This study explores the use of genetic variability for advancing the genetic improvement of Cowpea (Vigna unguiculata (L.) Walp), particularly in response to insect infestation stress. Over a period spanning 2015 to 2...This study explores the use of genetic variability for advancing the genetic improvement of Cowpea (Vigna unguiculata (L.) Walp), particularly in response to insect infestation stress. Over a period spanning 2015 to 2017, forty accessions of cowpeas were evaluated to determine their variability under both insecticide spray and no insecticide spray conditions at the Teachings and Research Farms, Federal University of Agriculture, Abeokuta. The experimental design was a randomized complete block design in three replicates. The accessions were evaluated for plant height, leaf length, leaf width, number of days of 50% flowering, number of pods per plant, pod length, number of seeds per plant, 100-seed weight, and seed yield. Data collected were subjected to principal component and single linkage cluster analyses. Principal axis I (PCA1) accounted for 39% and 35% under insecticide spray and no insecticide spray respectively to the total variation in the accessions. Plant height with a factor score of 0.38, leaf length (0.41), number of leaves (0.37), and 100-seed, weight (0.30) was related to PCAI under insecticide spray while leaf width (0.32). Pod length (0.37) and number of seeds/plant (0.38) were significant to PCA1 under no insecticide spray. Notably, accessions such as SAMPEA6, SAMPEA10, IFE-Brown, and IFE-BPE exhibited consistent performance across both conditions, while others displayed condition-specific attributes. For instance, NGB1063, NGB1152, and NGB1093 demonstrated distinct traits under insecticide spray, while NGB1146 and NGB1124 exhibited notable characteristics under no insecticide spray conditions. Therefore, identifying these forty accessions with desirable traits hold promise for future genetic improvement efforts of cowpea cultivation in Nigeria and beyond.展开更多
Cowpea(Vigna imguicuiata) is an important legume crop with diverse uses. The species is presently a minor crop, and evaluation of its genetic diversity has been very limited. In this study, a total of 200 genic and 10...Cowpea(Vigna imguicuiata) is an important legume crop with diverse uses. The species is presently a minor crop, and evaluation of its genetic diversity has been very limited. In this study, a total of 200 genic and 100 genomic simple sequence repeat(SSR) markers were developed from cowpea unigene and genome sequences, respectively. Among them, 27 genic and 27 genomic SSR markers were polymorphic and were used for assessment of genetic diversity and population structure in 105 selected cowpea accessions. A total of 155 alleles and 2.9 alleles per marker were identified, and the average polymorphic information content(PIC) value was 0.3615. The average PIC of genomic SSRs(0.3996) was higher than that of genic SSRs(0.3235), and most of the polymorphic genomic SSRs were composed of di-and trinucleotide repeats(51.9% and 37.0% of all loci, respectively). The low level of detected genetic diversity may be attributed to a severe genetic bottleneck that occurred during the cowpea domestication process. The accessions were classified by structure and cluster analysis into four subgroups that correlated well with their geographic origins or collection sites. The classification results were also consistent with the results from principal coordinate analysis and can be used as a guide during future germplasm collection and selection of accessions as breeding materials for cultivar improvement. The newly developed genic and genomic SSR markers described in this study will be valuable genomic resources for the assessment of genetic diversity, population structure, evaluation of germplasm accessions, construction of genetic maps, identification of genes of interest,and application of marker-assisted selection in cowpea breeding programs.展开更多
Cowpea (Vigna unguiculata (L.) Walp), a legume crop that is grown in the worldwide, provides beneficial proteins for human consumption and animal feeding. In comparison, Rapid N analyzer as traditional method, has bee...Cowpea (Vigna unguiculata (L.) Walp), a legume crop that is grown in the worldwide, provides beneficial proteins for human consumption and animal feeding. In comparison, Rapid N analyzer as traditional method, has been widely used to measure protein content through the percentage of total nitrogen in the seed’s grounded powder. Near-Infrared Reflectance (NIR) has commonly been used to measure protein content in soybean seeds using whole grain without the need of seed grinding, which makes it possible to obtain fast results at a lower cost-per-analysis than the