Genetic Enhancement of Indigenous Cowpea with Gamma-Ray Induced Trait Variation

Production of cowpea (Vigna unguiculata (L.) Walp.), a staple legume crop in Sub-Saharan Africa, faces challenges due to biotic and abiotic constraints. Induced mutagenesis was deployed to create genetic variation in two cowpea varieties (KVX396-4-5-2D and Moussa local). The radio-sensitivity tests led to determe the lethal dose 50 (LD50) corresponding to 230 Gy and 220 Gy for KVX396-4-5-2D and Moussa local varieties, respectively. Dried seeds (M0) of each variety were gamma-ray irradiated with LD50 − 50, LD50 and LD50 + 50. M1 seeds were advanced to generate M2, M3 and M4 mutants using the single-seed-descent method. M4 mutant lines were evaluated in rain-fed conditions using a randomized complete block design to assess phenotypic differences. Data on seven qualitative and eleven quantitative traits were collected. The results indicated that the mutation induced variability in three qualitative traits: in KVX 396-4-5-2D mutant lines, with flower and seed color frequencies at 2.61% and 0.56% respectively, and pod dehiscence at a frequency of 0.24%. While in Moussa local mutants, a pod color changed at a frequency of 17%. ANOVA results revealed significant differences between mutants of both varieties for all quantitative traits, including photosynthetic parameters. Positive correlations were observed between leaf diameter and 100-seed weight, and between branch number and 100-seed weight. Hierarchical clustering revealed three clusters among KVX 396-4-5-2D mutants and six clusters among Moussa local mutants. Early maturity and high foliage were induced traits in Cluster 3 of KVX 396-4-5-2D mutants while high hundred-seed weight was induced in Cluster 6 of Moussa local mutants.

Genetic Diversity in Cowpea (Vigna unguiculata (L.) Walp) under Two Growing Conditions*

This study explores the use of genetic variability for advancing the genetic improvement of Cowpea (Vigna unguiculata (L.) Walp), particularly in response to insect infestation stress. Over a period spanning 2015 to 2017, forty accessions of cowpeas were evaluated to determine their variability under both insecticide spray and no insecticide spray conditions at the Teachings and Research Farms, Federal University of Agriculture, Abeokuta. The experimental design was a randomized complete block design in three replicates. The accessions were evaluated for plant height, leaf length, leaf width, number of days of 50% flowering, number of pods per plant, pod length, number of seeds per plant, 100-seed weight, and seed yield. Data collected were subjected to principal component and single linkage cluster analyses. Principal axis I (PCA1) accounted for 39% and 35% under insecticide spray and no insecticide spray respectively to the total variation in the accessions. Plant height with a factor score of 0.38, leaf length (0.41), number of leaves (0.37), and 100-seed, weight (0.30) was related to PCAI under insecticide spray while leaf width (0.32). Pod length (0.37) and number of seeds/plant (0.38) were significant to PCA1 under no insecticide spray. Notably, accessions such as SAMPEA6, SAMPEA10, IFE-Brown, and IFE-BPE exhibited consistent performance across both conditions, while others displayed condition-specific attributes. For instance, NGB1063, NGB1152, and NGB1093 demonstrated distinct traits under insecticide spray, while NGB1146 and NGB1124 exhibited notable characteristics under no insecticide spray conditions. Therefore, identifying these forty accessions with desirable traits hold promise for future genetic improvement efforts of cowpea cultivation in Nigeria and beyond.

Efficiency of Botanical and Chemical Pesticides on the Control of Field Insect Pests under Cowpea Production

