Common Bean Production Research Articles

CRISPR/Cas9 editing of two adenine phosphoribosyl transferase coding genes reveals the functional specialization of adenine salvage proteins in common bean.

Adenine metabolism is important for common bean (Phaseolus vulgaris L) productivity since this legume uses ureides derived from the oxidation of purine nucleotides, as their primary nitrogen storage molecules. Purine nucleotides are produced from de novo synthesis or through salvage pathways. Adenine phosphoribosyl transferase (APRT) is the enzyme dedicated to adenine nucleobase salvage for nucleotide synthesis, but it also acts on the inactivation of cytokinin bases. In common bean, the APRT enzyme is encoded by four genes. Gene expression analysis, biochemical properties and subcellular location suggest functional differences among the common bean APRT isoforms. CRISPR/Cas9 targeted downregulation of two of the four PvAPRTs followed by metabolomics and physiological analyses of targeted hairy roots reveals that, although the two proteins have redundant functions, PvAPRT1 mostly participates in the salvage of adenine, whereas PvAPRT5 is the predominant form in the regulation of cytokinin homeostasis and stress responses with a high impact in root and nodule growth.

New emerging Pseudomonads as causal agents of bean blight disease

Common bean (Phaseolus vulgaris) production is negatively affected by several bacterial plant diseases. A severe outbreak of bean blight was observed in the nine major bean-producing provinces of Iran during 2021–2022. Necrotic spots were observed on leaves which become necrotic with chlorosis beyond it. One hundred-sixty bacterial strains with a greyish-white colony appearance were consistently isolated from the one-hundred eighteen symptomatic bean leaf, pod, seed and root samples on nutrient agar. All strains were screened for their ability to cause disease bean leaves among which 134 strains induced chlorosis three days after inoculation on bean leaves of cv. Yaghoot followed by necrotic spots on the inoculated sites one week after inoculation. The pathogenic strains clustered in three groups based on phenotypic characters and multilocus sequencing analyses. Three housekeeping genes including gyrB, rpoB, and rpoD of representative strains were partially sequenced. In the phylogenetic tree based on concatenated sequences of these three genes or each gene individually, the strains were divided into three clusters each with high bootstrap support. The first group of the strains clustered with Pseudomonas simiae CCUG 50988T. This is the first report of this species as causal agent of bean blight. The second group clustered close to Pseudomonas alloputida NMI5768T which apparently belong to a new species. The third group clustered in a separate clade in Pseudomonas chlororaphis species which belongs to a new subspecies based on pathogenicity on bean, phenotypic characters, sequences of five housekeeping genes which named as subsp. phaseoli subsp. nov. with the type strain UT-M315.

Effects of integrated fertilizer application on selected soil properties and yield attributes of common bean (Phaseolus vulgaris L.) on different soil types

In Ethiopia, common bean (Phaseolus vulgaris L.) productivity remains low because of low soil fertility. However, both plant production and soil fertility benefit from integrated application of fertilizers. Thus, this study investigates the effect of integrated application of inorganic, organic and biofertilizers on selected soil properties and yield components of common bean. A field experiment was conducted at three sites in southern Ethiopia, under two consecutive cropping season (2021 and 2022). The experiment was conducted using a randomized complete block design (RCBD) with three replications. The treatments included three levels of inorganic fertilizer (Triple Superphosphate, TSP), applied at 0, 42.5, and 85 kg TSP ha⁻1 for Kokate; 0, 29, and 58 kg TSP ha⁻1 for Hawassa; and 0, 35.5, and 71 kg TSP ha⁻1 for Alage, tailored to the specific conditions of each site. Additionally, the experiment incorporated three levels of organic inputs 0, 5 t biochar ha⁻1, and 5 t compost ha⁻1 as well as Rhizobium inoculation (HB-429) applied at 500 g ha⁻1. These treatments were designed to assess the combined effects of inorganic, organic and biofertilizers on soil health and crop performance. Results showed that the integrated application of inorganic, and organic fertilizers significantly (p ≤ 0.05) improved soil pH, soil organic carbon, and available P compared with the sole fertilizer application plots. Similarly, the integrated use of inorganic, organic and biofertilizers increased nodule numbers, seed weight, grain yield, and biomass yield. We also found that 23 and 24 % higher grain yield were achieved with integrated applications of TSP fertilizer with compost on Hawassa and Alage sites than sole inorganic fertilizer application. On the other hand, the integrated application of TSP fertilizer with biochar increased by 18 % grain yield on Kokate over the sole application of inorganic fertilizer. The highest economic benefit of 69,460 and 63,250 ETB was obtained from the integrated application of TSP fertilizer with compost at Hawassa and Alage sites, respectively. The highest economic benefit for the Kokate site was 53,583 ETB at TSP fertilizer with biochar application. Overall, the study confirms that site-specific integrated soil fertility management appears to be a prerequisite for sustainable and profitable common bean production over sole fertilizer application in southern Ethiopia.