traditional combustion method. The specific objective of this study is to test a rapid method for measuring cowpea seed protein content by the NIR analyzer comparing to the traditional rapid N analyzer. A total of 240 cowpea genotypes were used in this study, including six seed coat colors, black, blackeye, browneye, cream, pinkeye, and red with 40 cowpea genotypes. The results showed that a linear relationship exists between the NIR analyzer and the Rapid N analyzer in the six different color groups. The correlation efficiency (r) between the seed protein contents from NIR and Rapid N was higher for pinkeye seed (r = 0.867), blackeye (0.771), cream (0.729), browneye (0.700), and red (0.623), respectively, but lower for black seeds, indicating that the NIR analyzer can be used to measure protein content for cowpea seeds with the five types of seed coat except black. Overview, the cowpea seed protein content measured from the NIR analyzer showed a little higher seed protein content. A series of regression models with different seed coat color have been built to adjust to protein content of colorful cowpea seeds from the NIR analyzer. But, it is not recommended to use for black color seeds due to a very low correlation efficiency (r) value with 0.184.展开更多
Cowpea is cultivated on more than 11 million hectares with a worldwide production of 5.4 million tons of dried seeds. Cowpea is an affordable source of protein, which is used as an alternative to soybean for people wh...Cowpea is cultivated on more than 11 million hectares with a worldwide production of 5.4 million tons of dried seeds. Cowpea is an affordable source of protein, which is used as an alternative to soybean for people who are allergic to soybean protein. The aim of this research was to assess the variability of the total seed protein content in cowpea. Eleven Arkansas breeding lines were used in this study. Field experiment design was a randomized complete block design (RCBD) with 2 blocks, and conducted in three different locations within Arkansas State (Fayetteville, Alma, and Hope) in 2015. A standard chemical protocol was performed involving an analysis of the total nitrogen by combustion using an Elementar Rapid N III instrument to estimate the protein content. The average protein content was 25.4%, and ranged from 23.7% to 27.4% with a standard deviation of 1.9%. The significant effects of genotype, environment (location), and genotype by environment were observed for the total seed protein content in cowpea. The broad sense heritability (H<sup>2</sup>) for cowpea seed protein was estimated to be 57.8% based on the eleven cowpea genotypes studied. The cowpea lines, “Early Scarlet” and 09-204 had the highest seed protein content with 27.4% and 26.9% dried seed weight, respectively. This study provides valuable information on cowpea protein content for breeders to select and utilize those breeding lines with high seed protein content to develop new high protein cowpea cultivars.展开更多
Previous genetic studies in cowpea [Vigna unguiculata (L.) Walp] have shown that an active bipartite transposable element (TE) is responsible for a range of mutant phenotypes of its leaf, stem and flower. Since type I...Previous genetic studies in cowpea [Vigna unguiculata (L.) Walp] have shown that an active bipartite transposable element (TE) is responsible for a range of mutant phenotypes of its leaf, stem and flower. Since type II TEs have not been characterized at the molecular level in cowpea, this study was initiated to survey the presence of type II TEs in the cowpea genome. Type II TEs: Enhancer/Suppressor-mutator (En/Spm) and Miniature Inverted-repeat Transposable Elements (MITEs) were isolated and characterized. The sequence identity between the EnSpm TE clones was 46% at the nucleotide level (NL) and 30% at the amino acid level (AL) while that of MITEs was 71% at NL and 63% at AL. These cowpea En/Spm TEs were 80% homologous with En/Spm elements of other crops at NL and 46% at AL. The MITEs were 96% similar at NL and 18% homologous at AL. DNA gel blot analysis confirmed the presence of the En/Spm TEs in cowpea. RT-PCR (reverse transcriptase polymerase chain reaction) analysis showed that the VuEnSpm-3 and the MITE clone, VuPIF-1 were actively transcribed in wild type and mutant cowpea tissues. Overall, our data show that multiple, divergent lineages of En/Spm and MITEs are present in the cowpea genome, some of which are actively transcribed. Our findings also offer new molecular resource to further investigate the genetic determinants underlying previously described mutant cowpea phenotypes.展开更多
