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Chemical desiccation is widely used in agriculture to anticipate harvest and mitigate the effects of adverse environmental conditions. It is applied to both grains and seeds. Although this practice is widely used, there are still significant gaps in understanding the effects of different herbicide application times on seed quality and plant physiological responses. The objective of this study was to evaluate the effects of different herbicide application times on cowpea, focusing on seed quality, physiological responses, and biochemical composition, including chlorophylls, carotenoids, sugars, and proline, under nocturnal desiccation. In the first experiment, eight herbicides and two mixtures were applied at night: diquat, flumioxazin, diquat + flumioxazin, glufosinate ammonium, saflufenacil, carfentrazone, diquat + carfentrazone, atrazine, and glyphosate. All of the tested herbicides caused a reduction in normal seedling formation, with the diquat + carfentrazone combination resulting in 100% abnormal seedlings. A significant decrease in chlorophyll levels (chlorophyll a: 63.5%, chlorophyll b: 50.2%) was observed using diquat, which indicates damage to photosynthetic processes, while the carotenoid content increased. Total soluble sugars and proline were also negatively impacted, reflecting physiological stress and metabolic changes in seedlings. In the second experiment, three application times were tested with diquat, diquat + flumioxazin, and diquat + carfentrazone. Nocturnal application showed the most significant reduction in chlorophyll levels and increased carotenoid levels. Application at noon and late afternoon also significantly changed the soluble sugar and proline levels. These results indicate that the herbicide application time directly influences the seeds’ physiological quality.

Chemical desiccation is widely used in agriculture to anticipate harvest and mitigate the effects of adverse environmental conditions. It is applied to both grains and seeds. Although this practice is widely used, there are still significant gaps in understanding the effects of different herbicide application times on seed quality and plant physiological responses. The objective of this study was to evaluate the effects of different herbicide application times on cowpea, focusing on seed quality, physiological responses, and biochemical composition, including chlorophylls, carotenoids, sugars, and proline, under nocturnal desiccation. In the first experiment, eight herbicides and two mixtures were applied at night: diquat, flumioxazin, diquat + flumioxazin, glufosinate ammonium, saflufenacil, carfentrazone, diquat + carfentrazone, atrazine, and glyphosate. All of the tested herbicides caused a reduction in normal seedling formation, with the diquat + carfentrazone combination resulting in 100% abnormal seedlings. A significant decrease in chlorophyll levels (chlorophyll a: 63.5%, chlorophyll b: 50.2%) was observed using diquat, which indicates damage to photosynthetic processes, while the carotenoid content increased. Total soluble sugars and proline were also negatively impacted, reflecting physiological stress and metabolic changes in seedlings. In the second experiment, three application times were tested with diquat, diquat + flumioxazin, and diquat + carfentrazone. Nocturnal application showed the most significant reduction in chlorophyll levels and increased carotenoid levels. Application at noon and late afternoon also significantly changed the soluble sugar and proline levels. These results indicate that the herbicide application time directly influences the seeds' physiological quality. [ABSTRACT FROM AUTHOR]

Recently, there has been growing interest in the use of summer cover crops that can be grown during summer fallow periods of crop rotation. This study evaluates the potential of sunn hemp (Crotalaria juncea L.), velvetbean [Mucuna pruriens (L.) DC.] and cowpea [Vigna unguiculata (L.) Walp.]. as three annual legumes summer cover crops. The main objective of this review was to conduct global research comparing these summer cover crops to investigate the benefits, challenges, and trade-offs among ecosystems services when implementing these summer cover crops. In European agriculture, there are three main windows in crop rotation when these summer legumes can be grown: Around mid-spring after winter fallow, early summer after harvest of a winter crop, and mid- to late summer after harvest of an early-season crop. All three legumes can suppress weeds while they are actively growing. After termination, their mulch can create unfavorable conditions for weed emergence. Sunn hemp and velvetbean cover crops can cause a reduction in weed biomass of more than 50%. In addition to their ability to suppress weeds, sunn hemp, velvetbean, and cowpea provide a variety of ecosystem services, such as improving soil health, quality, and fertility, controlling pests, and sequestering carbon. The review highlights their promising role in weed suppression and their contribution to sustainable agricultural practices. However, further research is needed to evaluate their performance in weed management and their environmental impact in field trials under different soil-climatic conditions, as cover cropping is an effective practice but highly context-specific. [ABSTRACT FROM AUTHOR]

Copyright of Revista Colombiana de Ciencias Hortícolas is the property of Revista Colombiana de Ciencias Horticolas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Plant endogenous mechanisms are not always sufficient enough to mitigate drought stress, therefore, the exogenous application of elicitors, such as salicylic acid, is necessary. In this study, we assessed the mitigating action of salicylic acid (SA) in cowpea genotypes under drought conditions. An experiment was conducted with two cowpea genotypes and six treatments of drought stress and salicylic acid (T1 = Control, T2 = drought stress (stress), T3 = stress + 0.1 mM of SA, T4 = stress + 0.5 mM of SA, T5 = stress + 1.0 mM of SA, and T6 = stress + 2.0 mM of SA). Plants were evaluated in areas of leaf area, stomatal conductance, photosynthesis, proline content, the activity of antioxidant enzymes, and dry grain production. Drought stress reduces the leaf area, stomatal conductance, photosynthesis, and, consequently, the production of both cowpea genotypes. The growth and production of the BRS Paraguaçu genotype outcompetes the Pingo de Ouro-1-2 genotype, regardless of the stress conditions. The exogenous application of 0.5 mM salicylic acid to cowpea leaves increases SOD activity, decreases CAT activity, and improves the production of both genotypes. The application of 0.5 mM of salicylic acid mitigates drought stress in the cowpea genotype, and the BRS Paraguaçu genotype is more tolerant to drought stress. [ABSTRACT FROM AUTHOR]

IntroductionSalicylic acid has shown promise in alleviating water stress in cultivated plants. However, there is a lack of studies confirming its effectiveness in cowpea plants grown in field conditions. Therefore, this research aimed to evaluate the use of salicylic acid as a water stress mitigator in cowpea cultivars under different irrigation depths in field conditions.MethodsFour cowpea cultivars (BRS Novaera, BRS Tapaihum, BRS Pujante, and BRS Pajeú) were subjected to different treatments: control (W100: 100% replacement of crop evapotranspiration – ETc), W50 (50% of ETc), W50+SA2 (50% of ETc + 276 mg L-1 of SA), and W50+SA4 (50% of ETc + 552 mg L-1 of SA). The treatments were combined in a 4×4 factorial scheme with three replications, arranged in a randomized block design.ResultsWater restriction had a negative impact on the water status, growth, gas exchange, and production of the cultivars while also leading to changes in the antioxidant metabolism and osmolyte concentration. The application of SA enhanced antioxidant activity and the synthesis of osmotic adjusters under stress conditions. The most effective concentration was 276 mg L-1 in stage R2 and 552 mg L-1 in stage V7, respectively. The BRS Pujante cultivar showed increased productivity under water restriction with SA application, while the BRS Tapaihum was the most tolerant among the cultivars studied.DiscussionIn summary, our findings underscore the importance of using SA to mitigate the effects of water restriction on cowpea cultivation. These discoveries are crucial for the sustainability of cowpea production in regions susceptible to drought, which can contribute to food security. We further add that the adoption of new agricultural practices can enhance the resilience and productivity of cowpea as an essential and sustainable food source for vulnerable populations in various parts of the world.

