Leaves are smooth, dull to shiny, and rarely pubescent. Commonly, the terminal leaflet is longer and larger than the lateral leaflets. There is a wide range in leaf size and shape. Cowpea generally is day neutral. Flowers are borne in multiple racemes on 8 to 20 in. Two or three pods per peduncle are common and often four or more pods are carried on a single peduncle.
The presence of these long peduncles is a distinguishing feature of cowpea and this characteristic also facilitates harvest. The open display of flowers above the foliage and the presence of floral nectaries contribute to the attraction of insects.
Cowpea primarily is self pollinating. Cowpea pods are smooth, 6 to 10 in. As the seeds approach the green-mature stage for use as a vegetable, pod color may be distinctive, most commonly green. As the seeds dry, pod color of the green and yellow types becomes tan or brown. Cowpea is a warm-season crop well adapted to many areas of the humid tropics and temperate zones. It tolerates heat and dry conditions, but is intolerant of frost.
Cowpeas are grown under both irrigated and non-irrigated regimes. The crop responds positively to irrigation but will also produce well under dryland conditions. Cowpea is more drought resistant than common bean. Drought resistance is one reason that cowpea is such an important crop in many underdeveloped parts of the world.
If irrigation is used, more vegetative growth and some delay in maturity may result. Application rates should insure that the crop is not overwatered, especially in more northern latitudes, as this will suppress growth by lowering soil temperatures. The most critical moisture requiring period is just prior to and during bloom. Cowpea performs well on a wide variety of soils and soil conditions, but performs best on well-drained sandy loams or sandy soils where soil pH is in the range of 5.
Soils should be cultivated deeply enough to insure that no barrier to penetration of the soil by the taproot such as a hardpan exists. Cowpea may be adversely affected by soil crusting under certain soil and environmental conditions.
Seeds will decay in cool, wet soils. In the Minnesota-Wisconsin area, optimum seeding dates usually correspond to those for fieldbean May Traditionally, cowpea in the United States has been seeded in rows spaced 30 to 36 in. Recently, higher plant populations achieved by using narrow rows 12 to 20 in. For forage purposes, the crop may be seeded in rows or broadcast solid-seeded. The amount of seed to sow per acre depends on seed weight, germination percentage, and plant spacing.
Optimum plant spacing depends on vine type. Highly determinate types may be planted 2 to 3 in. Viney indeterminate types require more space, and a final stand with 8 to 9 in. Cowpea, like all legumes, forms a symbiotic relationship with a specific soil bacterium Rhizobium spp. Rhizobium makes atmospheric nitrogen available to the plant by a process called nitrogen fixation. Fixation occurs in root nodules of the plant and the bacteria utilize sugars produced by the plant.
Although cowpea Rhizobium is normally widespread, seed inoculation with Rhizobium specific to cowpea would be beneficial in areas where it is not present. Always use Rhizobium of the cowpea type. Excess nitrogen N promotes lush vegetative growth, delays maturity, may reduce seed yield and may suppress nitrogen fixation.
The plant will perform well under low N conditions due to a high capacity for N fixation. A soil test is the best way to determine soil nutrient levels. Band fertilizer 3 to 4 in. The Institute has developed high yielding, short season, multiple disease-resistant varieties that are ready for harvest in 60 days. Several of the U. State Agricultural Experiment Stations conduct cowpea variety development programs.
Crude protein and digestibility of the whole plant are reported to be similar to alfalfa with yields ranging from 1. Table 2. Dry-matter yields of cowpea cultivars and breeding Hues grown under two plant populations in and at Becker and Waseca, Minnesota.
The shelled peas are attractive, mild flavored and suitable for processing. The white hilum is surrounded by black, pink, or light-red. The immature seeds, when cooked, are a medium to dark brown color, very tender, and have a delicate flavor. They are no longer commonly grown.
This type is a semi-crowder, generally tan in color and somewhat small. Pods are quite stiff. Table 3. Days to harvest, seed type, seed yield-, and canopy size of cowpea cultivars on an irrigated sandy loam, Becker, Minn. Rows were spaced 30 in. Pods were air-dried for 2 months before threshing and weighing. Mechanical: Use of the rotary hoe and row cultivator in cowpea is similar to that of soybean.