Savanna regions of Nigeria are deficient in nitrogen and phosphorus, which retard the growth and yield of crops. Therefore, a study was conducted in the wet season of 2006 at the Dry Land Teaching and Research Farm of...Savanna regions of Nigeria are deficient in nitrogen and phosphorus, which retard the growth and yield of crops. Therefore, a study was conducted in the wet season of 2006 at the Dry Land Teaching and Research Farm of Usmanu Danfodiyo University, Sokoto to evaluate the effect of phosphorus on the growth and yield of two cowpea varieties sourced from Republic of Niger. Treatment consisted of four (4) rates of phosphorus (0, 20, 40, 60 kg.ha–1) factorialy combined with (2) varieties of cowpea (kvx303096G and TN5-78) and laid out in a randomized complete block design (RCBD) replicated three (3) times. Results showed significant response to applied P on pods per plant, grain and stover yield and 100-seed weight with highest response to the application of 60 kg.P.ha–1. From this study it can be concluded that KVX303096G and TN5-78 could both be sown under Sokoto condition to obtain reasonable yield of about 1 t.ha–1 of grain and 1.6 t.ha–1 of stover. Irrespective of the varieties, application of 60 kg P2O5 ha–1 could be recommended for higher yield of cowpea (1.4 t.ha–1) relative to 0 kg.P.ha–1 that yielded 1.0 t.ha–1.展开更多
Cowpea [Vigna unguiculata (L.)] is one of the most important arid legumes cultivated for pulse and forage production. Drought is one of the most damageable constraints to crop production impacting negatively food secu...Cowpea [Vigna unguiculata (L.)] is one of the most important arid legumes cultivated for pulse and forage production. Drought is one of the most damageable constraints to crop production impacting negatively food security. The potential of cowpea to address food security is well established. However, not much is known about the base index selection method in breeding cowpea for drought tolerance, which is important for yields. Consequently, the present study has been conducted to: 1) evaluate the yield performance of cowpea genotypes under artificial drought and well-watered condition, 2) ranke genotype performance using selection indices, and 3) assess relationship between agronomic traits and yield. The experiment was the 2 watering conditions laid out in a Randomized Complete Block Design (RCBD) with three replications. The experiment was carried out in pots under screen house at the Department of Horticulture at KNUST. The result showed that KPR1-96-73, Simbo, CZ06-4-16, Wilibaly and Agyenkwa were high yielding in well-water condition while Ghana Shoba, Sangaraka, Nketewade, Ghana Shoni and Korobalen were high yielding genotypes in water stress condition. The average yield reduction was 60.6% and 16% for grain and fodder yield respectively. The biplot displays revealed four groups among the genotypes tested which were based on their yielding capacity and drought tolerance. In cluster B high yielding and drought tolerant genotypes were identified, high yielding and drought susceptible have been identified in cluster A, low yielding and drought tolerant in cluster D, and lastly low yielding and drought susceptible in cluster C. Genotypes in cluster B were best due to the fact that it combines high yield and tolerance to drought. They were Ghana Shoni, Nketewade, Sangaraka and Ghana Shoba. These genotypes might be suitably employed in further drought tolerance breeding programs of cowpea. Significant relationships were observed between agronomic trait and yields under drought condition.展开更多
Cowpea [(Vigna unguiculata (L.)] is one of the most important arid legumes cultivated for pulse and forage production. However, in cowpea, not much is known about the base index selection method in breeding for drough...Cowpea [(Vigna unguiculata (L.)] is one of the most important arid legumes cultivated for pulse and forage production. However, in cowpea, not much is known about the base index selection method in breeding for drought tolerance. Consequently, the present study has been conducted to: 1) evaluate the yield performance of cowpea genotypes under artificial drought and well-watered condition;2) develop a base index using multiple traits for ranking genotype performance. The experiment was a 25 × 2 factorial laid out in a Randomized Complete Block Design (RCBD) with three replications. The experiment was carried out in the screen house at the Department of Horticulture at KNUST. The result showed that KPR1-96-73, Simbo, CZ06-4-16, Wilibaly and Agyenkwa were high yielding in well-water condition while Ghana Shoba, Sangaraka, NKetewade, Ghana-Shoni and Korobalen were high yielding genotypes in water stress condition. The average yield reduction was 60.6% for grain respectively. The biplot displays revealed four groups among the genotypes tested which was based on their yielding capacity and drought tolerance. In cluster B high yielding and drought tolerant genotypes were identified, high yielding and drought susceptible have been identified in cluster A, low yielding and drought tolerant in cluster D, and lastly low yielding and drought susceptible in cluster C. Genotypes in cluster B, were the best due to the fact that it combines high yield and tolerance to drought. They were Ghana Shoni, Nketewade, Sangaraka and Ghana shoba. These genotypes might be suitably employed in further drought tolerance breeding program of cowpea.展开更多
