Cowpea Seeds Research Articles

Antibacterial Peptides Produced by Alcalase from Cowpea Seed Proteins.

Cowpea seed protein hydrolysates (CPH) were output from cowpea seeds applying alcalase® from Bacillus licheniformis. CPH with an elevated level of hydrolysis was fractionated by size exclusion chromatography (SEC). Both CPH and SEC-portions showed to contain antimicrobial peptides (AMPs) as they inhibited both Gram-positive bacteria, such as Listeria monocytogenes LMG10470 (L. monocytogenes), Listeria innocua. LMG11387 (L. innocua), Staphylococcus aureus ATCC25923 (S.aureus), and Streptococcus pyogenes ATCC19615 (St.pyogenes), and Gram-negative bacteria, such as Klebsiella pnemoniae ATCC43816 (K. pnemoniae), Pseudomonas aeroginosa ATCC26853 (P. aeroginosa), Escherichia coli ATCC25468) (E.coli) and Salmonella typhimurium ATCC14028 (S. typhimurium).The data exhibited that both CPH and size exclusion chromatography-fraction 1 (SEC-F1) showed high antibacterial efficiency versus almost all the assessed bacteria. The MIC of the AMPs within SEC-F1 and CPHs were (25 µg/mL) against P. aeruginosa, E.coli and St. pyogenes. However, higher MICsof approximately 100–150 µg/mL showed for both CPHs and SEC-F1 against both S. aureus and L. innocua; it was 50 µg/mL of CPH against S.aureus. The Electro-spray-ionization-mass-spectrometry (ESI-MS) of fraction (1) revealed 10 dipeptides with a molecular masses arranged from 184 Da to 364 Da and one Penta peptide with a molecular mass of approximately 659 Da inthe case of positive ions. While the negative ions showed 4 dipeptides with the molecular masses that arranged from 330 Da to 373 Da. Transmission electron microscope (TEM) demonstrated that the SEC-F1 induced changes in the bacterial cells affected. Thus, the results suggested that the hydrolysis of cowpea seed proteins by Alcalase is an uncomplicated appliance to intensify its antibacterial efficiency.

Cantharis 200c counters heat stress in germinating seeds of Vigna unguiculata (L.) Walp.

Background
 Thermal stress during early imbibitional phase of germination causes disruption of redox-homeostasis by increasing accumulation of ROS Reactive Oxygen species (assessed in terms of hydrogen peroxide) and significant reduction of antioxidative defense (assessed in terms of catalase and peroxidase) in germinating tissues of cowpea (Vigna ungiculata). It also induces oxidative damage to newly assembled membrane system by aggravating membrane lipid peroxidation [measured in terms of thiobarbituric acid reactive substances (TBARS)]. Cantharis is a homeopathic remedy used for treating burn injuries in humans. The objective is to see whether potentized Cantharis could ameliorate heat stress in germinating seeds of cowpea.
 
 Methodology
 Seeds, imbibed in water overnight, were divided into four groups (n=50/group): Control I (Water 200c), Control II (Ethanol 200c), treated with Cantharis 200c and untreated and unstressed. Water soaked seeds were dipped in control/drug solution for 5 min and then washed. Control II and Cantharis 200c were diluted with water 1:1000 to minimize the ethanol effect. Except the fourth group, all other groups were subjected to heat stress (450C for 8 hours). All the groups were allowed to germinate for 5 days in germination chamber at 25 ± 20C. Groups 1 and 2 (Control I and II) served as systematic negative controls throughout the experiment. Ten independent replications were performed for each group in parallel. All experiments were randomized and blinded. 
 
 
 Results
 The systematic negative controls (I, II) did not produce any significant effect. The results in terms of germination, growth, soluble sugar, protein, accumulation of reactive oxygen species and loss of membrane permeability clearly exhibit that Cantharis 200c could mitigate heat stress significantly (p

Interactive Influence of Location and Variety on Physiological Quality of Cowpea Seeds (Vigna unguiculata (L) Walp.)