Recently, there has been growing interest in the use of summer cover crops that can be grown during summer fallow periods of crop rotation. This study evaluates the potential of sunn hemp (Crotalaria juncea L.), velvetbean [Mucuna pruriens (L.) DC.] and cowpea [Vigna unguiculata (L.) Walp.]. as three annual legumes summer cover crops. The main objective of this review was to conduct global research comparing these summer cover crops to investigate the benefits, challenges, and trade-offs among ecosystems services when implementing these summer cover crops. In European agriculture, there are three main windows in crop rotation when these summer legumes can be grown: Around mid-spring after winter fallow, early summer after harvest of a winter crop, and mid- to late summer after harvest of an early-season crop. All three legumes can suppress weeds while they are actively growing. After termination, their mulch can create unfavorable conditions for weed emergence. Sunn hemp and velvetbean cover crops can cause a reduction in weed biomass of more than 50%. In addition to their ability to suppress weeds, sunn hemp, velvetbean, and cowpea provide a variety of ecosystem services, such as improving soil health, quality, and fertility, controlling pests, and sequestering carbon. The review highlights their promising role in weed suppression and their contribution to sustainable agricultural practices. However, further research is needed to evaluate their performance in weed management and their environmental impact in field trials under different soil-climatic conditions, as cover cropping is an effective practice but highly context-specific.

Plant endogenous mechanisms are not always sufficient enough to mitigate drought stress, therefore, the exogenous application of elicitors, such as salicylic acid, is necessary. In this study, we assessed the mitigating action of salicylic acid (SA) in cowpea genotypes under drought conditions. An experiment was conducted with two cowpea genotypes and six treatments of drought stress and salicylic acid (T1 = Control, T2 = drought stress (stress), T3 = stress + 0.1 mM of SA, T4 = stress + 0.5 mM of SA, T5 = stress + 1.0 mM of SA, and T6 = stress + 2.0 mM of SA). Plants were evaluated in areas of leaf area, stomatal conductance, photosynthesis, proline content, the activity of antioxidant enzymes, and dry grain production. Drought stress reduces the leaf area, stomatal conductance, photosynthesis, and, consequently, the production of both cowpea genotypes. The growth and production of the BRS Paraguaçu genotype outcompetes the Pingo de Ouro-1-2 genotype, regardless of the stress conditions. The exogenous application of 0.5 mM salicylic acid to cowpea leaves increases SOD activity, decreases CAT activity, and improves the production of both genotypes. The application of 0.5 mM of salicylic acid mitigates drought stress in the cowpea genotype, and the BRS Paraguaçu genotype is more tolerant to drought stress.

In the semi-arid region of Paraíba, cowpea has low productivity due to irregular rainfall and poor use of production technologies. An extensive study aimed at selecting more productive cultivars was conducted using biometric models. This first work had the following objectives: i. Quantify direct and indirect effects of primary and secondary components on grain production; ii. Identify variables with greater potential for cultivar selection in the semiarid region of Paraíba and iii. Determine the most appropriate selection strategies for the evaluated variables. The experiment was conducted in an experimental field. The influence of 6 primary and 6 secondary production components was evaluated on grain yield. Data were subjected to ANOVA. Genetic parameters, correlations and path analysis were estimated. Given the strong direct phenotypic and genotypic effects, pod yield results the most promising variable for higher grain yield selection. Direct and simultaneous selections are the most suitable strategies for the set of evaluated variables. However, further studies on selection indices are necessary to maximize genetic gains. Highlights • Variables with greater potential were identified for the selection of superior cultivars of cowpea in the semiarid region of Paraíba. • The pod yield variable (PP) seems promising for cultivar selection considering higher grain yield (GY).

Low cowpea productivity (Vigna unguiculata (L.) Walp) in the semi-arid region of Paraíba is due, among other factors, to poor-quality cultivars. This research tested biometric models intending to increase productivity of superior cultivars with the following objectives: i. Estimate genetic gains in production components; ii. Identify the selection index model providing the greatest gains through simultaneously selecting a set of variables, and iii. Select cultivars with higher productivity. The experiment was carried out in the experimental field of the Agrifood Science and Technology Center of the Federal University of Campina Grande. Eight cultivars and 13 variables were evaluated. Data were subjected to ANOVA and means were grouped using the Scott and Knott test. Genetic gains were estimated by correlated response, classic selection index, rank sum and index based on desired gains. Direct selection of the secondary pod yield component provides significant genetic gains in main grain yield. Among the methodologies used, the classic selection index provided greater distribution of genetic gains for main grain yield and primary production components. These results allow concluding that Costela de vaca, BRS Marataoã and Paulistinha cultivars should be selected for cultivation and commercial exploitation in the semiarid region of Paraíba. Highlights: • Direct selection of the secondary pod yield component provides significant genetic gains in main grain yield. • The classic selection index provided greater distribution of genetic gains for main grain yield and primary production components. • Cultivars were selected for cultivation and commercial exploitation in the semi-arid region of Paraíba.

Background. Сowpea (Vigna unguiculata (L.) Walp.) is a thermophilic crop; in most countries it is grown for grain and vegetable uses. Positive results of open-field cowpea production in the southern regions of Russia and the possibility of its cultivation on infertile soils in hot and dry climate imply the need to develop new cultivars suitable for wider introduction into Russian agriculture. It is of paramount importance for cowpea breeders to know the patterns of variability in the relationships among agronomic traits and their characteristics in cultivars grown for different uses (grain and vegetable). Besides, acceleration of the breeding process to a large extent depends on the knowledge of the traits that make it possible to differentiate the source material according to its intended purpose.Materials and methods. For three years, 315 cowpea accessions of various origin from the VIR collection were studied in Astrakhan Province, Russia. Eight useful agronomic characters were examined. The variability and relationships of these characters were assessed in cultivars grown for grain and vegetable purposes using multivariate statistical analyses.Results and discussion. The characters that differentiate grain and vegetable cowpea accessions were identified: the type of seed coat surface, the presence of fiber in ventral and dorsal pod sutures and a sclerenchyma layer in pods valves, and pod length. Discriminant functions were calculated for identification and classification of accessions according to their grain and forage uses. The character (presence of depressions or longitudinal striae on the seed coat surface) diagnosing vegetable cowpea cultivars was pinpointed. Characters associated with high seed yield were identified. For grain cultivars such character is the weight of 1000 seeds, while for vegetable cultivars it is a large-seeded and long-fruit pod.