One or two rotary hoeings followed by timely cultivation should be done when no herbicides are used. One or more cultivations should also be done when herbicides are used. Chemical: The term " cowpea" is not found on most herbicide labels. Rather, the crop is referred to as blackeyed peas, southern peas, pinkeyed peas or crowder peas.
Farmers planning on producing cowpeas should check with their State Agricultural Extension Service for advice on chemical weed control. Root rot and damping off are caused by three different fungi. Symptoms vary and include rapid death of young succulent plants, discoloration of taproots, longitudinal cracks of the stems, stunting, wilting and poor yields. Bacterial blight is an important Roberts et al.
Thus Rk may be a complex disease in the southeastern US, and sources of resis- nematode resistance locus, analogous to those re- tance are known, but little progress has been made in ported for other plant pathogen-host combinations incorporating resistance to this disease into commer- Roberts et al.
This resistance is being incor- cial cultivars Patel, Resistance to parasitic weeds 5. Multiple pest and disease resistance The parasitic weeds Striga gesnerioides Wild. Until recently, the focus of many cowpea im- Vatke and Alectra vogelii Benth. Breeders lacked an ar- Savanna, respectively. Several sources of resistance ray of well adapted pest and disease resistant parental to these parasites have been identified and the resis- lines that could be recombined to generate cultivars tance has been incorporated into advanced breeding with multiple resistances.
Genetic studies have In California, the immediate challenge is to de- shown that three dominant, nonallelic genes confer velop cultivars that combine resistance to several resistance to different striga biotypes but that the races of two species of root-knot nematodes, two mechanisms differ Singh, A different set of races of fusarium wilt, cowpea aphid, a disease that three dominant, nonallelic genes have been identified causes early senescence Erwin et al.
Accession tolerance to heat. These traits now exist individually, B is an important source of resistance to both or in some cases doubly in elite backgrounds, but no striga and alectra, but has extremely poor agronomic single elite line has all of the desired traits. A similar situation exists in Senegal where culti- vars and advanced breeding lines have been devel- 5. Resistance to nematodes oped that collectively have resistance to aphids, cow- pea weevil, striga, CABMV, and bacterial blight but Root-knot nematode resistance in cowpea was no one line has all of these resistance traits.
Seed characteristics 'Mississippi Silver', and 'Colossus' have been de- veloped. Virtually all these cultivars rely on the Rk Cowpea exhibits a range of individual seed weight gene, which provides protection against a broad from slightly less than mg seed -1 up to nearly spectrum of Meloidogyne species.
Transfer of the all-white because most progeny from crosses have smaller trait is relatively easy because this trait segregates as seed. Smooth seed coats are preferred in East Africa a single recessive factor in crosses with blackeye while rough or wrinkled seed coats are preferred in seeded lines, and can be scored before flowering most areas of West Africa because the seedcoat is because plants exhibiting all-white seed lack the easily removed following brief soaking in water.
Cowpea used primarily for 5. Breeding for plant morphological and phenolog- forage typically have small seed to mg ical characteristics seed- 1. Cowpea cultivars differ in nutritional composition Cowpea exhibits a wide range of plant habits, and cooking characteristics.
Seed protein of flowering times, and maturities. For these same breeding lines, fat content the basic plant size and shape Ehlers, Plant- ranged from 1. These results suggest perature, availability of moisture, and other environ- that there is sufficient genetic variability for breeders mental factors also influence plant development, and to develop cultivars with high protein content which affect the shape and size of the plant and canopy.
Furthermore, plant architecture varies widely by lo- Production of cowpea with grain types that suit cation and planting date if photoperiod sensitivity is specific local preferences can limit domestic trade present. Cultivars that are early and erect in short-day and export opportunities if the preferred type is not environments may be significantly delayed in flower- desirable in other regions.
Development of cultivars ing in long-day environments and exhibit a prostrate with widely accepted seed characteristics could be growth habit. These that have large white grain with a black pigmented categories are generally useful to breeders and area the eye around the hilum.
Large, all-white agronomists, but only are valid for specific climatic cowpea seed with a rough seed coat is widely ac- zones and are imprecise in that they do not denote cepted for direct human consumption, and would be determinacy, extent of branching and internode elon- acceptable to industry if all-white seed produces a gation, and angle of branching.