The objective of this study was to characterize environment factors involved in loss of seed viability during storage in open granaries. The temperature and relative humidity of the granary as well as the equilibrium ...The objective of this study was to characterize environment factors involved in loss of seed viability during storage in open granaries. The temperature and relative humidity of the granary as well as the equilibrium moisture content of seeds were determined monthly. Their effects on the loss of viability of maize (<i>Zea mays</i> L.) and cowpea (<i>Vigna unguiculata</i> (L.) Walp.) seeds were examined. The results showed that relative humidity levels > 65% associated with temperatures > 25°C (conditions in the open granary) do not guarantee safe storage of maize lots for a period of 9 to 12 months. Based on these data and the results of seed viability analysis, local environmental conditions in Gandajika (DR-Congo) and seed genetic background are the main factors for the rapid deterioration of seeds during storage. The germination rate correlated negatively with storage duration (<span style="font-family:;" "="">-0.94) and temperature (-0.57) while it correlates positively with the relative humidity (0.58) for both lots of maize analyzed. The same trend was observed with the two-cowpea varieties studied (IT82D-889 and Diamant). Similar work using more varieties in other granaries is required to validate key factors involved in seed viability during storage in targeted regions.</span>展开更多
Vigna unguiculata L. Walp is a recalcitrant plant in terms of in vitro cell, tissue and organ differentiation, which makes it difficult to apply tissue-culture dependant approaches for obtaining stable genetic transfo...Vigna unguiculata L. Walp is a recalcitrant plant in terms of in vitro cell, tissue and organ differentiation, which makes it difficult to apply tissue-culture dependant approaches for obtaining stable genetic transformation in cowpea. Despite this, sporadic efforts have been made to develop regeneration systems in cowpea during the past 40 years. This review presents the considerable progress on cowpea regeneration （organogenesis and embryogenesis） and especially focuses on the regeneration mode of organogenesis, including highlights of the effect of genotypes, explants, medium and plant hormones used in tissue culture. The existing problems and the future research directions were also discussed.展开更多
文摘This study explores the use of genetic variability for advancing the genetic improvement of Cowpea (Vigna unguiculata (L.) Walp), particularly in response to insect infestation stress. Over a period spanning 2015 to 2017, forty accessions of cowpeas were evaluated to determine their variability under both insecticide spray and no insecticide spray conditions at the Teachings and Research Farms, Federal University of Agriculture, Abeokuta. The experimental design was a randomized complete block design in three replicates. The accessions were evaluated for plant height, leaf length, leaf width, number of days of 50% flowering, number of pods per plant, pod length, number of seeds per plant, 100-seed weight, and seed yield. Data collected were subjected to principal component and single linkage cluster analyses. Principal axis I (PCA1) accounted for 39% and 35% under insecticide spray and no insecticide spray respectively to the total variation in the accessions. Plant height with a factor score of 0.38, leaf length (0.41), number of leaves (0.37), and 100-seed, weight (0.30) was related to PCAI under insecticide spray while leaf width (0.32). Pod length (0.37) and number of seeds/plant (0.38) were significant to PCA1 under no insecticide spray. Notably, accessions such as SAMPEA6, SAMPEA10, IFE-Brown, and IFE-BPE exhibited consistent performance across both conditions, while others displayed condition-specific attributes. For instance, NGB1063, NGB1152, and NGB1093 demonstrated distinct traits under insecticide spray, while NGB1146 and NGB1124 exhibited notable characteristics under no insecticide spray conditions. Therefore, identifying these forty accessions with desirable traits hold promise for future genetic improvement efforts of cowpea cultivation in Nigeria and beyond.