Highlights: Salinity tolerance among traditional varieties of cowpea is variable. High net photosynthesis is observed in cowpea-tolerant varieties under salt stress. The decrease in photosynthesis is caused by stomatal restriction and low photochemical efficiency. Cowpea varieties are similar in photochemical efficiency and photochemical quenching. The decrease in pod number and seeds per pod are the main effects of salinity on cowpea production. Cowpea is the main subsistence crop—protein source—for the Brazilian semi-arid region. The use of salt-stress-tolerant varieties can improve crop yields. We evaluated the effect of irrigation with brackish water on the growth, photosynthetic responses, production, and tolerance of fifteen traditional varieties of cowpea. The experiment was conducted in randomized blocks, in a 15 × 2 factorial scheme, composed of 15 traditional varieties of cowpea and two salinity levels of irrigation water (0.5 and 4.5 dS m−1), with five replicates. Plants were grown in pots containing 10 dm3 of soil for 80 days. The reduction in the photosynthetic rate of cowpea varieties occurs mainly due to the decrease in stomatal conductance caused by salt stress. Salt stress increased the electron transport rate and photochemical quenching of cowpea varieties, but stress-tolerant varieties increased the CO2 assimilation rate and instantaneous carboxylation efficiency. The Ceará, Costela de Vaca, Pingo de Ouro, Ovo de Peru, and Sempre Verde varieties are tolerant to salt stress. Salt stress decreases 26% of the production of tolerant varieties to salt stress and 54% of susceptible varieties. The present findings show the existence of variability for saline stress tolerance in traditional varieties of cowpea and that Ceará, Costela de Vaca, Pingo de Ouro, and Ovo de Peru varieties are more suitable for crops irrigated with saline water. [ABSTRACT FROM AUTHOR]

Recent trends in sustainable agricultural production seek improved bioinoculants that can improve crop adaptation and production and reduce external inputs of pesticides and synthetic fertilisers, particularly under abiotic and biotic stress conditions. Drought is one of the critical and more frequent conditions that can drastically reduce plant bio-mass and yield. In this sense, the use of bioinoculants is a biological strategy to mitigate climate change and reduce the water needs of plants. Leguminous plants are very important in improving sustainable cropping systems because they can form effective symbiotic associations with both nitrogen-fixing bacteria and arbuscular mycorrhizal fungi. These microorganisms can act as an alternative source of nitrogen and can increase phosphorus utilisation from soils and fertilisers. Cowpea is a multipurpose crop that has caused a great interest due to its resistance to abiotic stress. This pot experiment in a greenhouse with non-sterilised soil aimed to test the effect of three previously selected rhizobial bacteria (Rhizobium sp. (B1), Bradyrhizobium elkanii (B2) and Bradyrhizo bium sp. (B3)) and arbuscular mycorrhizal fungi (Claroideoglomus claroideum BEG210) on the yield and crude protein content of cowpea under drought conditions and also to compare the competitiveness of the inoculated bacteria with native rhizobial bacteria naturally present in the soil. The combined inoculation with each bacteria and arbuscular mycorrhizal fungi Claroideoglomus claroideumBEG210 was shown to increase the crude protein content of cowpea seeds in plants under drought stress (25 % of field capacity) by 13 %, 17 %, and 30 %, respectively. This study shows that these microorganisms are potentially resistant to drought and can be used as a biotechnological tool for sustainable agriculture under drought conditions.

O condicionamento fisiológico consiste de uma técnica que visa estimular o metabolismo das sementes frente às situações adversas, sendo aplicada para diversas culturas de expressão econômica, destacando-se o feijão caupi pela sua relevância, principalmente nas regiões Norte e Nordeste do Brasil. Dessa forma, o presente trabalho teve como objetivo avaliar o efeito do condicionamento fisiológico e posterior secagem sobre o potencial germinativo das sementes de feijão caupi, cv. BRS Potengi. O primeiro experimento consistiu em comparar se o uso das mesmas sementes para todos os períodos de embebição (experimento I) ou a utilização de novas sementes a cada período poderiam interferir na construção da curva de embebição (30’; 1; 3; 6; 9; 12; 18 e 24 horas). Previamente foi avaliado o período de embebição necessário para que as sementes atingissem a fase II do processo trifásico de embebição, sem iniciar a fase III. No segundo experimento, utilizando a metodologia II de embebição, as sementes após cada período de embebição foram divididas em duas frações, sendo uma delas mantida úmida (fração úmida) até a semeadura e a outra submetida ao processo de secagem (fração seca). Foi utilizado o delineamento inteiramente casualizado, adotando-se para o segundo experimento um esquema fatorial 2×7 + testemunha (sementes sem embebição), ou seja, presença e ausência de secagem após o condicionamento fisiológico × períodos de embebição. Avaliou-se: teor de água; germinação (protrusão da raiz primária); índice de velocidade, coeficiente de velocidade e tempo médio de protrusão da raiz primária e condutividade elétrica. A curva de embebição pode ser conduzida de forma eficiente utilizando as mesmas sementes durante todos os períodos de avaliação ou fazendo uso de novas sementes a cada período. Visando-se o uso de menos sementes e uma melhor otimização do tempo para a preparação e a condução do experimento de embebição, indica-se a metodologia que utiliza as mesmas sementes para todos os períodos de embebição. O condicionamento fisiológico das sementes por 18 e 24 horas, sem posterior secagem, proporciona uma emissão mais rápida da raiz primária das sementes de feijão caupi, cv. BRS Potengi. O processo de secagem das sementes não interfere no efeito benéfico do condicionamento fisiológico.