It would be useful to more useful flour after grinding McWatters, Cowpea is used basic plant types are defined based on type of stem in the production of value-added foods such as cow- termination and branching pattern. As a general rule, pea flour for traditional dishes such as akara, moin- early-erect determinate culfivars may not be effective moin, weaning foods, extruded snack items, cowpea in production zones where midseason stresses, such 'rice' and cowpea 'couscous'.
Medium-cycle, spreading Large-seeded, all-white breeding lines with rough types may be more effective in these zones. In higher density inter- vation of lowland rice Oryza sativa L. Develop- cropping systems, early-erect breeding lines have ment of day-neutral cultivars that are widely adapted performed well Singh et al. Erect types are needed for for almost 50 years.
Synchronous flow- yet commercial cultivars produce their first flush of ering and maturity are other attributes that are useful pods in 80 to 90 days. A significant number of in intensive mechanized cowpea production because growers continue to irrigate their crops for an addi- simultaneous pod maturity facilitates efficient tional 30 to 60 days and can obtain very high yields 'once-over' harvesting Fery, In contrast, se- if the crop does not senescence after the first flush of quential flowering and fruiting is useful in develop- pods is produced Hall and Frate, This early ing countries because fresh pods are available over a senescence is caused by a complex of soil pathogens long period of time and such cultivars can have aggravated by plant stress Erwin et al.
The greater tolerance of midseason stresses than syn- delayed leaf senescence DLS trait prevents early chronous flowering cultivars. This trait has accessions are photoperiod sensitive Ehlers and Hall, been incorporated into advanced lines which look ; Craufurd et al. For some genotypes, promising in replicated yield tests. Development of the degree of sensitivity to photoperiod extent of later flowering cultivars would be another approach delay in flowering is modified by temperature Wein to better utilize the available growing season.
Geno- and Summerfield, ; Ehlers and Hall, In typic differences in onset of reproductive develop- West Africa, selection for differing degrees of photo- ment juvenility of about 14 days have been ob- sensitivity or differences in juvenility has occurred in served among California breeding lines and other different climatic zones such that pod ripening coin- accessions evaluated for this trait Ehlers and Hall, cides with the end of the rainy season in a given and presumably this lateness could be trans- locale, regardless of the planting date, which must be ferred to adapted genotypes.
This attribute allows pods to escape 5. Drought adaptation damage from excessive moisture and from pathogens. Photoperiod sensitivity when appropriately deployed Physiological aspects of breeding for adaptation in a breeding program can be valuable to ensure crop to drought in cowpea have been reviewed recently maturity after wet seasons or before drought or cold Hall et al.
Selection for early flowering and weather limits crop growth. However, it may con- empirical yield testing of breeding lines under dry strain the direct usefulness of an otherwise desirable production conditions have been successfully used to cultivar to a small area of adaptation or even to a develop cowpea cultivars adapted to low rainfall specific season within this restricted area.
Because of areas of the Sahel Hall and Patel, ; Cisse et al. The main feature of this tion zones. Cultivars with environments in the Imperial and Coachella Valleys DLS also have enhanced production of forage be- of California and selecting for flowering and pod- cause their leaves remain green and attached to the ding intensity Hall, While heat tolerant lines, plant until harvest.
This trait can be readily manipu- exhibit markedly improved pod set they also suffer lated by breeding and is expressed in both California significant reductions in number of seeds per pod and Senegal Hall et al. Cultivars that flower under high temperature conditions Ehlers and Hall, early, possess the DLS trait, and have an indetermi- ; Ismail and Hall, Preliminary screening nate growth habit should exhibit drought adaptation of 56 genotypes revealed two accessions, TN and yield stability in many environments.
Early from Niger, and Vita 1 from Nigeria, which had no flowering is useful in years when the rainy season is reductions in numbers of seeds per pod under very short, allowing the production of some food when hot temperatures. Chilling tolerance recover when rainfall resumes. Increased chill- vars can resume vegetative and reproductive growth ing tolerance at emergence would be valuable in more quickly once moisture stress is alleviated.