The pulse cowpea [Vigna unguiculata (L.) Walp] holds a significant agricultural position in Uganda, ranking fourth among legume crops, following common beans, groundnuts, and soybeans. Known for its versatility, cowpeas are consumable at various developmental stages, from early seedling to maturity. However, the crop faces persistent pest challenges at each stage, leading to substantial yield losses. In Uganda, chemical insecticides are the primary pest control means, but their increased and excessive use raises environmental, health, and economic concerns. This has prompted a quest for alternative and sustainable solutions, prompting an exploration of botanical insecticides. This study, conducted at Makerere University Agricultural Research Institute (MUARIK), aimed to evaluate the effectiveness of three selected botanical insecticides versus four established chemical insecticides for managing cowpea insect pests under field conditions. The treatments included: Carbofuran, Cypermethrin 10% EC, Dimethoate, Pestwin, Pyrethrum ewc , Pyrethrum 5ew, Profenofos 40% Cypermethrin 4% EC mix, and Untreated, arranged in a randomized complete block design with three replications. The significant pests studied were aphids, thrips, pod-sucking bugs, and legume pod borer. Results indicated substantial impacts of the treatments on pest infestation, with Profenofos 40% Cypermethrin 4% EC being the most effective against most pests. The plant parameter, plant height, was significantly affected by treatments in 2016B, while the number of pods was impacted in 2017A. Pestwin, a botanical insecticide blend (containing Azadirachtin indica, Pongamia pinnata, and Ricinus communis extracts) demonstrated superior efficacy against cowpea aphids. Moreover, it positively influenced plant height, number of pods, and pod biomass, surpassing many chemical insecticides. Pestwin’s environmental friendliness positions it as a potential contributor to reducing environmental pollution, making it a promising candidate for inclusion in IPM programs. Overall, the study underscores the importance of exploring botanical alternatives to chemical insecticides for sustainable pest management in cowpea cultivation.

Near Infrared Spectroscopy (NIRS) Model-Based Prediction for Protein Content in Cowpea

Cowpea (Vigna unguiculata L. Walp) is a multi-purpose legume with high quality protein for human consumption and livestock. The objective of this work was to develop near-infrared spectroscopy (NIRS) prediction models to estimate protein content in cowpea. A total of 116 cowpea breeding lines with a wide range of protein contents (19.28 % to 32.04%) were selected to build the model using whole seed and ground seed samples. Partial least-squares discriminant analysis (PLS-DA) regression technique with different pre-treatments (derivatives, standard normal variate, and multiplicative scatter correction) were carried out to develop the protein prediction model. Results showed: 1) spectral plots of both the whole seed and ground seed showed higher spectral scatter at higher wavelengths (>1450 nm), 2) data pre-processing affects prediction accuracy for bot whole seed and ground seed samples, 3) prediction using ground seed samples (0.64 R2 0.85) is better than the whole seed (0.33 R2 0.78), and 4) the data pre-processing second derivative with standard normal variate has the best prediction (R2_whole seed = 0.78, R2_ground seed = 0.85). The results will be of interest in cowpea breeding programs aimed at improving total seed protein content.

Reactions of Maruca Resistant Transgenic Cowpea to Cowpea Aphid-Borne Mosaic Virus

Cowpea (Vigna unguiculata L. [Walp.]) in one of the main grain legumes contributing to food security and poverty alleviation in Sub-Saharan Africa. To control the highly damaging legume pod borer Maruca vitrata F., transgenic cowpea lines expressing the insecticidal Cry1Ab Bt protein were developed. In this study, we evaluated the impact of Cry1Ab transgene expression on the susceptibility of four cowpea lines (named IT97K-T, IT98K-T, Gourgou-T and Nafi-T) and their respective non-transgenic near isogenic lines (IT97K, IT98K, Gourgou and Nafi) to Cowpea aphid-borne mosaic virus (CABMV) in greenhouse conditions. In a preliminary quality control test by enzyme-linked immunosorbent assay, the presence of Cry1Ab protein in transgenic seed lots ranged from 59% to 72%, with no significant differences among the lines (χ2 = 3.26;p = 0.35). Upon virus inoculation, all cowpea lines exhibited mosaic symptoms with similar severity between 7- and 11-day post-inoculation. No significant differences were observed in symptom severity. Significant differences were found between cowpea lines for time of symptom onset, virus accumulation in plants and days to 50% flowering. However, while comparing pairs of transgenic lines and corresponding non-transgenic lines, virus accumulation showed not significant differences whatever the pair. Time of symptom onset and days to 50% flowering did not also differ significantly between pairs of cowpea lines except Nafi/Nafi-T in which transgenic Nafi-T showed earlier symptoms (7.4 ± 0.7 vs. 8.9 ± 0.8 days post-inoculation) and shorter flowering time (37.3 ± 0.6 vs. 42 ± 1.7 days after sowing). Overall, these findings improve our understanding of the effects of Cry1Ab gene mediated genetic modification on cowpea infection by Cowpea aphid-borne mosaic virus, with potential implications for environmental safety assessment.