The role of conservation agriculture in enhancing biodiversity and common beans productivity

Conservation of biodiversity in agricultural landscapes is vital for maintaining ecosystem stability and resilience. Conservation agriculture, a sustainable farming approach that involves minimum tillage and reduced use of synthetic pesticides, herbicides, and growth promoters, has gained attention as a potential strategy to enhance biodiversity and reduce production costs. This study investigated the role of conservation agriculture in enhancing biodiversity and common bean productivity in Tanzania. The study compared plots practicing conservation agriculture (minimum tillage and reduced agrochemical use) with those using conventional farming methods. Biodiversity metrics, that is, earthworm populations, bird species richness, bird nest abundance, bird species diversity, bee visitation rates, and bean yield were assessed. The results showed significant positive effects of conservation agriculture on biodiversity, emphasizing its potential role in promoting sustainable agriculture, biodiversity conservation, and household improvement due to reduced production costs and increased yield per unit area. Earthworms per meter square observed to increase from 12 in the non-conservation plots to 34 in the conservation plots, which is likely to improve nutrient cycling and productivity. Furthermore, conservation plots had a higher number of bird species flying around (36−76) compared with 14–32 in non-conservation plots (4000 m2) at 50 % bean flowering. The number of bird nests observed in the two plots during bean harvesting varied significantly (P<0.05), where the number of bird nests observed in 4000 m2 of non-conservation plots ranged from 14 to 36, compared to 12–62 in conservation plots. High bird nest numbers in conservation plots indicated higher bird habitat quality in conservation plots than in non-conservation plots. Bees as chief pollinators, bees visiting conservation plots during 50 % flowering per square meter ranged from 5 to 11, compared to 2–6 in non-conservation plots. Bee visitation to bean flowers has a significant influence on productivity, as it influences pollen transfer and fertilization. Common beans yield among plots ranged 0.9 tons/ha to 1.4 tons/ha in conservation plots compared to 0.35–1.01 tons/ha, in non-conservation plots. Land use conservation contributes considerably to economic growth through increased productivity and reduced production costs, where the production cost is reduced by 50 % in conservation plots compared with non-conservation plots. However, the present study was conducted in a single location with smallholder farmers; hence, further experiments over larger areas and longer time periods are needed for a more robust conclusion.

Investigating the influence of eco-friendly approaches on saline soil traits and growth of common bean plants (Phaseolus vulgaris L.).

Soil salinization significantly impacts agricultural lands and crop productivity in the study area. Moreover, freshwater scarcity poses a significant obstacle to soil reclamation and agricultural production. Therefore, eco-friendly strategies must be adopted for agro-ecosystem sustainability under these conditions. A study conducted in 2022 and 2023 examined the interaction effects of various soil mulching materials (unmulched, white plastic, rice straw, and sawdust) and chitosan foliar spray application (control, 250 mg L-1 of normal chitosan, 125 mg L-1 of nano chitosan, and 62.5 mg L-1 of nano chitosan) on the biochemical soil characteristics and productivity of common beans in clay-saline soil. Higher organic matter, available nutrient content, and total bacteria count in soils were found under organic mulching treatments (rice straw and sawdust). In contrast, the white plastic mulching treatment resulted in the lowest values of soil electrical conductivity (EC) and the highest soil water content. Conversely, chitosan foliar spray treatments had the least impact on the chemical properties of the soil. Plants sprayed with 62.5 mg L-1 of nano chitosan exhibited higher chlorophyll content, plant height, fresh weight of shoots and roots, seed yield, and nutrient content compared to other chitosan foliar spray applications. All treatments studied led to a significant reduction in fungal communities and Na% in plants. The combined effect of organic mulch materials and foliar spray application of 62.5 mg L-1 nano chitosan appeared to enhance biochemical saline soil properties and common bean productivity.