The production environment plays a significant role in the production of high-quality seeds. Therefore, the knowledge of the relative contributions of the different factors that impact seed quality will be important for the management of seed production. The objective of this study was to assess the relative contribution of location and variety to the physiological quality of the cowpea seeds. Seeds of two varieties of cowpea, IT97K-918-118 and 977K-1499-35 were produced at three locations: Ikenne, Ilora, and Ballah. Hundred seed weight, seed moisture content, standard germination, accelerated ageing germination and electrical conductivity tests were carried out on the seeds. The results indicated that the location effect was highly significant (P<0.05) for hundred seed weight, germination percentage, germination rate index, accelerated ageing germination percentage and accelerated ageing germination rate index, while the varietal effect was highly significant for only hundred seed weight. However, location alone contributed more than 50% to the observed variability in hundred seed weight, germination percentage, germination rate index and accelerated ageing germination percentage. Seeds from Ballah had the highest viability (germination percentage = 84.67%) but also the lowest vigour (accelerated ageing germination = 11%; electrical conductivity = 64.10µscm-1g-1). Thus, the modulating effect of the environment on the quality of cowpea seeds is not the same for the different components of quality and the choice of location for the production of cowpea seeds should be given a higher priority than a choice of variety per se.

Optimization of Cowpea Productivity and Seed Quality under Soil Natural Salinity Stress Using some Different Protective Treatments تحسين انتاجية وجودة بذور اللوبيا تحت إجهاد ملوحة التربة الطبيعية باستخدام بعض المعالجات المختلفة

This study was conducted with the aim is amelioration salinity stress and optimizes flowering, seed productivity and quality of cowpea(Kaha 1)under the stress of natural soil salinity using some different treatments during both successive seasons 2018-2019. The seeds of seed priming were grown under the same levels of natural saline stress, medium (5 dS/m) and high 7 dS/m) in two fields of El-Serw Agricultural Research Center, Damietta governorate. Sulfur (0.4 ton/fed.) and sulfuric acid (10 L/fed.)as soil amendments and chitosan (0.2 g/L), potassium silicate(1.1 g/L), and yeast extract (20 g/L)as different foliar applications in addition to untreated control. The layout of the current experiment was planned as split-split plot design in a completely randomized blocks design. The results conducted into a negative feedback of salinity stress on flowering, dry yield productivity and seed quality in comparing to improved ones by soil amendments or foliar applications. The major interaction in optimization flowering, dry yield and quality was less level of salinity stress (5 dS/m) interacted with mixed treatment between sulfur (0.4 ton/fed.), followed by sulfuric acid (10 L/fed.)amended with soil and sprayed with chitosan (0.2 g/L) or by yeast extract (20 g/L).Therefore, we recommend adding sulfur to the soil (0.4 ton/fed.) before planting as well as spraying plants with chitosan (0.2 g/l) or spraying with yeast extract (20 g/l) after 20 days of planting 3 times every 10 days to increase plant tolerance on soil salinity to obtain the best flowering, seed productivity and the highest quality under the same conditions.

Alleviation of Natural Salinity Stress on Seedlings and Growth of Cowpea Plants Using Some Different Protective Treatments تفادي تأثير الإجهاد الملحي الطبيعي علي إنبات ونمو نباتات اللوبيا باستخدام بعض المعالجات المختلفة

The current research was conducted to alleviate natural salinity stress on seed germination by seed priming and within turn on vegetative development using some different treatments. In laboratory, Seeds were soaked in chitosan (0.2 g/L), potassium silicate (1.1 g/L), and yeast extract (20 g/L) compared to control treatment for 3½ hours under different salinity stress (0, 5 and 7 dS/m)for 3½ with. Previous seeds were planted under the same levels of natural saline stress in two fields of the Agricultural Research Center in Damietta governorate, during 2018-2019 seasons. Two types of treatments were used, sulfur (0.4 ton/fed.) and sulfuric acid (10 L/ fed.) as soil amendments and the same previous soaking compounds used to seed priming as foliar application treatments. Results reveal that elevated the salinity stress had a negative feedback on cowpea seedlings and growth traits. Meanwhile, each of chosen protective treatments had significantly improvement of seed priming and vegetative growth traits. The major improved interaction for the formerly characteristics was the combined addition of sulphur in soil with spraying chitosan or with yeast extract under natural salinity stress. Therefore, we recommend adding sulfur to the soil (0.4 ton/fed.) before cultivation and soaking the seeds of cowpea (Kaha 1) to prepare it for germination (Seed priming) as well as spraying plants by chitosan (0.2 g/l) or spraying with yeast extract (20 g/l) after 20 days after sowing, three times, ten days intervals, to increase plant tolerance to natural soil salinity for obtain the best vegetable growth under the same conditions.