ABSTRACT: We evaluated the compatibility between two nitrogen–fixing Bradyrhizobium inoculant strains and phosphate–solubilizing fungal strains and the effect of co–inoculation of these bacterial and fungal strains on cowpea growth under different N and P conditions. First, the compatibility between Bradyrhizobium strains UFLA03–84 and INPA03–11B and fungi Haematonectria ipomoeae FSA381, Eleutherascus lectardii FSA257a, Pochonia chlamydosporia var. catenulata FSA109, and Acremonium polychromum FSA115 was tested in both solid and liquid media. Cowpea growth and nodulation promotion under two mineral N doses and two P conditions (a low dose of soluble P plus a high dose of Ca3(PO4)2 and another condition with a high dose of soluble P) were tested with two N2 fixing Bradyrhizobium strains co–inoculated with each of the P–solubilizing fungal strains FSA109, FSA115, and FSA381. There was compatibility between each fungal strain and the two Bradyrhizobium strains, except for FSA257a with either of the bacterial strains in liquid medium. When both mineral N and P were limiting, plants were able to grow and accumulate N and P based on biological N2 fixation and solubilization of calcium phosphate in the same amount as the mineral N and soluble phosphate. Even when both nutrients were fully available, the type of co–inoculation promoted plant growth and nutrient accumulation. The responses varied in accordance with the co–inoculated strains, the N source, and the P source, reflecting the enormous complexity of the biological interactions between plants and microorganisms, and the nutrient conditions provided by the environment.

The objective of this study was to evaluate and quantify the genetic divergence between accessions of cowpea, aiming to identify the characters that most contribute to diversity and select superior parents. Seventy-six cowpea accessions were evaluated using 19 descriptors that were also utilized to estimate genetic diversity using the Shannon-Weaver index. Phenology and production data were analyzed using descriptive statistics and were subjected to Pearson’s correlation test. The descriptors flower color, pod color, and seed brightness showed greater variability in the quantification of genetic diversity. The genotypes Das Almas, Galanjão, selected from CE-13, 7907-Purple Hull and Caupi Branco should be incorporated into cowpea breeding programs as they exhibit desirable agronomic characters. Crossings involving the genotype 7907-Purple Hull with Das Almas and Galanjão are indicated, which could result in obtaining superior genotypes in terms of precocity and grain yield.

Copyright of Agronomía Colombiana is the property of Universidad Nacional de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

O feijão-caupi (Vigna unguiculata (L.) Walp.) atua como componente essencial dos sistemas de produção das regiões Nordeste e Norte do Brasil, onde a produção se dá através de práticas tradicionais realizadas por pequenos produtores, utilizando para produção de grãos verdes os mesmos materiais que são usados para a produção de grãos secos. Isto ocorre devido a carência de genótipos comerciais voltados para a produção de feijão-verde. O uso de materiais não adequados à produção de grãos verdes acarreta perdas ao produtor, devido muitos genótipos não apresentarem características adequadas. Deste modo, o objetivo desse estudo foi avaliar vinte e dois genótipos de feijão-caupi para a produção de grãos verdes em Mossoró/RN. O experimento foi instalado na Horta Experimental do Departamento de Ciências Agronômicas e Florestais (DCAF) da Universidade Federal Rural Semi-Árido (UFERSA), Mossoró/RN. Utilizou-se delineamento em blocos casualizados completos com 22 tratamentos e quatro repetições. Os tratamentos consistiram em genótipos de feijão-caupi, sendo 19 provenientes da Embrapa Meio-Norte, e três cultivares regionais. As colheitas foram realizadas manualmente, conforme a maturação das vagens para feijão-verde. Após a colheita, as vagens foram conduzidas ao laboratório de Pós Colheita da UFERSA/DCAF. As características avaliadas foram: Precocidade dos genótipos (NDIF), Comprimento médio de vagens verdes (COMPVV), Peso médio de vagens verdes (PSVV), Peso médio de grãos por vagem (PSGV), Produtividade de vagens verdes (PVV), Produtividade de grãos verdes (PGV), Índice de grãos verdes (IGV). Os dados obtidos foram submetidos à análise de variância e as médias dos tratamentos comparadas pelo teste de Scott-Knott a 5% de probabilidade. As análises estatísticas foram realizadas com auxílio do programa Sisvar. Os genótipos BRS Tumucumaque e Paulistinha se destacaram quanto o NDIF, COMPVV, PSVV, PSGV, PVV e IGV, apresentando potencial para exploração comercial nas condições ambientais em que foram avaliados.

Cowpea is the main subsistence crop—protein source—for the Brazilian semi-arid region. The use of salt-stress-tolerant varieties can improve crop yields. We evaluated the effect of irrigation with brackish water on the growth, photosynthetic responses, production, and tolerance of fifteen traditional varieties of cowpea. The experiment was conducted in randomized blocks, in a 15 × 2 factorial scheme, composed of 15 traditional varieties of cowpea and two salinity levels of irrigation water (0.5 and 4.5 dS m−1), with five replicates. Plants were grown in pots containing 10 dm3 of soil for 80 days. The reduction in the photosynthetic rate of cowpea varieties occurs mainly due to the decrease in stomatal conductance caused by salt stress. Salt stress increased the electron transport rate and photochemical quenching of cowpea varieties, but stress-tolerant varieties increased the CO2 assimilation rate and instantaneous carboxylation efficiency. The Ceará, Costela de Vaca, Pingo de Ouro, Ovo de Peru, and Sempre Verde varieties are tolerant to salt stress. Salt stress decreases 26% of the production of tolerant varieties to salt stress and 54% of susceptible varieties. The present findings show the existence of variability for saline stress tolerance in traditional varieties of cowpea and that Ceará, Costela de Vaca, Pingo de Ouro, and Ovo de Peru varieties are more suitable for crops irrigated with saline water.

Introduction: Salicylic acid has shown promise in alleviating water stress in cultivated plants. However, there is a lack of studies confirming its effectiveness in cowpea plants grown in field conditions. Therefore, this research aimed to evaluate the use of salicylic acid as a water stress mitigator in cowpea cultivars under different irrigation depths in field conditions., Methods: Four cowpea cultivars (BRS Novaera, BRS Tapaihum, BRS Pujante, and BRS Pajeú) were subjected to different treatments: control (W100: 100% replacement of crop evapotranspiration - ETc), W50 (50% of ETc), W50+SA2 (50% of ETc + 276 mg L -1 of SA), and W50+SA4 (50% of ETc + 552 mg L -1 of SA). The treatments were combined in a 4×4 factorial scheme with three replications, arranged in a randomized block design., Results: Water restriction had a negative impact on the water status, growth, gas exchange, and production of the cultivars while also leading to changes in the antioxidant metabolism and osmolyte concentration. The application of SA enhanced antioxidant activity and the synthesis of osmotic adjusters under stress conditions. The most effective concentration was 276 mg L -1 in stage R2 and 552 mg L -1 in stage V7, respectively. The BRS Pujante cultivar showed increased productivity under water restriction with SA application, while the BRS Tapaihum was the most tolerant among the cultivars studied., Discussion: In summary, our findings underscore the importance of using SA to mitigate the effects of water restriction on cowpea cultivation. These discoveries are crucial for the sustainability of cowpea production in regions susceptible to drought, which can contribute to food security. We further add that the adoption of new agricultural practices can enhance the resilience and productivity of cowpea as an essential and sustainable food source for vulnerable populations in various parts of the world., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Cavalcante, de Melo, Ferraz, de Alencar, Dias, Viana, Rocha, Ndhlala, Sá, de Lacerda and Viégas.)

