. Agronomy and Range Science, University of California, Davis, CA, 95616Search for more papers by this authorC. L. Tucker, C. L. Tucker Dept. Agronomy and Range Science, University of California, Davis, CA, 95616Search for more papers by this authorK. W. Foster, K. W. Foster Nor-Cal Wild Rice, P.O. Box 940, Woodland, CA, 95695Search for more papers by this authorP. L. Gepts, P. L. Gepts Dept. Agronomy and Range Science, University of California, Davis, CA, 95616Search for more papers by this author First published: 01 November 1991 https://doi.org/10.2135/cropsci1991.0011183X003100060074xCitations: 7AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume31, Issue6November-December 1991Pages 1703-1704 RelatedInformation

Interactions between Fusarium oxysporum f. sp. racheiphilum and Meloidogyne spp. in Vigna unguculata. 2. Specificity of different taxa

A California isolate of Meloidogyne javanica increased Fusarium wilt symptoms in cowpea cultivars California Blackeye No. 3 (CB3) (resistant to wilt) and Grant (tolerant) inoculated with each of the three races of Fusarium oxysporum f. sp. tracheiphilum. The same isolate of M. javancia did not similarly increase wilt in wilt-resistant cultivar CB7977 inoculated with two isolates of race 3 of F. o. tracheiphilum. Six of seven isolates of M. javanica caused similar increases in vascular discoloration in cultivar CB3. but one isolate of M. javanica and seven of M. incognita did not. Vascular discoloration rating was positively correlated with galling severity. However, increasing the initial inoculum density, and thus galling index, of one isolate of M. incognita did not increase vascular discoloration. The vascular discoloration ratings for the wilt-susceptible CB5 controls in each experiment were higher than those for the wilt-resistant cultivars infected with M. javanica. It is hypothesized that M. javanica but not M. incognita reduces, but does not eliminate, resistance to all races of F. o. tracheiphilum in cultivars CB3 and Grant.

Interactions between Fusarium oxysporum f. sp. tracheiphilum and Meloidogyne spp. in Vigna unguiculata. 1. Effects of different inoculum densities on Fusarium wilt

The effects of chlamydosporesandconidia of Fusarium oxysporum f sp. tracheiphilum at different initial spore concentrations were compared in the wilt‐susceptible cowpea cultivar California Blackeye No. 5 (CB5). In glasshouse experiments with one inoculum density of either Meloidogyne incognita or M javanica, chlamydospores resulted in greater incidence and severity of Fusarium wilt than conidia at the same inoculum densities. Wilt symptoms also increased on wilt‐resistant cultivar CB3 as inoculum densities of M. javanica were increased. When three cultivars were infested with moderate or high densities of both F. o. tracheiphilum and M. javanica. only CB5 developed sere wilt at either inoculum density. The wilt‐tolerant cultivar Grant had mild wilt symptoms in most plants at moderate inoculum densities, and a tenfold increase in inoculum did not increase wilt ratings. CB3. however, had higher incidence and severity of Fusarium wilt symptoms at high inoculum densities, although 60% of the plants survived for 9 weeks.

Interactions between Fusarium oxysporum f. sp. tracheiphilum and Meloidogyne spp. in Vigna unguiculata. 3. Pathogenesis by F. o. tracheiphilum as affected by M. javanica and host cultivar

Experiments were conducted to determine the temporal and spatial effects of Meloidogyne jav anica and host cultivar on pathogenesis by Fusarium oxysporum f. sp tracheiphilum in cowpea. In the wilt-susceptible cowpea cultivar California Blackeye No. 5 (CB5). F. o. tracheiphilum proliferated rapidly in both the hypocotyl and first internode 6 weeks after inoculation. The fungus spread quickly upward as plants grew, colonized most tissues within 6 weeks, and caused severe wilt. In wilt-resistant cultivar CB3. there was little proliferation of F. oxysporum in any tissue, whether or not plants were infected by St. javanica. The fungus was found above the primary internode in 15”., of all CB3 plants, but did not continue to spread upward after 4 weeks Vascular discoloration was greatest when St. javanica was added 4 weeks before F. o. tracheiphilum, but simultaneous inoculation also increased wilt symptoms Root wounding did not increase wilt. Split-root experiments provided no evidence that infection by, M. javanica results in a translocatable factor that reduces wilt resistance. When hypocoivls were inoculated with F. o. tracheiphilum at different intervals after roots infected by St. jav anica were removed, there was no evidence that the effect of the nematode on wilt susceptibility was translocated or persistent.