ANALISIS LINTAS PERTUMBUHAN DAN PRODUKSI TERHADAP PROTEIN KACANG TUNGGAK (Vigna unguiculata L) GENERASI M2

Cowpea (V. unguiculata L) can be developed as a source of vegetable protein because it contains relatively high protein and high lysine. The protein content in seeds is an accumulation of character components that play a role in protein formation, whose relationship can be predicted using cross correlation and analysis coefficients. The study was carried out in the experimental garden of Pasir Kuda PKHT of IPB in February - May 2018. Protein analysis is carriedout in the Testing Laboratory of the Department of Agronomy and Horticulture, Faculty of Agriculture, IPB in June - July 2018. The study was conducted using 30 putative mutant test genotypes of M2 generation result from the mutation of gamma ray irradiation and KM4 genotype as a comparison which was repeated three times. The protein content of the seeds was analyzed using the Kjeldahl method and then analyzed the variance, correlation coefficient and path. The results showed that M2 generation putative mutants showed diversity for the character of protein content in cowpea seeds. The protein content in cowpea seeds can be predicted through the character of plant height and number of branches.

Trehalose and proline failed to enhance cold tolerance of the cowpea weevil, Callosobruchus maculatus (F.) (Col.: Bruchidae)

The cowpea weevil, Callosobruchus maculatus (F.) (Col.: Bruchidae) is a cosmopolitan field-to-store pest ranked as the major post-harvest pest of cowpea in tropical regions. The cold tolerance of an insect species can vary as a result of abiotic features including food resources. In this study, C. maculatus larvae were fed with proline and trehalose (10, 20, and 40 mmol) treated cowpea seeds to determine the effects of these potential cryoprotectants on the supercooling (SCP) and cold hardiness of the upcoming adult beetles. The SCPs of the control, proline-fed and trehalose-fed adults non-significantly changed from −18.2 °C for the control to −17.2 °C for trehalose-fed adults. The cold hardiness (24 h at 0, -5.0, −7.5, −10.0, and −12.5 °C) of the adults was almost the same for control and treatments. Median lethal times (LT50; lethal time for 50% mortality) were 6.3, 6.0, and 5.4 h, respectively. Moreover, feeding the larvae with proline and trehalose-treated seeds did not affect the proline and trehalose contents of the adult beetles. Our results showed that C. maculatus could not tolerate subzero temperatures well above their SCP, indicating that this species might be a chill-susceptible insect.

Chemical and molecular examinations of some cowpea genotypes using simple sequence repeat and intersimple sequence repeat DNA markers in relation to their cooking quality.

Cowpea is a leguminous crop that has received widespread attention due to its high nutritional value. However, it is prone to losing some of its nutritional content due to the long cooking process. In this study, fourteen cowpea genotypes were evaluated for their chemical properties before and after cooking, along with the effect of different cooking treatments on the cooking time, considered as the main indicator of the cooking quality. Moreover, the correlation between molecular markers (simple sequence repeat (SSR) and intersimple sequence repeat (ISSR)) and the cooking time of cowpea genotypes was determined. The obtained results showed significant differences between all the investigated genotypes before and after the cooking procedure, reflecting significant genotypic and heritability estimates. Kareem 7 and Greenish Black Balady genotypes showed the shortest cooking time. Microwave's treatment manifested the shortest cooking time compared with the other treatments, which appeared as a new approach to improve the cooking quality of cowpea seeds. Spearman's rank correlation showed that the calculated values were smaller than the tabulated value at 0.05, reflecting the existence of a rank correlation between SSR/ISSR‐PCR banding products and the cooking time of cowpea genotypes. Such a study appeared to be a new approach, particularly in Egypt for the proper selection of the optimal cowpea seed on the basis of its cooking quality.