The southeastern mesoregion of the Brazilian Pará state is an important soybean producer, and the second-crop system can increase the local agricultural production. However, Latosols with medium to very clayey texture predominate in the region and, despite being suitable for farming, they naturally have low levels of available phosphorus (P). This study aimed to evaluate the yield of second-crop cowpea [Vigna unguiculata (L.) Walp] under doses of residual P in a Yellow-Latosol. Two experiments were installed under field conditions. The experimental design was randomized blocks, with five treatments (residuals of 0, 50, 100, 150 and 200 kg ha-1 of P2O5) and four replications. The first experiment consisted of cultivating second-crop cowpea after the soybean harvest, with phosphate doses provided during the soybean planting, and the second of second-crop cowpea after the rice harvest, with phosphate doses provided during the rice planting. The 1,000-grain weight and production of pods, husks and grains were evaluated. The production of pods and husks were higher in the area with residual P. The highest yield was obtained in the residual dose of 200 kg ha-1 of P2O5, reaching a grain yield of 1,256 kg ha-1 after the soybean harvest and 885 kg ha-1 after the rice harvest.

O feijão-caupi é uma cultura muito importante para a agricultura brasileira, pois vem sendo bastante cultivado na região Nordeste do País, se destacando na ocupação de mão-de-obra e fazendo parte de produtos agrícola exportados pelo Brasil. O objetivo desta pesquisa foi avaliar o crescimento inicial do feijão caupi fertirrigado com urina humana como fonte alternativa de fertilizante. No Campus I da Universidade Federal de Campina Grande, foi instalado um experimento em ambiente protegido com delineamento inteiramente casualizado, composto por cinco tratamentos e quatro repetições. Os tratamentos foram caracterizados por doses de 0, 8, 12, 16,6 e 22 mL de urina aplicada por vaso. Aos 36 DAS (dias após a semeadura) foram determinadas: altura da planta, diâmetro do caule, número de folhas, área foliar, massa seca total, massa seca da parte aérea e número de nódulos nas raízes da planta. Em conformidade com os resultados obtidos, pode-se concluir que a fertirrigação do feijão caupi com urina humana proporcionou incremento na altura das plantas, área foliar, massa seca da parte aérea, massa seca total e que a urina humana apresentou potencialidade para uso na fertirrigação do feijão caupi.

Cowpea has been cultivated in a rudimentary form in the main producing regions of Brazil, resulting in lower grain yields, when compared to the crop potential. The use of technologies such as water regimes, adequate plant density and soil management are alternatives to increase this crop yield. This study aimed at evaluating the effects of different water regimes and plant densities on the yield components of cowpea cultivated under conventional and no-tillage systems. A randomized block design in a split-plot factorial, with four replications, was used. The treatments consisted of five water regimes in the plots (157.00 mm, 189.00 mm, 234.00 mm, 274.00 mm and 320.00 mm) and five plant densities as subplots (12 plants m-2, 16 plants m-2, 20 plants m-2, 24 plants m-2 and 28 plants m-2). The evaluated variables were: number of pods per plant, number of pods per area, pod length and grain yield. The combination between 270 mm of irrigation water depth with a density of 280,000 plants ha-1 resulted in higher grain yield using the no-tillage system, while the combination between the density of 280,000 plants ha-1 and 320 mm of water depth favored the highest grain yields in the conventional growing system.

The population increase and the need of intensifying food production, coupled with the scarcity of water resources, have led to the search of alternatives that reduce consumption and optimize the water use during cultivation. In this context, hydrogels become a strategy in agricultural management, due to their water retention capacity in the soil and availability to plants. This study aimed at evaluating the efficiency of hydrogels on the development and production of cowpea bean ('Sempre-verde' cultivar) under water stress, in a greenhouse. The experiment was performed in a randomized block design, with five replications, in a 4 x 5 factorial scheme, consisting of four types of hydrogel (Hydroplan-EB HyA, with granulometry of 1-3 mm; Hydroplan-EB HyB, with granulometry of 0.5-1 mm; Hydroplan-EB HyC, with granulometry < 0.5 mm; Polim-Agri, with granulometry of 1-0.5 mm) and five concentrations (0 g pot-1; 1.5 g pot-1; 3 g pot-1; 4.5 g pot-1; 6 g pot-1). The following traits were evaluated: number of pods per plant, number of grains per pod and grain yield. The highest concentration (6 g pot-1) resulted in a higher number of pods and yield for all the hydrogels, especially for HyC and Polim-Agro, which presented 7.4 pods plant-1 and 7.0 pods plant-1, with yield of 15.43 g plant-1 and 16.68 g plant-1, respectively. The use of hydrogel shows to be efficient for reducing yield losses under water stress.

Cowpea has great potential for cultivation and rotation in Mato Grosso State and in Brazilian Cerrado due to the large area available in these locations in the off-season. The aim of the current study is to analyze the yield of cowpea (BRS Itaim cultivar) grown in non-irrigated soil in Sorriso County-MT, based on plant population density. The experiment was carried out in commercial area, on March 8, 2015; it followed a randomized block design, with six population densities and four replicates. Population densities comprising 80, 120, 160, 200, 240, and 280 thousand plants per hectare were used in the experiment. Experimental plots encompassed four 5-meter-long rows with 0.45-meter spacing between them. Final plant stand (plants ha-1), number of pods per plant, number of grains per pod, pod length (cm), weight of one hundred grains (g) and grain yield (kg ha-1) in the useful plot were evaluated at harvest time. The number of pods per plant has linearly decreased as population density increased. The number of seeds per pod, pod length and weight of one hundred grains did not change due to population density. Population density of 230 thousand plants ha-1 has enabled the highest grain yield under the tested conditions. [ABSTRACT FROM AUTHOR]