基金funded by the Agricultural Science and Technology Innovation Program (ASTIP) of CAASthe China Agriculture Research System (CARS-09)
文摘Cowpea(Vigna imguicuiata) is an important legume crop with diverse uses. The species is presently a minor crop, and evaluation of its genetic diversity has been very limited. In this study, a total of 200 genic and 100 genomic simple sequence repeat(SSR) markers were developed from cowpea unigene and genome sequences, respectively. Among them, 27 genic and 27 genomic SSR markers were polymorphic and were used for assessment of genetic diversity and population structure in 105 selected cowpea accessions. A total of 155 alleles and 2.9 alleles per marker were identified, and the average polymorphic information content(PIC) value was 0.3615. The average PIC of genomic SSRs(0.3996) was higher than that of genic SSRs(0.3235), and most of the polymorphic genomic SSRs were composed of di-and trinucleotide repeats(51.9% and 37.0% of all loci, respectively). The low level of detected genetic diversity may be attributed to a severe genetic bottleneck that occurred during the cowpea domestication process. The accessions were classified by structure and cluster analysis into four subgroups that correlated well with their geographic origins or collection sites. The classification results were also consistent with the results from principal coordinate analysis and can be used as a guide during future germplasm collection and selection of accessions as breeding materials for cultivar improvement. The newly developed genic and genomic SSR markers described in this study will be valuable genomic resources for the assessment of genetic diversity, population structure, evaluation of germplasm accessions, construction of genetic maps, identification of genes of interest,and application of marker-assisted selection in cowpea breeding programs.
文摘Cowpea (Vigna unguiculata (L.) Walp), a legume crop that is grown in the worldwide, provides beneficial proteins for human consumption and animal feeding. In comparison, Rapid N analyzer as traditional method, has been widely used to measure protein content through the percentage of total nitrogen in the seed’s grounded powder. Near-Infrared Reflectance (NIR) has commonly been used to measure protein content in soybean seeds using whole grain without the need of seed grinding, which makes it possible to obtain fast results at a lower cost-per-analysis than the traditional combustion method. The specific objective of this study is to test a rapid method for measuring cowpea seed protein content by the NIR analyzer comparing to the traditional rapid N analyzer. A total of 240 cowpea genotypes were used in this study, including six seed coat colors, black, blackeye, browneye, cream, pinkeye, and red with 40 cowpea genotypes. The results showed that a linear relationship exists between the NIR analyzer and the Rapid N analyzer in the six different color groups. The correlation efficiency (r) between the seed protein contents from NIR and Rapid N was higher for pinkeye seed (r = 0.867), blackeye (0.771), cream (0.729), browneye (0.700), and red (0.623), respectively, but lower for black seeds, indicating that the NIR analyzer can be used to measure protein content for cowpea seeds with the five types of seed coat except black. Overview, the cowpea seed protein content measured from the NIR analyzer showed a little higher seed protein content. A series of regression models with different seed coat color have been built to adjust to protein content of colorful cowpea seeds from the NIR analyzer. But, it is not recommended to use for black color seeds due to a very low correlation efficiency (r) value with 0.184.