Multichannel imaging for monitoring chemical composition and germination capacity of cowpea (Vigna unguiculata) seeds during development and maturation

This study aimed to set a computer-integrated multichannel spectral imaging system as a high-throughput phenotyping tool for the analysis of individual cowpea seeds harvested at different developmental stages. The changes in germination capacity and variations in moisture, protein and different sugars during twelve stages of seed development from 10 to 32 days after anthesis were non-destructively monitored. Multispectral data at 20 discrete wavelengths in the ultraviolet, visible and near infrared regions were extracted from individual seeds and then modelled using partial least squares regression and linear discriminant analysis (LDA) models. The developed multivariate models were accurate enough for monitoring all possible changes occurred in moisture, protein and sugar contents with coefficients of determination in prediction Rp2 of 0.93, 0.80 and 0.78 and root mean square errors in prediction (RMSEP) of 6.045%, 2.236% and 0.890%, respectively. The accuracy of PLS models in predicting individual sugars such as verbascose and stachyose was reasonable with Rp2 of 0.87 and 0.87 and RMSEP of 0.071% and 0.485%, respectively; but for the prediction of sucrose and raffinose the accuracy was relatively limited with Rp2 of 0.24 and 0.66 and RMSEP of 0.567% and 0.045%, respectively. The developed LDA model was robust in classifying the seeds based on their germination capacity with overall correct classification of 96.33% and 95.67% in the training and validation datasets, respectively. With these levels of accuracy, the proposed multichannel spectral imaging system designed for single seeds could be an effective choice as a rapid screening and non-destructive technique for identifying the ideal harvesting time of cowpea seeds based on their chemical composition and germination capacity. Moreover, the development of chemical images of the major constituents along with classification images confirmed the usefulness of the proposed technique as a non-destructive tool for estimating the concentrations and spatial distributions of moisture, protein and sugars during different developmental stages of cowpea seeds.

VARIABILITY OF MACRO- AND MICROELEMENT COMPOSITION OF ACCESSIONS OF VIGNA UNGUICULATA (L.) WALP. IN THE SOUTH OF WESTERN SIBERIA AND IN THE CRIMEA

Different environmental factors can cause changes in the elemental composition of plants. The research attempts to shift the focus from studying the effect of soil on the elemental composition of plants to assessing the impact of multifactorial ecological blocks on this index. Using the method of atomic absorption spectroscopy, the content K, Na, Ca, Mg, Fe, Zn, Cu, Mn, Co, Li was determined in the seeds of 5 accessions of a new for Russia crop − vigna (Vigna unguiculata) when growing plants in the south of Western Siberia (54° N 83° E) and in the Crimea (44° N, 34° E)]. The Coefficient of Variation (CV) of the element contents in cowpea accessions in two regions was significant − from 14 to 53%. The highest homeostasis in the accumulation of macro- and microelements was noted in the cultivar Sibirskiy razmer (CV = 15–23%), macroelements − Vigna catjang (CV = 14%). Both accessions were characterized by a reduced accumulation of K, Na, Mg, Mn and, especially, Fe compared to other cultivars. The rest of the accessions showed a high rate of variation in the elemental composition under different conditions (CV = 29–53%). K, Mg, Ca, Zn, and Mn differed by a relatively lower variability of accumulation in cowpea seeds – both by the accessions and the regions of cultivation, while Na, Co, Li, and Cu was the highest. Cultivar Yunnanskaya had the highest rates of Ca (882–1357 mg/kg) and Fe (96–196 mg/kg) accumulation in both regions whereas accessions Krasnaya pozdniaya and Krasno-pestraya had the highest rate of Mg content − 1632–2131 and 1737–1986 mg/kg, respectively.

Effect of cashew (Anacardium occidentale) nut shell stored and fresh extracts on cowpea bruchid, Callosobruchus maculatus (Fabricius.) (Coleoptera: Chrysomelidae)

Effect of cashew (Anacardium occidentale) nut shell stored and fresh extracts on cowpea bruchid, Callosobruchus maculatus (Fabricius.) (Coleoptera: Chrysomelidae)

EFFECT OF WEDELIA TRILOBATA ESSENTIAL OIL ON THE GERMINATION AND SEEDLING GROWTH OF COWPEA

Wedelia trilobata is an invasive weed of the family Asteraceae.Objective of the study was to find out the impact of essential oil on the germination and seedling growth of cowpea. Different concentrations of essential oil(200, 400, 600, 800 and 1000ppm) were used,a controlwas kept without oil. Cowpea seeds were sown in these essential oil in petriplates,at the end of test period all the germination parameters were measured. All the germination parameters showed that treatment had no negative impact on germination. While root length,shoot length,embryo axis length,seedling length showed a significant variation in treatments compared to control. GC-MS analysis of essential oil revealed that it is a mixed chemotype and α-pinene (10.859 %), caryophyllene oxide (5.325%) and spathulenol (7.911%) are the major compounds.