Heat tolerance season. Also, in subtropical California, cowpeas that are sown early and exhibit adequate emergence usu- Breeding for heat tolerance was recently reviewed ally have greater grain yields than cowpeas that are Hall, with many specific examples from cow- sown late.
Chilling tolerance could also be useful in pea. Genotypic variation for two of Cameroon, and in cool-season production of cowpea the primary processes disrupted by heat, develop- at low elevation tropical areas such as along the river ment of floral buds and pollination, has been de- Niger, in the Senegal river basin, and near Lake scribed Warrag and Hall, ; Patel and Hall, Chad Ntare and Williams, Heat-tolerant large-seeded blackeye germplasm has been developed Hall, that is 5.
Harvesting efficiency effective in both long-day and short-day conditions Ehlers and Hall, In California, cowpeas whereas the ability to set pods under hot conditions are presently harvested in a three-step process in- is controlled by a single dominant gene Marfo and volving: 1 cutting the crop at ground level with a Hall, Heat tolerant breeding lines developed tractor mounted cutter, 2 windrowing, and 3 at the University of California, Riverside have pro- threshing the crop with a tractor pulled thresher after duced more than twice the yield of commercial drying in the field for about two weeks Hall and cultivars in two years of field trials conducted in the Frate, Direct-combining with grain combines Coachella Valley of California during the summer has been attempted but present cultivars are not well season, a very hot environment in the low-elevation suited as their thick stems resist drying and require desert Ismail and Hall, Population improve- Genetic variability exists in cowpea to create ment methods such as recurrent selection are useful direct-combine type cowpeas.
Our design for a culti- for longer term objectives such as incorporating mul- var and management methods effective for direct- tiple desirable traits into lines, in incorporating ex- combining is: 1 an erect plant type which resists otic germplasm into programs, and to improve insect lodging, and has pods held uniformly high but within or disease resistance in cases where only low to the canopy; 2 a seed that resists damage at thresh- moderate levels of insect resistance has been identi- ing due to its round shape and small air-gap between fied.
An effective form of recurrent selection for the cotyledons and 3 high density sowing in narrow combining multiple desirable traits consists of devel- rows to promote the development of thin stems. The oping sets of early generation F 3 or F4 inbred lines small air-gap trait can be selected by choosing seed from different biparental crosses, screening these to with high density, a highly heritable trait Robertson, identify individuals or lines with the desired new , which can be readily measured Wessel- combination of traits, and crossing these selected Beaver et al.
Design of the complete breeding program and conducting a further round of selection to incor- porate desirable features from all four parental lines. Standard breeding methods applicable to self-pol- Practical yet creative designs and approaches are linated crops for the development of pure-line culti- required to maximize the usefulness of the limited vars are commonly used in cowpea improvement and resources devoted to cowpea improvement.
Programs their use in cowpea breeding has been recently re- in Africa are particularly limited in infrastructure and viewed Hall et al. The diversity of biotic monetary resources but may have relatively abundant and abiotic environments and cropping systems in human labor available and multiple generations can which cowpea is grown, together with the particular be grown each year in the field if irrigation is uses made of the crop and the amount and type of available.
This type of program can be effective if it resources available to the program will dictate the has a large well-managed empirical field evaluation optimal design of the complete breeding program program, and progress can be rapid if three or four serving a particular region.
Most breeding programs generations are grown per year. Specialized field should use multiple methods for different breeding nurseries can be implemented at low cost to screen objectives each of which in turn will have a different for specific traits.
For example, a screening nursery expected time-frame for development of an im- can be planted late without insect protection to sub- proved cultivar.
For example, a newly organized ject breeding lines or accessions to uniformly high cowpea breeding program might have three compo- populations of insect pests. Early planting of disease- nents to meet short, medium, and long term goals.
Locations with regularly occurring draces, backcrossing especially for transfer of sim- and high pest pressure can be identified and used for ply inherited traits , and possibly mutation breeding pest resistance screening.
These Yield evaluations must be conducted in environ- methods require relatively little time to obtain fixed ments and cropping systems that are representative lines and because these new lines will closely resem- of the region being served by the program Ehlers, ble one of parental cultivars for most agronomic Cowpea researchers in Africa have often con- traits, only a limited number of years of field testing ducted yield evaluations under insecticide protected, would generally be required prior to release.