Blackeye bean root rot diseases identified

Premature yellowing, aging and crop loss in blackeye bean is associated with root rot diseases caused by Fusarium solani and Thielaviopsis basicola. Now a new root rot disease caused by Phytophthora drechsleri could become a problem in wet soil.

Reproductive Abscission and Yield of Irrigated and Drought Stressed Cowpea

AbstractTwo experiments were conducted under field conditions to evaluate reproductive abscission, seed yield and yield components of three cowpea [Vigna unguiculata (L.) Walp.] genotypes. In the first experiment, level of abscission and yield of two cultivars, California Blackeye Pea No. 5 (CA‐5) and Speckle Purple Hull (SPH), and one experimental line (AZ‐54) were studied. In the second experiment, effect of drought stress on abscission at three nodal positions, seed yield, and yield components of CA‐5 were studied. Abscission in both experiments was determined by counting scars left by dropprd reproductive structures including floral buds, open flowers, and immature pods. Abscission of CA‐5 and AZ‐54 in the first experiment ranged between 68 and 76 % while that of SPH ranged between 86 and 89 %. CA‐5 and AZ‐54 retained two to three pods per peduncle, and SPH retained only one mature pod per peduncle. Average seed yields of SPH and AZ‐54, respectively, were 45 and 50 % of CA‐5. Drought stress in the second experiment did not affect production of floral buds Peduncle−1 (average of 10) but significantly increased percent reproductive abscission and decreased pod retention of CA‐5. Abscission in the bottom two‐third nodes increased from 82 % in well‐irrigated plants to 93 % in non‐irrigated plants. This increase in abscission corresponded to nearly 60 % reduction in pod retention. The number of pods per peduncle in the bottom two‐third nodes decreased from 1.9 in well‐irrigated plants to only. 77 in non‐irrigated plants. The increase in abscission and decrease in pod retention with increasing intensity of drought was greatest in the bottom one‐third nodes. Drought stress did not affect abscission and pod retention in the top one‐third nodes. Stress also decreased peduncles plant−1, seeds pod−1, and dry matter and seed yield plant−1 but did not affect seed weight and harvest index. The decrease in seed yield was largely due to reductions in pods plant−1 and seeds pod−1. The reduction in the number of pods and, therefore, seed yield due to stress was because of reductions in the number of peduncles plant−1 and increases in reproductive abscission. It is concluded external conditions that increase abscission beyond that of normal occurrence affect seed yield adversely.

Inheritance of Resistance to Blackeye Cowpea Mosaic Virus in White Acre-BVR' Cowpea

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.

Laboratory Evaluation of Toxicity of Calamus Oil Against Four Species of Stored-Product Insects2

Calamus oil, an essential oil of Acorus calamus L., was evaluated for its contact toxicity to adults of Callosobruchus maculatus (F.), Sitophilus oryzae (L.), Lasioderma serricorne (F.), and Tribolium confusum Jacquelin du Val. Topically applied, the oil was highly toxic to L. serricorne with 100% mortality at 30 μg/insect, and toxic to C. maculatus and S. oryzae with 98.3 and 61.7% mortality, respectively, at 50 μg/insect. It was nontoxic to T. confusum. When applied at a dosage of 1000 ppm to wheat or black-eyed peas, the oil completely protected them from infestation by S. oryzae and C. maculatus, respectively. The oil, at dosages of 500 and 250 ppm, still gave high protection to wheat and peas from infestation by these insects, respectively.