Comparative Effects of Water Scarcity on the Growth and Development of Two Common Bean (Phaseolus vulgaris L.) Genotypes with Different Geographic Origin (Mesoamerica/Andean).

Drought stress is widely recognized as a highly detrimental abiotic stress factor that significantly impacts crop growth, development, and agricultural productivity. In response to external stimuli, plants activate various mechanisms to enhance their resistance or tolerance to abiotic stress. The common bean, a most important legume according to the FAO, serves as a staple food for millions of people worldwide, due to its rich protein, carbohydrate, and fiber content, concurrently, and water scarcity is the main factor limiting common bean production. The process of domestication and on-farm conservation has facilitated the development of genotypes with varying degrees of drought stress resistance. Consequently, using landraces as biological material in research can lead to the identification of variants with superior resistance qualities to abiotic stress factors, which can be effectively integrated into breeding programs. The central scope of this research was to find out if different geographic origins of common bean genotypes can determine distinct responses at various levels. Hence, several analyses were carried out to investigate responses to water scarcity in three common bean genotypes, M-2087 (from the Mesoamerican gene pool), A-1988 (from the Andean gene pool) and Lechinta, known for its high drought stress resistance. Plants were subjected to different water regimes, followed by optical assessment of the anatomical structure of the hypocotyl and epicotyl in each group; furthermore, the morphological, physiological, and biochemical parameters and molecular data (quantification of the relative expression of the thirteen genes) were assessed. The three experimental variants displayed distinct responses when subjected to 12 days of water stress. In general, the Lechinta genotype demonstrated the highest adaptability and drought resistance. The M-2087 landrace, originating from the Mesoamerican geographic basin, showed a lower resistance to water stress, compared to the A-1988 landrace, from the Andean basin. The achieved results can be used to scale up future research about the drought resistance of plants, analyzing more common bean landraces with distinct geographic origins (Mesoamerican/Andean), which can then be used in breeding programs.

Factor analysis applied to simultaneous selection for resistance to anthracnose and angular leaf spot

AbstractDiseases such as anthracnose (Colletotrichum lindemuthianum) and angular leaf spot (Pseudocercospora griseola) can occur in common bean and compromise crop production, especially if susceptible cultivars are grown under conditions favorable to these diseases. The most efficient and sustainable alternative for controlling these diseases is the use of resistant cultivars. The identification of sources of resistance and the use of tools that assist in accurate selection of resistant cultivars are crucial to the success of breeding programs. The aim of this study was to characterize 67 carioca common bean cultivars recommended in Brazil regarding reaction to races 65, 73, 81, and 89 of C. lindemuthianum and to races 63‐23 and 63‐63 of P. griseola and to verify the application of factor analysis in the selection of cultivars resistant to both pathogens. The cultivars and resistant controls BRS Esplendor and MAIII.16‐159 were inoculated in a greenhouse in two experiments for each race. Cultivars were assessed for resistance to multiple races of anthracnose and angular leaf spot using artificial inoculation of plants at V2 stage. Factor analysis proved to be a good alternative for accurate selection of resistant cultivars. The percentage of cultivars simultaneously resistant to all races was low (8.95%). The cultivars Rudá R, VC 15, IAC‐Apuã, IAC‐Carioca Pyatã, BRSMG Amuleto, and BRS FC104 selected by factor analysis showed resistance to anthracnose and angular leaf spot. Therefore, these cultivars are potential sources of resistance for incorporation in bean breeding programs.