Local Criteria Used by Farmers to Evaluate the Agronomic Performance and the Fertilizing Capacity of Cowpea Varieties: Diversity, Variability and Proximal Relation with Agronomic Measurements in Contrasted Sahelian Locations

When contributing to participatory research, farmers usually appreciate the performance of cowpea varieties using qualitative scores. The score they attribute to each variety are based on local knowledge. The specific criteria they individually use to attribute a score are not well described. The objectives of this work were to: 1) identify and describe exhaustively the local criteria used by farmers to measure the agronomic performance of cowpea;2) assess the variability and statistical structure of these farmer criteria across local contexts;3) and analyze the association between these farmer criteria and the classical agronomic measurement. To achieve these objectives, an augmented block design was implemented across fifteen locations in the regions of Maradi, Dosso and Tillabéri, representing a diversity of local contexts. From a set of 36 cowpea varieties, fifteen varieties were sown per location, including five varieties (controls) common to all locations. In each location, two replicates were sown in randomized Fisher’s blocks. After agronomic measurement and participatory evaluation (scoring of varieties by farmers), a group survey (focus group) was conducted in each location to identify the criteria considered by farmers to found their discretional scoring of varieties during the participatory evaluation. The analysis of the data identified, across locations, thirteen criteria defined by farmers to characterize the agronomic performance of cowpea. Some of these criteria were different according to location. Farmers ranked the three varieties with the best performance for each agronomical trait (Top 3 varieties). A comparison of the farmer ranking with the ranking based on agronomic measurements revealed similarity and complementary between both methods. This study highlighted the importance of considering both local and scientific knowledge in local varietal evaluations.

Effects of fresh-cut and storage on glucosinolates profile using broccoli as a case study

Glucosinolates(GLS) contribute to the unique flavour, nutrition, and plant defence of the Cruciferous vegetables. Understanding the GLS changes through postharvest processing is essential for defined preservation. In this study, four different fresh-cut types, whole flower(W),floret(F), quarterly cut floret(QF) and shredded floret(FS) of broccoli, were stored for 0, 1, 2 and 3 day(s) to explore GLS responses to postharvest treatments. As a result, seven GLS were identified, mainly including glucoraphanin(RAA), neoglucobrassicin(NEO), and glucobrassicin(GBC)and accounting for 52.69%, 20.12% and 14.99% of the total GLS(21.92 ± 0.48) μmol · g ^(-1 )DW, respectively. FS had the sharpest decrease in GLS after three days of storage(6.55 ± 0.37) μmol · g-1DW, while QF had the least(10.16 ± 0.33) μmol · g ^(-1 )DW. All GLS components decreased over storage, except for 4-methoxyglucobrassicin(4 ME) in FS and QF, suggesting its key role in serious wound defence. The results suggested certain postharvest approaches influenced the flavour and nutrition of broccoli.

我国豇豆蓟马研究进展及综合防控措施

豇豆Vigna unguiculata喜温喜光,是一种适合在我国南方种植的豆科蔬菜。长期以来,豇豆病虫害多发重发,其中,蓟马是豇豆上最主要和最顽固的害虫之一。传统的化学防治方法对蓟马的防治效果常常不理想,并易造成农药残留问题。本文概述了我国豇豆产业的种植情况和以蓟马为主的病虫害问题及豇豆蓟马研究现状,并从农艺措施、理化诱控、生物防治、化学防治和抗性治理角度总结了豇豆蓟马的综合防治技术。最后,从构建豇豆蓟马的有害生物综合治理(integrated pest management,IPM)技术体系、加强基础研究和防控技术产品开发、建立科学用药和农药监管制度3个方面提出建议,以期为我国豇豆产业的绿色可持续发展提供参考。