Toxicity and Repellency of Chenopodium Oil To Four Species of Stored-Product Insects2

Chenopodium oil, an essential oil of Chenopodium ambrosioides L., was evaluated for its toxicity and repellency to adults of Callosobruchus machulatus (F.), Sitophilus oryzae (L.), Lasioderma serricorne (F.), and Tribolium confusum Jacquelin du Val. Topically applied, the oil was highly toxic to C. maculatus (100% mortality at 40 μg/insect) and L. serricorne (92.5% mortality at 50 μg/insect), moderately toxic to S. oryzae (52.5% mortality at 50 μg/insect), and only slightly toxic to T. confusum at 50 μg/insect. When applied to the surface of wheat, the oil was highly repellent to S. oryzae. When applied to wheat or black-eyed peas, the oil reduced infestations of S. oryzae and C. maculatus at dosages of 2000 and 1000 ppm, respectively.

Host Range, Cytology, and Transmission of an Alyce-clover Isolate of Blackeye Cowpea Mosaic Virus

A blackeye cowpea mosaic virus (BlCMV) isolated from alyce-clover, designated as BlCMV-AC, was partially characterized. Cylindrical inclusions containing scrolls induced by BlCMV-AC were detected in infected plants by light, electron, and immunofluorescence microscopy. Isolate BlCMV-AC infected Alysicarpus vaginalis, Crotalaria spectabilis, Indigofera hirsuta, Lupinus albus, Macroptilium lathyroides, Nicotiana benthamiana, Phaseolus vulgaris «Black Turtle 2», Vigna unguiculata subsp. unguiculata «California Blackeye», Chenopodium amaranticolor, and C. quinoa (.)

Studies onBacillus thuringiensis H-14 strains isolated in Egypt?III. Selection of media for ?-endotoxin production

Several medium ingredients locally available in Egypt were investigated for their ability to support δ-endotoxin production by two mosquito-toxic strains ofBacillus thuringiensis H-14 usingCulex pipiens for the bioassay of δ-endotoxin. Soya beans, black-eyed beans, common peas and lentils supported good production of toxin whereas peanuts, fodder yeast, cheese whey and corn steep liquor gave only low amounts of toxin. Molasses as the sole carbon source at 2 and 3% (w/v) with soya (or Proflo) as the sole nitrogen source at 3% gave the best yields of toxin for strain M1 and S128 respectively.

Cultivar-specific induction of necrosis by exudates from basidiospore germlings of the cowpea rust fungus

Aqueous exudates from appressorium-bearing basidiospore germlings of race 1 of the cowpea rust fungus ( Uromyces vignae) elicited necrosis of mesophyll cells when injected into leaves of the resistant cowpea cv. Dixie Cream. Levels of necrosis were significantly higher than those elicited in a susceptible cultivar, California Blackeye, or in resistant cultivars, Queen Anne and Calico Crowder, that differ from Dixie Cream in their cytological responses to the fungus. Heating the exudates at 100 °C for 15 min destroyed the necrosis-eliciting activity. Exudates from a Nigerian isolate of the fungus to which all tested cultivars are susceptible elicited less necrosis in cv. Dixie Cream than exudates from race 1. The data suggest that basidiospore germlings of race 1 of the cowpea rust fungus secrete a cultivar-specific elicitor of plant necrosis.

YIELD POTENTIAL OF TWO COWPEA CULTIVARS GROWN FOR A CUT AND CARRY FORAGE SYSTEM IN MID-MISSOURI

The use of cowpea as a forage for Central Missouri has been limited. High mid summer temperatures and frequent drought suggest that an alternative forage for livestock may be advantageous during the hot summer months. The ability of cowpea to withstand drought, high temperature and maintain high foliage protein, justifies research of the forage potential of this crop. Forage yield potential of two cowpea cultivars was evaluated in field experiments in 1968 and 1989, For both years a split plot experimental design was utilized with cowpea cultivar the main plot and harvest date the subplot Dry matter yields for both cultivars were similar at the early harvest dates. However, both fresh and dry shoot yields of Vita 3 (V3) were significantly higher than that of California Blackeye #5 (CB #5) at the later harvest stages. CB #5 plants produced a significantly higher stem dry weight while V3 produced higher leaf dry matter. Foliage regrowth after clipping was substantial for both cowpea cultivars. However, V3 produced 30% higher growth than CB #5. In vitro dry matter digestibility (IVDDM) varied with sample date (plant age) and plant parts sampled. IVDDM was 77% for leaves and 60% for stems of CB#5, and 80% for leaves and 65% for stems of V3.