Design and simulation analysis of cowpea dehulling Machine

The dehulling of cowpea seeds will have a great influence in increasing the overall production, consumption, processing into more dietary, hygienic products and the advancement of cowpea processing industry. The technology of cowpea processing industry is still at its lowest ebb. Therefore, designing a machine to dehull cowpea beans would be of greater benefit to the common man protein intake and the afore-mentioned development of the cowpea industry. The machine is designed to be mechanically operated by an electric motor as the prime mover with dehulling capacity of 6.67x10-4m3/s or 37.2kg/min. The beans will be fed by rotating force received from the feed wheel in the hopper into the plate's gap interface that will be pre-set that the total volume of feeder is approximately the volume of the space between plate surfaces. The rotating action of moving against stationary plate effect the rasping of soaked cowpea off their cotyledons. The design consideration applied appropriate technology, ease of dehulling soaked cowpea and the attrition action of plate surfaces and readily available engineering materials with possible equipment in the country. The dehulled efficiency was 79% at 81.25% machine efficiency shown from the simulation analysis, this greatly show a high level improvement when compared with other related designs.

Impact of sublethal doses of Piper guineense (Schum and Thonn) on the biological parameters of Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae) reared on different cowpea varieties

• The response of C . maculatus to P . guineense was influenced by the variety of the stock culture. • Fecundity, hatchability, and survival differed among the exposed varietal populations. • Oviposition and hatchability index of C. maculatus postively correlated with the cowpea varieties. • Varietal difference, and not just exposure to sublethal doses of P. guineense , explained observed response. • Thus, white cowpea seeds predisposed C. maculatus to sublethal effects of P. guineense than colored seeds. Cowpea varieties show a wide range of characteristics in their composition that can determine Callosobruchus maculatus (Fabricius) response and survival. Consequently, this work investigated the influence of sublethal doses of Piper guineense on C. maculatus raised on four cowpea varieties: ART-98–12, Niger White, Oloyin, and Ife Brown. Our results demonstrated that C. maculatus from different varieties, despite being reared under the same conditions, responded differently to sublethal doses of P. guineense . Cowpea beetles from ART-98–12 were the most susceptible while those reared on Ife Brown were the least susceptible. Across varieties, survival and reproductive parameters of C. maculatus differed. Furthermore, the ranking for the percentage reduction in the number of eggs laid by C. maculatus was ART-98–12 > Niger White > Oloyin > Ife Brown. According to the log-rank statistic test, the difference observed in C. maculatus ’ survival can be explained by variety (log-rank statistic: χ2 [df = 3, N = 16] = 15, p = 0.004). Conversely, the survivability of the chrysomelid beetles reared on Niger white was significantly lower (p = 0.012) compared to the other varieties. This study highlights the role of cowpea variety in dictating the efficacy of a given botanical against C. maculatus .

Insecticidal Activity of Powder and Essential Oils of Vepris heterophylla (Rutaceae) and Syzygium aromaticum (Mytaceae) Towards Callosobruchus maculatus F. walp (Coleoptera: Bruchidae) on Post-Harvest Vigna unguiculata (Fabaceae) in the Far-North Region of Cameroon