Protein Profiles of Pod Borer Maruca Resistant Transgenic Cowpea

The grain legume cowpea Vigna unguiculata (L.) Walp. is a major protein source used for food and feed in Sub-Saharan Africa. The crop is affected by the pod borer Maruca vitrata against which transgenic lines were developed as part of the genetic control approach. This study aimed to assess the protein profiles in seeds and leaves of transgenic cowpea lines and their non-transgenic near-isogenic counterparts. Crude protein content was determined by the Kjeldahl method, and soluble proteins were quantified using Bradford dye binding assay. The average crude protein content ranged between 21.61% and 26.58% in the seeds and between 10.86% and 17.90% in the leaves. Total solubility varied between 13.03% and 20.64%. Osborne’s protein fractions contents in the seeds were 52.41% - 69.52% (albumin), 4.62% - 7.19% (globulin), 7.95% - 11.40% (glutelin) and 3% - 4% (prolamin). In any case, protein content differed significantly between cowpea genotypes but not between pairs of transgenic/non-transgenic lines. Insecticidal Cry1Ab protein expressed by transgenic lines was only detected in the albumin and globulin fractions. Altogether, these findings enhance our understanding of the effects of genetic modification on cowpea protein content and composition, with potential implications for nutritional and safety assessments.

The El Niño-Southern Oscillation (ENSO) Effects on Cowpea and Winter Wheat Yields in the Semi-Arid Region of the Southern US

Information is limited on the effects of climate variability on cowpea (Vigna unguiculata L.) and winter wheat (Triticum aestivum L.) yields in the semiarid region of the southern US. Using the Decision Support System for Agrotechnology Transfer (DSSAT) crop model and weather data spanning 81 years, we assessed the impact of El Niño-Southern Oscillation (ENSO) on the grain yields of these crops in the Llano Estacado region of the southern US as affected by cowpea and wheat planting dates and N application rate. Simulated results showed that the El Niño phase of ENSO produced about 30% more yields of mono-cropped cowpea than those produced under the La Niña phase, especially with the cowpeas planted in July. The cowpea yields under El Niño were about 10% more than the 81-year average normal yield, whereas those under La Niña were about 20% less. At the N rates of 0, 50, and 100 kg·ha−1, regardless of wheat planting dates, the El Niño years produced, respectively, about 8%, 40%, and 60% higher wheat yields than those produced in the La Niña years, and about 5%, 20%, and 27% more than the 81-year average normal yield. In the La Niña years, the wheat yields at 0, 50, and 100 kg N ha−1 were, respectively, about 5%, 15%, and 20% less than the normal yield with similar N levels. The impact of ENSO on wheat yields under cowpea-wheat double-cropping systems was significant, especially for the wheat crops planted on October 15 (October 30) or later following the cowpea crops planted in June (July). At zero N, the mono-cropped wheat yields were not impacted by ENSO due to N limitation. However, the double-cropped wheat yields were impacted by ENSO even when no N fertilizer was applied due to high soil N status caused by N transfer from cowpea stover residues and roots. Results indicated that management strategies need to be attentive to ENSO forecasts and adjust potential planting dates and N application rates with the ENSO phase to avert risks of crop failure and economic loss.

Screen House Assessment of Cowpea [(Vigna unguiculata (L.)] Genotypes for Drought Tolerance Using Selection Indices

Cowpea [Vigna unguiculata (L.)] is one of the most important arid legumes cultivated for pulse and forage production. Drought is one of the most damageable constraints to crop production impacting negatively food security. The potential of cowpea to address food security is well established. However, not much is known about the base index selection method in breeding cowpea for drought tolerance, which is important for yields. Consequently, the present study has been conducted to: 1) evaluate the yield performance of cowpea genotypes under artificial drought and well-watered condition, 2) ranke genotype performance using selection indices, and 3) assess relationship between agronomic traits and yield. The experiment was the 2 watering conditions laid out in a Randomized Complete Block Design (RCBD) with three replications. The experiment was carried out in pots under screen house at the Department of Horticulture at KNUST. The result showed that KPR1-96-73, Simbo, CZ06-4-16, Wilibaly and Agyenkwa were high yielding in well-water condition while Ghana Shoba, Sangaraka, Nketewade, Ghana Shoni and Korobalen were high yielding genotypes in water stress condition. The average yield reduction was 60.6% and 16% for grain and fodder yield respectively. The biplot displays revealed four groups among the genotypes tested which were based on their yielding capacity and drought tolerance. In cluster B high yielding and drought tolerant genotypes were identified, high yielding and drought susceptible have been identified in cluster A, low yielding and drought tolerant in cluster D, and lastly low yielding and drought susceptible in cluster C. Genotypes in cluster B were best due to the fact that it combines high yield and tolerance to drought. They were Ghana Shoni, Nketewade, Sangaraka and Ghana Shoba. These genotypes might be suitably employed in further drought tolerance breeding programs of cowpea. Significant relationships were observed between agronomic trait and yields under drought condition.