This can discourage farmers tions should be conducted under the predominant from allocating more land to cowpea production or systems being served by the breeding program al- from intensifying their cowpea production system in though unprotected sole-crops may be used in early future years.
An increased level of cowpea weevil generation breeding nurseries Ntare et al. Each year, seeds In the US, total production of cowpea for dry of promising new breeding lines developed at IITA grain has remained relatively constant over the last are formulated into several types of pre-packaged several decades, even with large increases in produc- yield trials in the form of 'Cowpea International tivity Hall and Frate, Demand for cowpea Trials' and made available to cowpea researchers in appears to be relatively constant and a moderate 50 countries worldwide Singh, The lines in increase in production depresses prices Hall and these trials and others made available from IITA are Frate, The demand for cowpea could be en- a valuable resource both as potential cultivars and as hanced in the US by marketing efforts to popularize improved parents for crossing.
Future prospects Insect resistant cowpeas would dramatically in- crease cowpea productivity in many developing Breeders and agronomists must be familiar with countries and reduce costs, safety hazards, and envi- existing local farming practices, systems constraints, ronmental risks in these and in other countries.
High and preferences for grain, pod, leaf, or forage qual- levels of resistance to the major insect pests, espe- ity. They must also look forward and predict likely cially flower thrips and pod sucking bugs, have not changes in these factors and initiate long term breed- been identified in the cultivated cowpea genepool, ing efforts to accommodate these projected changes. Introgression of insect resis- Africa if this region is to avoid increasing poverty tance traits from wild cowpeas and efforts to hy- and dependence on food imports and further environ- bridize cowpea with related Vigna species should be mental degradation.
This implies that cowpea culti- pursued vigorously. Improved hay and dual- ers with effective insect resistance genes in the near purpose cultivars are needed for some regions where future. The transformed genotypes are likely to be livestock are important Tarawali et al. As an adapted to only a few regions, but will be useful efficient nitrogen fixing legume, cowpea could have parents for breeding programs.
Therefore, cowpea an increasingly important role in maintenance of soil breeders need to stay abreast of recent developments fertility in this region.
They should obtain newly Rapidly growing urban populations of cowpea transformed insect-resistant genotypes as soon as consumers in sub-Saharan Africa and other countries possible so they can begin to evaluate these geno- of the world should provide strong markets for this types for effectiveness under their conditions.
If the crop in the future. In many developing countries, insect resistance is effective, they should incorporate local production excesses can occur which when it into cultivars suitable for their region of responsi- combined with the lack of effective on-farm storage bility. Perrino, F. Attere and H. C o w p e a is a relatively unex- Africa, Vol. II, pp. Bata, H. Crop Sci. Genetic diversity in Vigna. Singh and K. Rachie, Cowpea Research, greatly i n c r e a s e d understanding o f c o w p e a , particu- Production and Utilization.
Wiley, New York, pp. Blade, S. Singh and M. Raj, Advances in Cowpea Re- and n e m a t o d e s , and genetic resources. Nutritive value of cowpea. In: eds. Singh lines that p r o v i d e a strong basis for future crop and K. Rachie, Cowpea Research, Production and Utiliza- tion.
T h e i n c r e a s e d understanding o f Chambliss, O. Green seedcoat: a mutant in southempea the crop, the avaiiability o f i m p r o v e d g e r m p l a s m , of value to the processing industry.
Genegreen: a unique southernpea variety released by AAES. Highlights of Agricul- tion' for this crop in Africa. Chambliss, O. Vigna unguiculata germplasm evaluated for resistance to insects. Acknowledgements Singh and M.
Raj, Advances in Cowpea Research. Cisse, N. Registra- tion of 'Mouride' cowpea. R e s e a r c h that contributed to this r e v i e w was par- Cisse, N. Photoperiod, temperature, and the growth and develop- ment of cowpea. The opinions and r e c o m - Cowpea Research. Daoust, R. Distribu- tion, biology and control of cowpea pests in Latin America. References In: eds. Rachie, Cowpea Research, Production and Utilization.
Abadassi, J. Davis, D. MN13 and and Emechebe, A. Inheritance of resistance to brown MN cowpea breeding lines. Assessment and utilization of exotic cowpea lata L.