文摘Cowpea is cultivated on more than 11 million hectares with a worldwide production of 5.4 million tons of dried seeds. Cowpea is an affordable source of protein, which is used as an alternative to soybean for people who are allergic to soybean protein. The aim of this research was to assess the variability of the total seed protein content in cowpea. Eleven Arkansas breeding lines were used in this study. Field experiment design was a randomized complete block design (RCBD) with 2 blocks, and conducted in three different locations within Arkansas State (Fayetteville, Alma, and Hope) in 2015. A standard chemical protocol was performed involving an analysis of the total nitrogen by combustion using an Elementar Rapid N III instrument to estimate the protein content. The average protein content was 25.4%, and ranged from 23.7% to 27.4% with a standard deviation of 1.9%. The significant effects of genotype, environment (location), and genotype by environment were observed for the total seed protein content in cowpea. The broad sense heritability (H<sup>2</sup>) for cowpea seed protein was estimated to be 57.8% based on the eleven cowpea genotypes studied. The cowpea lines, “Early Scarlet” and 09-204 had the highest seed protein content with 27.4% and 26.9% dried seed weight, respectively. This study provides valuable information on cowpea protein content for breeders to select and utilize those breeding lines with high seed protein content to develop new high protein cowpea cultivars.
文摘Previous genetic studies in cowpea [Vigna unguiculata (L.) Walp] have shown that an active bipartite transposable element (TE) is responsible for a range of mutant phenotypes of its leaf, stem and flower. Since type II TEs have not been characterized at the molecular level in cowpea, this study was initiated to survey the presence of type II TEs in the cowpea genome. Type II TEs: Enhancer/Suppressor-mutator (En/Spm) and Miniature Inverted-repeat Transposable Elements (MITEs) were isolated and characterized. The sequence identity between the EnSpm TE clones was 46% at the nucleotide level (NL) and 30% at the amino acid level (AL) while that of MITEs was 71% at NL and 63% at AL. These cowpea En/Spm TEs were 80% homologous with En/Spm elements of other crops at NL and 46% at AL. The MITEs were 96% similar at NL and 18% homologous at AL. DNA gel blot analysis confirmed the presence of the En/Spm TEs in cowpea. RT-PCR (reverse transcriptase polymerase chain reaction) analysis showed that the VuEnSpm-3 and the MITE clone, VuPIF-1 were actively transcribed in wild type and mutant cowpea tissues. Overall, our data show that multiple, divergent lineages of En/Spm and MITEs are present in the cowpea genome, some of which are actively transcribed. Our findings also offer new molecular resource to further investigate the genetic determinants underlying previously described mutant cowpea phenotypes.
文摘Savanna regions of Nigeria are deficient in nitrogen and phosphorus, which retard the growth and yield of crops. Therefore, a study was conducted in the wet season of 2006 at the Dry Land Teaching and Research Farm of Usmanu Danfodiyo University, Sokoto to evaluate the effect of phosphorus on the growth and yield of two cowpea varieties sourced from Republic of Niger. Treatment consisted of four (4) rates of phosphorus (0, 20, 40, 60 kg.ha–1) factorialy combined with (2) varieties of cowpea (kvx303096G and TN5-78) and laid out in a randomized complete block design (RCBD) replicated three (3) times. Results showed significant response to applied P on pods per plant, grain and stover yield and 100-seed weight with highest response to the application of 60 kg.P.ha–1. From this study it can be concluded that KVX303096G and TN5-78 could both be sown under Sokoto condition to obtain reasonable yield of about 1 t.ha–1 of grain and 1.6 t.ha–1 of stover. Irrespective of the varieties, application of 60 kg P2O5 ha–1 could be recommended for higher yield of cowpea (1.4 t.ha–1) relative to 0 kg.P.ha–1 that yielded 1.0 t.ha–1.