Selection of Cowpea [(Vigna unguiculata (L.) WALP] Genotypes for Drought Tolerance Using Selection Indices

Cowpea [(Vigna unguiculata (L.)] is one of the most important arid legumes cultivated for pulse and forage production. However, in cowpea, not much is known about the base index selection method in breeding for drought tolerance. Consequently, the present study has been conducted to: 1) evaluate the yield performance of cowpea genotypes under artificial drought and well-watered condition;2) develop a base index using multiple traits for ranking genotype performance. The experiment was a 25 × 2 factorial laid out in a Randomized Complete Block Design (RCBD) with three replications. The experiment was carried out in the screen house at the Department of Horticulture at KNUST. The result showed that KPR1-96-73, Simbo, CZ06-4-16, Wilibaly and Agyenkwa were high yielding in well-water condition while Ghana Shoba, Sangaraka, NKetewade, Ghana-Shoni and Korobalen were high yielding genotypes in water stress condition. The average yield reduction was 60.6% for grain respectively. The biplot displays revealed four groups among the genotypes tested which was based on their yielding capacity and drought tolerance. In cluster B high yielding and drought tolerant genotypes were identified, high yielding and drought susceptible have been identified in cluster A, low yielding and drought tolerant in cluster D, and lastly low yielding and drought susceptible in cluster C. Genotypes in cluster B, were the best due to the fact that it combines high yield and tolerance to drought. They were Ghana Shoni, Nketewade, Sangaraka and Ghana shoba. These genotypes might be suitably employed in further drought tolerance breeding program of cowpea.

Post-Harvest Fungi Associated with Cowpea (Vigna unguiculata L. Walp.) Seeds Produced in Burkina Faso

Cowpea is a very popular foodstuff among people in sub-Saharan Africa. In Burkina Faso, it is the main food legume, especially in rural areas. Its production is facing difficulties including post-harvest losses caused by fungi. Therefore, the objective of this study was to isolate and identify fungal strains associated with cowpea seeds produced in Burkina Faso. Thus, a total of 108 seed samples were collected in the three agro-ecological zones of Burkina Faso. The sanitary analysis of the seeds was carried out using the direct contact method. The isolation and purification of the isolates were performed on Potato Dextrose Agar medium while their identification was done through macroscopic and microscopic phenotypical characterization using different culture media (Potato Dextrose Agar (PDA), Malt Extract Agar (MEA) and Czapeck Dox Agar (CZA)) and different identification keys. A total of 10 fungal species were isolated, with predominance of Aspergillus flavus, Aspegillus niger, Macrophomina phaseolina, Fusarium oxysporium and Rhizopus sp. whose infection rates were 70.8% to 100% of seed samples. In addition to being present in all three zones, the infection rates of Aspergillus flavus (56.55%), Aspergillus niger (20.35%) and Rhizopus (32.80%) were higher in the Sahelian zone. In the Sudano-Sahelian zone, Macrophomina (50.66%) and Fusarium (18.88%) presented the highest infection rates, while Penicillium sp. showed the highest infection rate (2.84%) in the Sudanian zone. This finding demonstrated the necessity to improve post-harvest and conservation techniques of cowpea to limit crop losses and preserve the sanitary quality of this important foodstuff.