Indian J. Adebitan, S. PhD Diss. California, Davis. Use of three inoculation methods in screening cowpea geno- Ehlers, J. Correlation of performance of sole-crop and types for resistance to two Colletotrichum species. Plant Dis. Field Crops Res. Ahmed, F.
Heat injury Ehlers, J. Introgression of agronomic during floral bud development in cowpea Vigna unguiculata, characters from exotic cowpea germplasm into blackeye bean. Ashraf, M. Farming systems approach: Research on cow- Ehlers, J. Genotypic classification of peas and extension. Rachie, cowpea based on responses to heat and photoperiod. Wiley, New York, pp. Ehlers, V. Heat tolerance of contrasting Barone, A. Embryological study of crosses cowpea lines in short and long days.
Ng, press. Heat tolerance during flower- Cowpea Research, Production and Utilization. Wiley, New ing and heat and chilling tolerance dtLdng germination are not York, pp. Hall, A. Cowpea breeding. Elowad, H. Influences of early and late Plant Breeding Reviews Vol. In: Emechebe, A. Shoot and pod diseases Hampton, R. Genotypic variation for two of Cameroon, and in cool-season production of cowpea the primary processes disrupted by heat, develop- at low elevation tropical areas such as along the river ment of floral buds and pollination, has been de- Niger, in the Senegal river basin, and near Lake scribed Warrag and Hall, ; Patel and Hall, Chad Ntare and Williams, Heat-tolerant large-seeded blackeye germplasm has been developed Hall, that is 5.
Harvesting efficiency effective in both long-day and short-day conditions Ehlers and Hall, In California, cowpeas whereas the ability to set pods under hot conditions are presently harvested in a three-step process in- is controlled by a single dominant gene Marfo and volving: 1 cutting the crop at ground level with a Hall, Heat tolerant breeding lines developed tractor mounted cutter, 2 windrowing, and 3 at the University of California, Riverside have pro- threshing the crop with a tractor pulled thresher after duced more than twice the yield of commercial drying in the field for about two weeks Hall and cultivars in two years of field trials conducted in the Frate, Direct-combining with grain combines Coachella Valley of California during the summer has been attempted but present cultivars are not well season, a very hot environment in the low-elevation suited as their thick stems resist drying and require desert Ismail and Hall, Population improve- Genetic variability exists in cowpea to create ment methods such as recurrent selection are useful direct-combine type cowpeas.
Our design for a culti- for longer term objectives such as incorporating mul- var and management methods effective for direct- tiple desirable traits into lines, in incorporating ex- combining is: 1 an erect plant type which resists otic germplasm into programs, and to improve insect lodging, and has pods held uniformly high but within or disease resistance in cases where only low to the canopy; 2 a seed that resists damage at thresh- moderate levels of insect resistance has been identi- ing due to its round shape and small air-gap between fied.
An effective form of recurrent selection for the cotyledons and 3 high density sowing in narrow combining multiple desirable traits consists of devel- rows to promote the development of thin stems. The oping sets of early generation F 3 or F4 inbred lines small air-gap trait can be selected by choosing seed from different biparental crosses, screening these to with high density, a highly heritable trait Robertson, identify individuals or lines with the desired new , which can be readily measured Wessel- combination of traits, and crossing these selected Beaver et al.
Design of the complete breeding program and conducting a further round of selection to incor- porate desirable features from all four parental lines. Standard breeding methods applicable to self-pol- Practical yet creative designs and approaches are linated crops for the development of pure-line culti- required to maximize the usefulness of the limited vars are commonly used in cowpea improvement and resources devoted to cowpea improvement.
Programs their use in cowpea breeding has been recently re- in Africa are particularly limited in infrastructure and viewed Hall et al.
The diversity of biotic monetary resources but may have relatively abundant and abiotic environments and cropping systems in human labor available and multiple generations can which cowpea is grown, together with the particular be grown each year in the field if irrigation is uses made of the crop and the amount and type of available.
This type of program can be effective if it resources available to the program will dictate the has a large well-managed empirical field evaluation optimal design of the complete breeding program program, and progress can be rapid if three or four serving a particular region. Most breeding programs generations are grown per year. Specialized field should use multiple methods for different breeding nurseries can be implemented at low cost to screen objectives each of which in turn will have a different for specific traits.