The bioinsecticidal effect of powders and essential oils of S. aromaticum (L.) flower buds and V. heterophylla (Engl.) leaves against adult cowpea weevil C. maculatus was studied. Powders were tested by direct contact only while essential oils were tested by direct contact and indirect contact (inhalation and repellency). In 500 mL glass jars, the individual and combined powders were applied to 100 g of cowpea seeds at 0.5 g, 1 g, 1.5 g and 2 g doses for both leaves and flower buds of V. heterophylla and S. aromaticum respectively. The essential oils were also applied individually and after equilibrium combination on 50 g of cowpea at 4 µL/mL, 8 µL/mL, 12 µL/mL, 16 µL/mL. All the infestations were then achieved by adding 20 bruchids of 48 h old. The essential oil obtained was purified and analyzed with Gas Chromatography and Mass Spectrometry (GC-MS). 72 h after the individual treatment, 100% mortality was obtained at 2 g dose for V. heterophylla and 0.5 g dose for S. aromaticum compared to the control jars (1%). The combined powders were found to be more effective with 100% of mortality at a dose 1 g after 48 h of exposure. For essential oils, 100% and 90% of mortality were obtained respectively at 8 µL/mL dose for S. aromaticum (160 µL/kg) and 16 µL/mL dose for V. heterophylla (320 µL/kg) 72 h after treatment. In addition, the essential oil of S. aromaticum showed relatively higher repellant properties with an average repellency percentage of PR = 89.37% than that of V. heterophylla (PR = 70.62%). 100% of mortality was induced after inhalation of essential oils of S. aromaticum and V. heterophylla at doses 10 µL and 40 µL respectively after 72 h of exposure time. The results obtained from the GC-MS showed that the major components in the essential oil of S. aromaticum were eugenol (83.40%) although that of V. heterophylla were Spathulenol (23.66%), Beta-Caryophyllene oxide (16.46%) and 6-Isopropenyl-4 (16.30%). The powders and essential oils of the tested plants applied individually or after equilibrium combination showed interesting prospects for controlling Callosobruchus maculatus and effectively preserving cowpea seeds in storage warehouses.

Application of Trichoderma harzianum on the physiological quality of cowpea seeds

The use of fungi in seed treatment can improve the plant's physiological characteristics. The aim of this study was to evaluate the influence of the use of Trichoderma harzianum on the physiological quality of bean seeds. The experiment was set up and conducted in the forest seed laboratory of the Federal University of Western Para, in a randomized design, using 4 procedures on the basis of a colony forming unit (CFU): T1 (0 CFU), T2 (4 x 109 CFU), T3 (8 x 109 CFU) and T4 (12 x 109 CFU), with 5 repetitions. Germination percentage (G%), germination speed index (GSI), hypocotyl length (HL) and radicle length (RL) were evaluated as variables. The data were analyzed by variance analysis and the averages were compared using the Tukey test (p≤0.05), in addition to the regression analysis, using the Minitab© version 18 statistical software. There were differences between the germination percentage tests, in which T2 obtained 100% of germinated seeds, for GSI it was observed that T2 and T3 were equal and superior to the other treatments, while for RL T1 and T2 obtained the best results, however, for HL there were no statistical differences between treatments. T2 was more efficient in the physiological quality of seeds to germination percentage and germination speed index

CONDITIONING AND SAFE STORAGE OF COWPEA SEEDS USING PLASTIC HERMETIC BAGS

Most important feature of the storage systems is to preserve the integrity of the grain for a given period with minimal loss in quality and quantity. The main objective of this study aimed to choose the proper conditions which ensure safe storage process using infrared heating at the optimum radiation intensity of 882.67 W/m2 and exposure time of 15 min and the ultraviolet radiation at radiation intensity of 3.538 mW/cm2 and exposure time of 40 min on storability of cowpea seeds using different types of plastic hermetic bags in comparison with polypropylene (pp) woven bags. The changes in cowpea seeds quality during storage of pre-treated cowpea seeds in terms of moisture content, protein content, total microbial count and insect detection were also determined. The results show that, the moisture content of seeds stored in pp woven bags increased in contrast with both types of studied hermetic bags, oxygen concentration for hermetic bags decreased during storage period and carbon dioxide increased unlike pp woven bag, The rate of seeds infection with microorganisms and weevils was lower comparing with the samples stored in both types of hermetic bags and crude protein content of seeds stored in hermetic bags reduced at a very slight rate in comparison with that stored in woven bag.