Effect of Magnetic Field Technology on Preservation Quality of Fresh-cut Apple

[Objectives]The paper was to study the effect of magnetic field technology on physicochemical properties of fresh-cut apple during storage.[Methods]Using fresh-cut apples as materials,magnetic field assisted refrigeration and conventional refrigeration control groups were set up,and the preservation effects of magnetic field assisted refrigeration on fresh-cut apples were tested by measuring the changes of microorganisms and physicochemical indicators.In this experiment,the conditions of magnetic field assisted refrigeration group was set as follows:temperature 4℃,magnetic field intensity 5 mT,static magnetic field,and storage for 6 d.[Results]At 6 d post storage,the weight loss rate,total number of colonies and total number of fungi of fresh-cut apples increased;the L value and hardness showed a downward trend;the soluble solid content first increased and then decreased;and the total acid decreased first and then increased.The above indicators in magnetic field assisted refrigeration group changed more gently than that in conventional refrigeration group.Compared with conventional assisted refrigeration,the weight loss rate of fresh-cut apples treated by magnetic field combined with 4℃refrigeration was reduced by 68.00%;the hardness was increased by 12.23%;the total number of colonies and total number of fungi were reduced by 64.15%and 37.50%;and the L value did not change much.High content of soluble solids and total acid was maintained.[Conclusions]Magnetic field assisted refrigeration delays quality deterioration of fresh-cut apples during storage,prolongs shelf life,and further improves their edible quality and commodity value.

Growth indices of seeds(maize and cowpea)grown in heavy metal contaminated soil treated with ginger extract

The consumption of maize and cowpea in Africa and developing countries is high,owing to the fact that they are readily available,coupled the with nutritional benefits they provide.Growth loss has been seen in crops cultivated on heavy metal polluted soils as a consequence of alterations in physiological and biochemical processes.This study was aimed at assessing the growth indices of seeds(maize and cowpea)grown on heavy metal contaminated soil treated with ginger extracts.The study adopted a Complete Randomized Design(CRD)in which growth indices of either maize or cowpea were examined from each crop type grown on soil without any pollutant or treatment and soils with metal pollutants;with or without treatment with ginger extracts in the individual experiments.Data were analyzed using ANOVA.The results showed that ginger extract induced oxidative stress on cowpea after 10 days of cultivation with root length significantly(P≤0.05)higher on the normal control-G-M and+L-G which recorded 7.60 and 7.3 cm respectively.Patterns of growth indices noticed after 30 and 40 days of cowpea cultivation were variable showing least growth in leaf development.Highest maize root(27.00 cm),shoot(8.85 cm)and leaf(25.25 cm)development were recorded in maize grown on soil without metal contamination but treated with ginger(+G-M-positive control)after days 10,40 and 40 after cultivation.It was observed that the soil contaminated with heavy metals affected the growth pattern of the crops thereby causing stunted growth,chlorosis,discoloration and wilting.It could be concluded that cowpea performed better in shoot of both treated and untreated soils even though the values were not significantly different from that of root and leaf while maize showed a decrease in shoot even though the values for root and leaf were not significantly different.

Evaluation of the Insecticidal Activity of Powders of Ageratum conyzoide L. Leaves and Roots of Securidaca longepedunculata Fresen on the Germination Rate of Cowpea Infected with Callosobruchus maculatus

Cowpea is a vegetable that contributes to food security in Guinea. Despite its importance, more than 30% of its production is lost between harvesting, storage and consumption. The main cowpea pest is Callosobruchus maculatus. The commonly used control strategy is essentially based on chemicals whose use is toxic, expensive and restrictive. In the search for alternatives to chemical control, this work was undertaken to evaluate the insecticidal potential of Ageratum conyzoid leaf powders and Securidaca longepedunculata roots. Powder toxicity and insecticidal efficacy tests were performed separately on groups of 20 Callosobruchus maculatus using 3 doses of Ageratum conyzoid leaf powders and Securidaca longepedunculata roots in jars each containing 100 g cowpea. The mortality of Callosobruchus maculatus and the impact of powders were noted respectively for 96 h and 4 months after infestation. The germination capacity of the treated seeds was assessed at the start of the study. Doses of 1 and 8 g of Ageratum conyzoides leaf powders and Securidaca longepedunculata roots were applied respectively to every 100 g of cowpea and led to 100% mortality of Callosobruchus maculatus. At these same doses, more than half of the treated seeds were attacked during the 4 months of storage. Germination tests have shown that powders of Ageratum conyzoides leaves and roots of Securidaca longepedunculata have no negative effect on the germination power of cowpea seeds. Therefore, they could be considered as excellent bio-insecticides that socio-professional strata (farmers and warehouse workers) can use in the fight against cowpea insects intended for storage.