For example, a screening nursery expected time-frame for development of an im- can be planted late without insect protection to sub- proved cultivar. For example, a newly organized ject breeding lines or accessions to uniformly high cowpea breeding program might have three compo- populations of insect pests. Early planting of disease- nents to meet short, medium, and long term goals. Locations with regularly occurring draces, backcrossing especially for transfer of sim- and high pest pressure can be identified and used for ply inherited traits , and possibly mutation breeding pest resistance screening.
These Yield evaluations must be conducted in environ- methods require relatively little time to obtain fixed ments and cropping systems that are representative lines and because these new lines will closely resem- of the region being served by the program Ehlers, ble one of parental cultivars for most agronomic Cowpea researchers in Africa have often con- traits, only a limited number of years of field testing ducted yield evaluations under insecticide protected, would generally be required prior to release.
This can discourage farmers tions should be conducted under the predominant from allocating more land to cowpea production or systems being served by the breeding program al- from intensifying their cowpea production system in though unprotected sole-crops may be used in early future years.
An increased level of cowpea weevil generation breeding nurseries Ntare et al. Each year, seeds In the US, total production of cowpea for dry of promising new breeding lines developed at IITA grain has remained relatively constant over the last are formulated into several types of pre-packaged several decades, even with large increases in produc- yield trials in the form of 'Cowpea International tivity Hall and Frate, Demand for cowpea Trials' and made available to cowpea researchers in appears to be relatively constant and a moderate 50 countries worldwide Singh, The lines in increase in production depresses prices Hall and these trials and others made available from IITA are Frate, The demand for cowpea could be en- a valuable resource both as potential cultivars and as hanced in the US by marketing efforts to popularize improved parents for crossing.
Future prospects Insect resistant cowpeas would dramatically in- crease cowpea productivity in many developing Breeders and agronomists must be familiar with countries and reduce costs, safety hazards, and envi- existing local farming practices, systems constraints, ronmental risks in these and in other countries. High and preferences for grain, pod, leaf, or forage qual- levels of resistance to the major insect pests, espe- ity.
They must also look forward and predict likely cially flower thrips and pod sucking bugs, have not changes in these factors and initiate long term breed- been identified in the cultivated cowpea genepool, ing efforts to accommodate these projected changes.
Introgression of insect resis- Africa if this region is to avoid increasing poverty tance traits from wild cowpeas and efforts to hy- and dependence on food imports and further environ- bridize cowpea with related Vigna species should be mental degradation.
This implies that cowpea culti- pursued vigorously. Improved hay and dual- ers with effective insect resistance genes in the near purpose cultivars are needed for some regions where future. The transformed genotypes are likely to be livestock are important Tarawali et al.
As an adapted to only a few regions, but will be useful efficient nitrogen fixing legume, cowpea could have parents for breeding programs. Therefore, cowpea an increasingly important role in maintenance of soil breeders need to stay abreast of recent developments fertility in this region.
They should obtain newly Rapidly growing urban populations of cowpea transformed insect-resistant genotypes as soon as consumers in sub-Saharan Africa and other countries possible so they can begin to evaluate these geno- of the world should provide strong markets for this types for effectiveness under their conditions.
If the crop in the future. In many developing countries, insect resistance is effective, they should incorporate local production excesses can occur which when it into cultivars suitable for their region of responsi- combined with the lack of effective on-farm storage bility.
Perrino, F. Attere and H. C o w p e a is a relatively unex- Africa, Vol. II, pp. Bata, H. Crop Sci. Genetic diversity in Vigna.
Singh and K. Rachie, Cowpea Research, greatly i n c r e a s e d understanding o f c o w p e a , particu- Production and Utilization.
Wiley, New York, pp. Blade, S. Singh and M. Raj, Advances in Cowpea Re- and n e m a t o d e s , and genetic resources. Nutritive value of cowpea. In: eds. Singh lines that p r o v i d e a strong basis for future crop and K. Rachie, Cowpea Research, Production and Utiliza- tion. T h e i n c r e a s e d understanding o f Chambliss, O. Green seedcoat: a mutant in southempea the crop, the avaiiability o f i m p r o v e d g e r m p l a s m , of value to the processing industry.