Biological nitrogen fixation has been shown to be indispensable for the sustainability of Brazilian agriculture, due to the supply of nitrogen with low economic cost to crops and reduction in environmental impact. Given the above, the objective of this study was to evaluate the efficiency of rhizobian strains and phosphorus doses, to maximize the growth of two cowpea cultivars and nitrogen fixation and to obtain better agronomic performance. The experimental design was a randomized complete block in a 3 x 6 factorial scheme (2 rhizobium strains + 1 treatment without inoculation x 6 phosphorus doses), containing 4 replications. The doses consisted of 0, 30, 60, 90, 120 and 150 kg ha-1 of P2O5. Potassium fertilization was performed at sowing using 60 kg ha-1 of K2O. Water supply for the crop was performed with irrigation and two-day watering shift, with approximate flow rate of 5 mm. The characteristics evaluated were: chlorophyll performed 45 days after sowing, shoot dry biomass (g), one hundred seed weight (g), total shoot nitrogen (dag kg ha-1) and yield (kg ha-1). In general the two strains tested showed capacity for nodulation and biological nitrogen fixation. The strain INPA 03-11B was the most suitable for cv. BRS Sempre Verde and BR 3299 the most suitable for cv. BRS Vinagre cowpea. The phosphorus dose that conditioned the maximum agronomic efficiency in cowpea ranged from 70 to 110 kg ha-1. Higher nitrogen content for both bean cultivars was verified with the strain BR 3299. [ABSTRACT FROM AUTHOR]

The vigna bean is a very important crop for Brazilian agriculture, since it has been widely cultivated in the Northeast of the country, highlighting the occupation of labor and being part of agricultural products exported by Brazil. The objective of this research was to evaluate the initial growth of fertile bean fertigated with human urine as an alternative source of fertilizer. In Campus I of the Federal University of Campina Grande, an experiment was carried out in a completely randomized design with five treatments and four replications. The treatments were characterized by doses of 0, 8, 12, 16.6 and 22 mL of urine per vessel. The plant height, stem diameter, number of leaves, leaf area, total dry mass, dry shoot mass and number of nodules in the roots of the plant were determined at 36 DAS (days after sowing). In accordance with the results obtained, it can be concluded that the fertigation of vigna beans with human urine provided an increase in plant height, leaf area, aerial part dry mass, total dry mass and that human urine presented potential for use in fertirrigation of the vigna beans. [ABSTRACT FROM AUTHOR]

Objetivou-se avaliar os componentes de produção do feijão-caupi e gergelim, consorciado com a mamoneira no semiárido paraibano. O experimento foi desenvolvido no período de março a novembro de 2011 em condições de campo em Pombal, Paraíba. Realizou-se sob delineamento experimental em blocos ao acaso com três sistemas de cultivo em dois ensaios experimentais: feijão-caupi (cv. BRS Novaera) e gergelim (cv. BRS Seda) em monocultivo, consórcio com mamona cv. IAC 2028 e consórcio com mamona cv. BRS Nordestina, com 4 repetições, totalizando 12 parcelas experimentais em cada ensaio. O consórcio com a mamoneira reduz os componentes de produção e produção do feijão-caupi e gergelim, sendo a cv. BRS Nordestina mais competitiva. Considerando as variáveis estudadas, a melhor opção para cultivo consorciado do feijão-caupi ou gergelim na região é a cv. IAC 2028. Production of cowpea and sesame intercropped with castor bean in semiarid region of Paraiba Abstract: The objective was to evaluate yield components of cowpea and sesame grown as secondary crops, intercropping with castor bean in the semiarid region of Paraiba. The experiment was carried out from March to November 2011 under field conditions in Pombal, Paraíba state. Three experimental systems were used in a randomized block design in two experimental trials: cowpea (cv. BRS Novaera) and sesame (cv. BRS Seda) in monoculture, intercropping with castor bean cv. IAC 2028 and intercropping with castor bean cv. BRS Nordestina, with 4 replicates, totaling 12 experimental plot in each trial. The intercrop with castor bean reduces yield components and yield of cowpea and sesame, with an cv. BRS Nordestina more competitive. Considering the variables studied, the best option for intercropping cowpea or sesame in the region is the cv. IAC 2028.

Los experimentos se realizaron en la Facultad de Ciencias Agrarias de la Universidad Nacional de Asunción, San Lorenzo, Paraguay. El periodo de ejecución estuvo comprendido entre los meses de enero a abril de 2013, este trabajo se realizó con el objetivo de detectar enfermedades virales transmitidas por semillas de poroto (Vigna unguiculata (L.) Walp.), mediante pruebas biológicas y serológicas. Se recolectaron muestras de seis variedades de semillas y plantas de poroto de parcelas infectadas, ubicadas en el Campo experimental del Instituto Paraguayo de Tecnología Agraria (IPTA), Choré, Departamento de San Pedro. Se realizó la siembra de las semillas colectadas, de las variedades San Francisco, Crema Ñu, Chore S·BR1 Poty, Negro, Crema Japonés y Moteado. Las plantas resultantes que presentaron síntomas fueron sometidas al test de ELISA utilizando anticuerpos específicos a los virus Cowpea severe mosaic virus (CpSMV) y Cowpea aphid-borne mosaic virus (CABMV) respectivamente, de manera a detectar la transmisión del virus por semillas. Posteriormente, a partir del material foliar macerado, de las muestras que dieron reacciones positivas en el test, se realizaron inoculaciones mecánicas a plantas sanas de tres especies indicadoras: Chenopodium amaranticolor, Vigna unguiculata y Sesamun indicum. Todas las variedades de poroto dieron positivo al CABMV y al CpSMV solo las variedades negro y moteado. Se detectó la transmisión del CABMV a través de semillas de poroto de la variedad San Francisco, presentando un porcentaje de transmisión del 6%.

The cowpea plays an important role in the Brazilian agricultural production, especially in the North and Northeast Regions, where it is widely cultivated by smallholders. Thus, this study aimed at evaluating the physiological quality of cowpea seeds produced under no-tillage and conventional tillage and different periods without irrigation. A randomized blocks design, in a split-plot scheme, with four replications, was used. The plots consisted of cropping systems (no-tillage and conventional tillage), while the subplots consisted of periods without irrigation (2, 6, 10, 14, 18 and 22 days). In the plots, seeds were collected and subjected to the following evaluations: seeds weight per plant, one thousand seeds weight, test weight, seed length and width, moisture content, germination, accelerated aging, field seedling emergence and emergence speed index. Cowpea seeds from plants subjected to hydric stress resulted in lower physiological quality, but were physically bigger and heavier. The no-tillage system provided seeds with better physiological quality. Cowpea plants subjected to hydric stress after flowering produced fewer seeds.