文摘Cowpea [Vigna unguiculata (L.)] is one of the most important arid legumes cultivated for pulse and forage production. Drought is one of the most damageable constraints to crop production impacting negatively food security. The potential of cowpea to address food security is well established. However, not much is known about the base index selection method in breeding cowpea for drought tolerance, which is important for yields. Consequently, the present study has been conducted to: 1) evaluate the yield performance of cowpea genotypes under artificial drought and well-watered condition, 2) ranke genotype performance using selection indices, and 3) assess relationship between agronomic traits and yield. The experiment was the 2 watering conditions laid out in a Randomized Complete Block Design (RCBD) with three replications. The experiment was carried out in pots under screen house at the Department of Horticulture at KNUST. The result showed that KPR1-96-73, Simbo, CZ06-4-16, Wilibaly and Agyenkwa were high yielding in well-water condition while Ghana Shoba, Sangaraka, Nketewade, Ghana Shoni and Korobalen were high yielding genotypes in water stress condition. The average yield reduction was 60.6% and 16% for grain and fodder yield respectively. The biplot displays revealed four groups among the genotypes tested which were based on their yielding capacity and drought tolerance. In cluster B high yielding and drought tolerant genotypes were identified, high yielding and drought susceptible have been identified in cluster A, low yielding and drought tolerant in cluster D, and lastly low yielding and drought susceptible in cluster C. Genotypes in cluster B were best due to the fact that it combines high yield and tolerance to drought. They were Ghana Shoni, Nketewade, Sangaraka and Ghana Shoba. These genotypes might be suitably employed in further drought tolerance breeding programs of cowpea. Significant relationships were observed between agronomic trait and yields under drought condition.
文摘Cowpea [(Vigna unguiculata (L.)] is one of the most important arid legumes cultivated for pulse and forage production. However, in cowpea, not much is known about the base index selection method in breeding for drought tolerance. Consequently, the present study has been conducted to: 1) evaluate the yield performance of cowpea genotypes under artificial drought and well-watered condition;2) develop a base index using multiple traits for ranking genotype performance. The experiment was a 25 × 2 factorial laid out in a Randomized Complete Block Design (RCBD) with three replications. The experiment was carried out in the screen house at the Department of Horticulture at KNUST. The result showed that KPR1-96-73, Simbo, CZ06-4-16, Wilibaly and Agyenkwa were high yielding in well-water condition while Ghana Shoba, Sangaraka, NKetewade, Ghana-Shoni and Korobalen were high yielding genotypes in water stress condition. The average yield reduction was 60.6% for grain respectively. The biplot displays revealed four groups among the genotypes tested which was based on their yielding capacity and drought tolerance. In cluster B high yielding and drought tolerant genotypes were identified, high yielding and drought susceptible have been identified in cluster A, low yielding and drought tolerant in cluster D, and lastly low yielding and drought susceptible in cluster C. Genotypes in cluster B, were the best due to the fact that it combines high yield and tolerance to drought. They were Ghana Shoni, Nketewade, Sangaraka and Ghana shoba. These genotypes might be suitably employed in further drought tolerance breeding program of cowpea.
文摘The objective of this study was to characterize environment factors involved in loss of seed viability during storage in open granaries. The temperature and relative humidity of the granary as well as the equilibrium moisture content of seeds were determined monthly. Their effects on the loss of viability of maize (<i>Zea mays</i> L.) and cowpea (<i>Vigna unguiculata</i> (L.) Walp.) seeds were examined. The results showed that relative humidity levels > 65% associated with temperatures > 25°C (conditions in the open granary) do not guarantee safe storage of maize lots for a period of 9 to 12 months. Based on these data and the results of seed viability analysis, local environmental conditions in Gandajika (DR-Congo) and seed genetic background are the main factors for the rapid deterioration of seeds during storage. The germination rate correlated negatively with storage duration (<span style="font-family:;" "="">-0.94) and temperature (-0.57) while it correlates positively with the relative humidity (0.58) for both lots of maize analyzed. The same trend was observed with the two-cowpea varieties studied (IT82D-889 and Diamant). Similar work using more varieties in other granaries is required to validate key factors involved in seed viability during storage in targeted regions.</span>
文摘Vigna unguiculata L. Walp is a recalcitrant plant in terms of in vitro cell, tissue and organ differentiation, which makes it difficult to apply tissue-culture dependant approaches for obtaining stable genetic transformation in cowpea. Despite this, sporadic efforts have been made to develop regeneration systems in cowpea during the past 40 years. This review presents the considerable progress on cowpea regeneration （organogenesis and embryogenesis） and especially focuses on the regeneration mode of organogenesis, including highlights of the effect of genotypes, explants, medium and plant hormones used in tissue culture. The existing problems and the future research directions were also discussed.