Genegreen: a unique southernpea variety released by AAES. Highlights of Agricul- tion' for this crop in Africa. Chambliss, O. Vigna unguiculata germplasm evaluated for resistance to insects. Acknowledgements Singh and M. Raj, Advances in Cowpea Research.
Cisse, N. Registra- tion of 'Mouride' cowpea. R e s e a r c h that contributed to this r e v i e w was par- Cisse, N. Photoperiod, temperature, and the growth and develop- ment of cowpea. The opinions and r e c o m - Cowpea Research. Daoust, R. Distribu- tion, biology and control of cowpea pests in Latin America.
References In: eds. Rachie, Cowpea Research, Production and Utilization. Abadassi, J. Davis, D. MN13 and and Emechebe, A. Inheritance of resistance to brown MN cowpea breeding lines. Assessment and utilization of exotic cowpea lata L. Indian J. Adebitan, S. PhD Diss. California, Davis. Use of three inoculation methods in screening cowpea geno- Ehlers, J. Correlation of performance of sole-crop and types for resistance to two Colletotrichum species. Plant Dis. Field Crops Res. Ahmed, F.
Heat injury Ehlers, J. Introgression of agronomic during floral bud development in cowpea Vigna unguiculata, characters from exotic cowpea germplasm into blackeye bean. Ashraf, M. Farming systems approach: Research on cow- Ehlers, J. Genotypic classification of peas and extension. Rachie, cowpea based on responses to heat and photoperiod.
Wiley, New York, pp. Ehlers, V. Heat tolerance of contrasting Barone, A. Embryological study of crosses cowpea lines in short and long days. Ng, press. Heat tolerance during flower- Cowpea Research, Production and Utilization. Wiley, New ing and heat and chilling tolerance dtLdng germination are not York, pp. Hall, A. Cowpea breeding. Elowad, H. Influences of early and late Plant Breeding Reviews Vol. In: Emechebe, A.
Shoot and pod diseases Hampton, R. Viral of cowpea induced by fungi and bacteria. Singh diseases of cowpea and their control by resistance-conferring and M. Raj, Advances in Cowpea Erwin, D. Blackeye bean root rot diseases indentified. Helms, D. Gepts, P. Registration of 'California Blackeye 46' Fads, D. The chromosomes of Vigna sinensis L. Improved cowpea cultivars for the horticultural K. Registration of 'California industry in the USA.
Rachie, Blackeye 88' cowpea. Cowpea Research, Production and Utilization. Wiley, New Ismail, A. Chilling tolerance York, pp. The cowpea: production, utilization, and re- slow electrolyte leakage. Ismail, A. Positive and negative effects Fery, R. An assessment of two. Jackai, L. A field screening technique for resistance of Fery, R. Genetic analysis of the green Studies on the feeding behavior of Clavi- J. Hemiptera: Coridae and their Fery, R.
Cowpea genetics: a review of potential use in bioassays for host plant resistance. Zeitschrift the recent literature. Raj, Advances fur angewandte Entomologie, Screening techniques for Fery, R. Grain southernpea. Legume Bul. IITA , Galasso, I. Location and organization of major repetitive DNA L.
Bressan, R. Developing a trans- B. Raj, Gwathmey, C. Adaptation to midseason Advances in Cowpea Research. Cowpea virus diseases in the United States: a traits. Miller, Jr. Miller and R. Gwathmey, C. Adaptive Fery, Cowpea Research: a U. Texas Agr. Kwapata, M. Effects of moisture regime Hall, A.
Breeding for heat tolerance. Plant Breed. Field Hall, A. Physiology and breeding for heat tolerance in Crops Res. In: ed. Kuo, Kwapata, M. Pod production. Frate, eds. Blackeye Bean Production Lane, J. Singh, in California. Virulence characteristics of a new Natural Resources, Pub. Breeding for resistance to southern Benin on cowpea. Euphytica, Rachie, Lin, M. Wiley, New York, pp. Ntare, B. Marfo, K. Inheritance of heat tolerance Evaluation of early generation selection procedures for yield during pod set in cowpea.
Genetic, performance and behavioral varia- 9:
0コメント