A medição da condutividade elétrica da solução de embebição de sementes é um procedimento recomendado para avaliar o vigor de sementes de ervilha, sugerido para as de soja. Para as de outras plantas, porém, ainda não está bem fundamentada. Este trabalho teve como objetivo avaliar a qualidade fisiológica de sementes de feijão-caupi. Para isso, o estudo foi conduzido, utilizando-se acessos de feijão-caupi, representados por quatro lotes de sementes. Foram realizados os testes de germinação, primeira contagem de germinação, emergência de plântulas e de condutividade elétrica, usando-se a temperatura de 25 ºC; volumes de água para embebição de 75 e 100 mL, amostras de 25 e 50 sementes; e períodos de embebição de 2, 4, 8, 12 e 24 horas. Utilizou-se o delineamento experimental inteiramente casualizado, com quatro repetições, avaliando-se os efeitos de lotes. Diante dos resultados obtidos, verificou-se que o teste de condutividade elétrica foi eficiente na separação dos lotes de sementes em diferentes níveis de vigor.

The aim of this work was to evaluate the transfer of N via biological nitrogen fixation from green manures to intercropped lettuce using the 15N abundance method. The treatments consisted of lettuce with black oats, lettuce with cowpea, lettuce with white lupin and monocropped lettuce (control). Green manures were sown at two different times including the following: 60 days before transplanting of lettuce seedlings and simultaneous to transplanting of lettuce seedlings. N transfer was estimated using the natural 15N abundance method. It was observed that lettuce intercropped with green manures reached the same fresh mass of monocropped lettuce when the green manures were sown at the same time as the vegetables were planted. However, when the green manures were sown previously, the fresh mass of the monocropped lettuce was higher, and independent of the sowing time of green manures, the monocropped lettuce reached a higher dry mass. White lupin and cowpea transferred higher amounts of N regardless of sowing time, and the C:N ratio of white lupin to cowpea was lower compared to black oats. Intercropping with white lupin, cowpea and black oat transferred 18, 17 and 7% of N, respectively, to lettuce.O objetivo deste trabalho foi estudar a transferência do nitrogênio de adubos verdes para alface em cultivo consorciado, através da técnica da abundância natural de 15N. Os tratamentos foram: alface em monocultivo (testemunha), alface consorciado com aveia-preta, com feijão-caupi e com tremoço-branco, em duas épocas de semeadura dos adubos verdes: 60 dias antes e no transplante das mudas de alface. Observou-se que a alface consorciada com adubos verdes adquiriu a mesma massa fresca das alfaces solteiras quando a semeadura do adubo verde foi simultânea com o plantio da mesma; no entanto quando os adubos verdes foram semeados com 60 dias de antecedência as alfaces solteiras obtiveram maior massa fresca ; independentemente da época de semeadura as alfaces solteiras alcançaram maior massa seca; o tremoço-branco e o caupi transferiram maior quantidade de N para a alface, independentemente de sua época de semeadura; a relação C:N do feijão-caupi e tremoço-branco foram menores que a da aveia-preta; o cultivo consorciado de tremoço-branco, caupi e a aveia-preta transferiram 18, 17 e 7% de N para a alface; e que em cultivo consorciado há transferência de N proveniente da fixação biológica do nitrogênio (FBN) dos adubos verdes tremoço-branco e caupi para a alface.

The study aimed at evaluating and comparing changes provoked by the water deficit on water relations and nitrogen fixation in two Vigna unguiculata cultivars, as well as at indicating which cultivar is more tolerant under water deficiency. The experimental design used was entirely randomized in factorial scheme, with 2 cultivars (Pitiuba and Pérola) and 2 water regimes (control and stress). The parameters evaluated were the leaf relative water content, stomatal conductance, transpiration rate, nodule number, nodule dry matter, nitrate reductase enzyme activity, ureide concentration and leghemoglobin in nodule. The stomatal conductance of the Pitiuba and Pérola cultivars under water deficit were 0.20 and 0.01 mmol H2O/m2/s, respectively. The nitrate reductase activity of the plants under stress was significantly reduced in both cultivars. The leghemoglobin in the Pitiuba and Pérola cultivars under water stress had the concentrations of 58 and 41 g/kg dry matter, respectively. The parameters investigated in this study suggest that the Pitiuba cultivar under water deficit suffers from smaller changes, when compared with Pérola cultivar.

O trabalho objetivou avaliar o efeito de quatro doses de nitrogênio aplicadas no solo sobre o rendimento produtivo e a qualidade fisiológica de sementes do feijão-caupi, cv. BRS Mazagão. O experimento foi conduzido na fazenda Jabuti, em Boa Vista, de janeiro a março/2003, sob irrigação por pivô central. O delineamento utilizado foi o de blocos casualizados, com quatro tratamentos, constituídos das doses de nitrogênio (0; 20; 40; e 60 kg ha-1, utilizando uréia como fonte), aplicadas manualmente, em quatro repetições. Para as avaliações foram utilizadas parcelas de seis metros lineares por seis fileiras de plantas, semeadas mecanicamente, espaçadas de 0,45 m, com área útil de 3,6 m2. Para avaliar a qualidade fisiológica das sementes foi conduzido um experimento em laboratório com delineamento inteiramente casualizado, com quatro repetições de 50 sementes cada. Os resultados indicam que não houve efeito do nitrogênio aplicado sobre o número de grãos por vagem, enquanto o número de vagens e a massa de grãos aumentaram com as doses de nitrogênio. O nitrogênio aplicado ao solo proporcionou a produção de sementes mais vigorosas, ocorrendo aumento linear da emergência das sementes em campo com elevação de suas doses, passando a emergência média de 88% para 94%. A produtividade máxima de grãos (1.497 kg ha-1) foi obtida com a aplicação de 60 kg ha-1 de nitrogênio. A germinação das sementes não aumentou em função da elevação das doses de nitrogênio, apresentando uma taxa média de 91%. = An experiment was carried out to evaluate the effect of levels of nitrogen application on productive yield and physiological quality of cowpea seeds, cv. Mazagão. The experiment took place at Jabuti farm, in Brazil, from January to March/2003, under a central pivot irrigation system. The experimental design was completely randomized blocks, with four treatments consisting on nitrogen levels (0; 20; 40 and 60 kg ha-1, utilizing urea as N source) applied manually, with four replications. Each plot was 6 m long, with six lines of plants 0,45 m apart one from the other; the plants were mechanically sowed; the measuring area of the plot was 3,6 m2. The physiological quality of the seeds was assessed through an experiment conducted in laboratory conditions, in an entirely randomized design, with 4 replicates of 50 seeds each. The results indicate that there was no effect of applied N on number of grain per pod, whereas the number of pods and grain mass increased with N doses. N applied to soil provided a production of more vigorous seeds, occurring a linear increase in field seedling emergency with increase of its doses, the average seedling emergency altering from 88% to 94%. Maximum grain productivity (1.497 kg ha-1) was obtained with the application of 60 kg ha-1 of nitrogen. The seed germination rate did not increase as related to the elevation of N doses applied to the soil, showing a mean rate of 91%.