Insecticidal efficacy of two inert dusts and Trichoderma harzianum, applied alone or in combination, against Callosobruchus maculatus and Callosobruchus chinensis on stored cowpea seeds

The insecticidal effect of Trichoderma harzianum (TH), diatomaceous earth (DE), kaolin (KA) and their combinations against Callosobruchus maculatus (F.) and Callosobruchus chinensis L. (Coleoptera: Chrysomelidae: Bruchinae) was evaluated. The fungus T. harzianum was applied at 1 × 105, 1 × 106 and 1 × 107 spores/kg of cowpea seeds individually and mixed with 100, 500 and 1000 mg/kg of DE or KA. The effect of individual and binary treatments on adult mortality after 3 and 7 days of exposure was determined. The progeny production of both insects and weight loss in cowpea seeds were assessed after 45 days of exposure. Complete adult mortality of both insect species was achieved by using the highest application rate of DE/TH mixture (1000 mg/kg of DE+1.0 × 107 spores/kg of TH) after 7 days. A mixture of KA/TH (1000 mg/kg of KA+1.0 × 107 spores/kg of TH) caused 100.0 and 97.9% mortality of C. maculatus and C. chinensis, respectively, after 7 days of exposure. Progeny production of both insect species was significantly decreased for all individual and combination treatments compared to the control. No progeny of C. chinensis was detected in cowpea seeds treated with the mixture 1000 mg/kg of KA+‏ 1.0 × 107 spores/kg of TH after 45 days. Also, the combination treatments protected cowpea seeds from damage caused by C. maculatus and C. chinensis for 45 days. These results indicate that the combinations of TH fungus with DE or KA could be successfully used for the management of C. maculatus and C. chinensis in stored cowpea seeds.

Extraction Treatments Affect Total Flavonoid and Phenolic Contents of Cowpea (Vigna Unguiculata L. Walp.)

Plant secondary metabolites exist during normal plant growth. The production increases remarkably when the plants are challenged by environmental stress. Quantification of these metabolites is affected by extraction solvents and preparation treatments. This study aims to select extraction solvents and treatments which are able to extract high total flavonoid and phenolic contents in cowpea seeds. Acetone at concentrations of 70-80% produced higher total flavonoid and phenolic contents of 10.37-11.93 mg CE/g and 18.20 – 20.20 mg GAE/g in two cowpea cultivars. Antioxidant activities were in the range from 115.9 to 126.1 umol TE/g. Extraction of cowpea seeds using 70% acidified acetone produced a similar amount of total phenolic contents to those of 70-80% acetone. Traditional extraction treatments of shaking and maceration extracted a similar amount of the secondary metabolites. These simple extraction methods, therefore, could be suggested to extract flavonoid and phenolic contents as well as antioxidant activity in cowpea where access to modern types of equipment is limited.

Thermal Preferences of Cowpea Seed Beetles (Callosobruchus maculatus): Effects of Sex and Nuptial Gift Transfers.

Simple SummaryThe thermal environment is crucial for organismal functioning, and many cold-blooded organisms, including insects, behaviorally regulate their body temperature. Why do insects inhabit given thermal conditions? We propose that access to water affects thermal preference and that insects with poor access to water inhabit colder environments, which reduces evaporation and preserves water. We studied the seed beetle Callosobruchus maculatus, which, as adults, do not drink or eat; however, males provide their mates with sperm, as well as nuptial gifts, including nutrients and water sources. We compared preferred temperatures between males and females that had access to mates or remained unmated and measured the sizes of the transferred gifts. We found that females preferred higher temperatures than males, but these preferences did not change due to mating or the transfer of larger or smaller gifts. It appears that males and females receive and lose certain amounts of water during mating, but they do not alter their thermal preferences according to the amount of water they receive or lose.The thermal environment influences insect performance, but the factors affecting insect thermal preferences are rarely studied. We studied Callosobruchus maculatus seed beetles and hypothesized that thermal preferences are influenced by water balance, with individuals with limited water reserves preferring cooler habitats to reduce evaporative water loss. Adult C. maculatus, in their flightless morph, do not consume food or water, but a copulating male provides a female with a nuptial gift of ejaculate containing nutrients and water. We hypothesized that gift recipients would prefer warmer habitats than gift donors and that both sexes would plastically adjust their thermal preferences according to the size of the transferred gift. We measured the thermal preference in each sex in individuals that were mated once or were unmated. In the mated group, we measured the sizes of the nuptial gifts and calculated proportional body mass changes in each mate during copulation. Supporting the role of water balance in thermal preference, females preferred warmer habitats than males. Nevertheless, thermal preferences in either sex were not affected by mating status or gift size. It is likely that high rates of mating and gift transfers in C. maculatus living under natural conditions promoted the evolution of constitutive sex-dependent thermal preferences.