Exploring the Potential of Cowpea-Wheat Double Cropping in the Semi-Arid Region of the Southern United States Using the DSSAT Crop Model

Information is limited on the potential of double-cropping cowpea (Vigna unguiculata L.) and wheat (Triticum aestivum L.) in the semiarid region of the southern United States. Using the Decision Support System for Agrotechnology Transfer (DSSAT) crop model and weather data of 80 years, we assessed the possibility of cowpea-wheat double-cropping in this region for grain purpose as affected by planting date and N application rate. Results showed that the possibility of double-cropping varied from 0% to 65%, depending on the cropping system. The possibility was less with systems comprising earlier planting dates of wheat and later planting dates of cowpea. Results indicated that cowpea-wheat double-cropping could be beneficial only when no N was applied, with wheat planted on October 15 or later. At zero N, the double-crops of cowpea planted on July 15 and wheat planted on November 30 were the most beneficial of all the 72 double-cropping systems studied. With a delay in planting cowpea, the percentage of beneficial double-cropping systems decreased. At N rates other than zero, fallow-wheat monocropping systems were more beneficial than cowpea-wheat double-cropping systems, and the benefit was greater at a higher N rate. At 100 kg N ha-1, the monocrop of wheat planted on October 15 was the most beneficial of all the 94 systems studied. Results further showed that fallow-wheat yields increased almost linearly with an increase in N rate from 0 to 100 kg∙ha-1. Fallow-wheat grain yields were quadratically associated with planting dates. With an increase in N rate, wheat yields reached the peak with an earlier planting date. Wheat yields produced under monocropping systems were greater than those produced under double-cropping systems for any cowpea planting date. Cowpea yields produced under monocropping systems were greater than those produced under any double-cropping system. The relationship between cowpea grain yields and planting dates was quadratic, with July 1 planting date associated with the maximum yields.

浙江豇豆地方品种的遗传多样性

浙江省是我国豇豆的主要产区之一,为全面梳理、鉴定浙江省地方豇豆种质资源,对浙江省历年来收集到的220份豇豆地方品种进行21个重要性状的田间鉴定。结果表明,浙江省豇豆地方种质具有丰富的表型变异,基于表型数据的聚类分析可以将它们分为4个类群,其中类群Ⅲ的综合表现接近目前生产上的育成品种,具有较高的育种使用价值。本研究还利用豇豆物种特异的核心单核苷酸多态性(SNP)标记对其进行基因型鉴定,构建了各种质DNA指纹图谱,基于基因型数据将之分为4个亚群,其中亚群Ⅲ的荚长较长。本研究从多角度评价了浙江省豇豆地方种质的遗传多样性,研究结果可以为豇豆种质创新和新品种选育提供科学依据。

UV-C照射对鲜切豇豆的保鲜效果研究

为探究短波紫外线(UV-C)照射对鲜切豇豆的保鲜效果,在预试验结果的基础上,分别采用0、0.5 kJ/m^(2)的UV-C处理豇豆,然后将其置于4℃条件下贮藏,定期测定相关指标。结果表明:采用0.5 kJ/m^(2)UV-C照射可以维持鲜切豇豆较高的VC、可溶性固形物、可溶性蛋白和叶绿素含量,减少鲜切豇豆丙二醛(MDA)的积累,同时还能保持鲜切豇豆较高的总酚、类黄酮含量,并提高抗氧化酶的活性,包括过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX),一定程度上稳定多酚氧化酶(PPO)的活性。综合来说,0.5 kJ/m^(2)UV-C处理可用于鲜切豇豆的贮藏保鲜。

2022-2023年江苏省豇豆区域筛选试验(盐城点)

为筛选适宜江苏省种植的高产、优质的豇豆新品种,2022-2023年承担了江苏省豇豆区域试验。盐城点两年的试验结果表明,13个参试品种中,苏豇17-35总产量最高,比对照增产29.29%,其次是帮达夏龙,比对照增产27.80%,第3名是盐豇5号,比对照增产26.19%。对照苏豇3号产量最低,其他12个参试品种都比对照有不同幅度的增产,综合性状优良,建议继续进行生产试验,进一步鉴定品种的丰产性和稳定性。