Estimating genetic parameters in plant breeding allows us to know the population potential for selecting and designing strategies that can maximize the achievement of superior genotypes. The objective of this study was to evaluate the genetic potential of a population of 20 cowpea genotypes by estimating genetic parameters and path analysis among the traits to guide the selection strategies. The trial was conducted in randomized block design with four replications. Its morphophysiological components, components of green grain production and dry grain yield were estimated from genetic use and correlations between the traits. Phenotypic correlations were deployed through path analysis into direct and indirect effects of morphophysiological traits and yield components on dry grain yield. There were significant differences (P < 0.01) between the genotypes for most the traits, indicating the presence of genetic variability in the population and the possibility of practicing selection. The population presents the potential for future genetic breeding studies and is highly promising for the selection of traits dry grain yield, the number of grains per pod, and hundred grains mass. A number of grains per green pod is the main determinant trait of dry grain yield that is also influenced by the cultivar cycle and that the selection for the dry grain yield can be made indirectly by selecting the green pod mass and green pod length. [ABSTRACT FROM AUTHOR]

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The aim of this work was to evaluate the transfer of N via biological nitrogen fixation from green manures to intercropped lettuce using the 15N abundance method. The treatments consisted of lettuce with black oats, lettuce with cowpea, lettuce with white lupin and monocropped lettuce (control). Green manures were sown at two different times including the following: 60 days before transplanting of lettuce seedlings and simultaneous to transplanting of lettuce seedlings. N transfer was estimated using the natural 15N abundance method. It was observed that lettuce intercropped with green manures reached the same fresh mass of monocropped lettuce when the green manures were sown at the same time as the vegetables were planted. However, when the green manures were sown previously, the fresh mass of the monocropped lettuce was higher, and independent of the sowing time of green manures, the monocropped lettuce reached a higher dry mass. White lupin and cowpea transferred higher amounts of N regardless of sowing time, and the C:N ratio of white lupin to cowpea was lower compared to black oats. Intercropping with white lupin, cowpea and black oat transferred 18, 17 and 7% of N, respectively, to lettuce. [ABSTRACT FROM AUTHOR]

Cowpea is an important legume in sub-Saharan Africa where its protein rich grains are consumed. Insect pests constitute a major constraint to cowpea production. Flower bud thrips (FTh) is the first major pest of cowpea at the reproductive stage and if not controlled with insecticides is capable of reducing grain yield significantly. Information on the inheritance of resistance to FTh is required to facilitate breeding of resistant cultivars. The genetics of resistance was studied in crosses of four cowpea lines. Maternal effect was implicated while frequency distributions of the F2 and backcross generations suggest quantitative inheritance. Additive, dominance and epistatic gene effects made large contributions and since improved inbred lines are the desired product, selection should not be too severe in the early generations to allow for desirable gene recombination. This study suggested that some of the genes involved in the control of resistance to FTh are different in TVu1509 and Sanzi. Broad sense heritability ranged from 56% to 73%. Choice of maternal parent in a cross will be critical to the success of resistance breeding. [ABSTRACT FROM AUTHOR]

To evaluate the impact of drought stress on the incidence of certain arthropod pests and their associated predators which inhabit cowpea plantations, field tests were conducted in two different levels of irrigation (10- and 20-day intervals) by using five newly produced cowpea cultivars. Results indicated that the main piercing and sucking pests Bemisia tabaci (Genn.) and Tetranychus urticae Koch. were represented in high numbers in stressed plantations when compared to non-stressed ones. On the other hand, the common predators associated with these pests had not been affected by these irrigation differences. Regarding to the damage percentage caused by the pod borer pest Etiella zinckenella Treitschke, an obvious increase was recorded on stressed plantations than on the normal irrigated ones in most of the tested cultivars. At harvest, the obtained results indicated an obvious decrease in the net yield income of all the tested cultivars in the stressed irrigated area than in normal irrigated one. Therefore, it must be recommended to irrigate cowpea plantations by at least 10-day intervals to avoid the high infestation by both of the sucking pests and pod borers, and also, to obtain high and good yield income. [ABSTRACT FROM AUTHOR]

This paper reviews accomplishments in cowpea cultivar and germplasm development by the Bean/Cowpea Collaborative Research Support Program (CRSP) which was funded by the United States Agency for International Development for a period of about 20 years. Drought-adapted, pest and disease resistant cultivars ‘Mouride’, ‘Melakh’ and ‘Ein El Gazal’ were developed for rainfed production in the tropical Sahelian zone of Africa. Cultivars ‘CRSP Nie´be´’ and ‘Lori Nie´be´’ which have seed and pod resistance to cowpea weevil and some disease resistance were developed for rainfed production in the tropical Savanna zone of West Africa. Cultivar ‘California Blackeye No. 27’ was developed for irrigated production in subtropical California, USA and is a semidwarf with heat tolerance and broad-based resistance to root-knot nematodes and Fusarium wilt. Various cultivars with persistent-green seed color including ‘Bettergreen’ and ‘Charleston Greenpack’ were bred for use in the food freezing industry in the USA. Germplasms were developed with unique traits including: snap-type pods, green manure/cover crop capabilities, heat tolerance during reproductive development, chilling tolerance during emergence, delayed leaf senescence as a mechanism of adaptation to mid-season drought and high grain yields, differences in stable carbon isotope discrimination, harvest index, rooting and plant water- and nutrient-relations traits, broad-based resistance to root-knot nematodes and Fusarium wilt, and resistance to flower thrips, cowpea aphid, lygus bug and cowpea weevil, and various quality traits including all-white and sweet grain. These germplasms provide a valuable resource for breeding additional cowpea cultivars for Africa and the USA. [Copyright &y& Elsevier]

A chimeric plant was observed in the F2 generation of a cross between a mutant cultivar, Ife BPC, and a germplasm line, TVu 2, in cowpea, Vigna unguiculata (L.) Walp. The chimeric plant had four lateral branches, one of which was intensely variegated, while the others were mostly green with few white sectors. F3 progeny from the intensely variegated branch of this plant were all variegated, while seed derived from the mostly green branches produced only green progeny. In subsequent generations, the descendants of the variegated branch bred true for the variegated trait, while those of the mostly green branches were also true-breeding for green colour. No pure-green or pure-white shoots were observed in any of the variegated plants examined in this study. Consequently, no pure-green or pure-white seedlings were produced from seeds harvested from the variegated plants. The results of reciprocal crosses between variegated and normal green plants indicate that variegation is inherited in a strictly uniparental maternal fashion. This is the first report of a cytoplasmically inherited mutation affecting foliage colour in cowpea. [ABSTRACT FROM AUTHOR]