Advancing common bean (Phaseolus vulgaris L.) disease detection with YOLO driven deep learning to enhance agricultural AI

Common beans (CB), a vital source for high protein content, plays a crucial role in ensuring both nutrition and economic stability in diverse communities, particularly in Africa and Latin America. However, CB cultivation poses a significant threat to diseases that can drastically reduce yield and quality. Detecting these diseases solely based on visual symptoms is challenging, due to the variability across different pathogens and similar symptoms caused by distinct pathogens, further complicating the detection process. Traditional methods relying solely on farmers’ ability to detect diseases is inadequate, and while engaging expert pathologists and advanced laboratories is necessary, it can also be resource intensive. To address this challenge, we present a AI-driven system for rapid and cost-effective CB disease detection, leveraging state-of-the-art deep learning and object detection technologies. We utilized an extensive image dataset collected from disease hotspots in Africa and Colombia, focusing on five major diseases: Angular Leaf Spot (ALS), Common Bacterial Blight (CBB), Common Bean Mosaic Virus (CBMV), Bean Rust, and Anthracnose, covering both leaf and pod samples in real-field settings. However, pod images are only available for Angular Leaf Spot disease. The study employed data augmentation techniques and annotation at both whole and micro levels for comprehensive analysis. To train the model, we utilized three advanced YOLO architectures: YOLOv7, YOLOv8, and YOLO-NAS. Particularly for whole leaf annotations, the YOLO-NAS model achieves the highest mAP value of up to 97.9% and a recall of 98.8%, indicating superior detection accuracy. In contrast, for whole pod disease detection, YOLOv7 and YOLOv8 outperformed YOLO-NAS, with mAP values exceeding 95% and 93% recall. However, micro annotation consistently yields lower performance than whole annotation across all disease classes and plant parts, as examined by all YOLO models, highlighting an unexpected discrepancy in detection accuracy. Furthermore, we successfully deployed YOLO-NAS annotation models into an Android app, validating their effectiveness on unseen data from disease hotspots with high classification accuracy (90%). This accomplishment showcases the integration of deep learning into our production pipeline, a process known as DLOps. This innovative approach significantly reduces diagnosis time, enabling farmers to take prompt management interventions. The potential benefits extend beyond rapid diagnosis serving as an early warning system to enhance common bean productivity and quality.

Genes putatively involved in Phaseolus vulgaris resistance against Xanthomonas phaseoli pv. phaseoli revealed by a genome‐wide association study

AbstractCarioca and black bean groups play a significant role in Latin American common bean (Phaseolus vulgaris) consumption, serving as excellent sources of nutrients. One of the most significant threats for common bean production is common bacterial blight (CBB), a disease caused by the gram‐negative bacteria Xanthomonas phaseoli pv. phaseoli (Xpp) and Xanthomonas citri pv. fuscans (Xcf). An effective method for managing this disease is the use of plant genetic resistance. However, it is not known whether the same or overlapping sets of genes are associated with resistance to both pathogens. This study aimed to identify a repertoire of genes potentially associated with resistance to Xpp and compare it with that previously reported for Xcf. Eighty carioca and black common bean cultivars that had previously been challenged with Xcf were inoculated with a strain of Xpp, and a genome‐wide association study (GWAS) using single‐nucleotide polymorphisms (SNPs) and disease severity data was conducted. Three carioca and three black bean cultivars exhibited high levels of resistance to Xpp. Five SNPs with the highest −log10(p) values unveiled genes coding for diverse putative biochemical functions, including a light‐regulated Lir1 protein, a proton‐dependent oligopeptide transporter family protein, a metallo‐dependent phosphatase‐like protein, a WPP domain‐interacting tail‐anchored protein 2 and a pectin lyase‐like superfamily protein. No overlap between this repertoire of genes with that reported for Xcf was found. These findings provide important insights into genes potentially involved in the P. vulgaris resistance to Xpp and the complexity of the resistance response to CBB.

Global transcriptome analysis reveals resistance genes in the early response of common bean (Phaseolus vulgaris L.) to Colletotrichum lindemuthianum

BackgroundDisease can drastically impair common bean (Phaseolus vulgaris L.) production. Anthracnose, caused by the fungal pathogen Colletotrichum lindemuthianum (Sacc. and Magnus) Briosi and Cavara, is one of the diseases that are widespread and cause serious economic loss in common bean.ResultsTranscriptome analysis of the early response of common bean to anthracnose was performed using two resistant genotypes, Hongyundou and Honghuayundou, and one susceptible genotype, Jingdou. A total of 9,825 differentially expressed genes (DEGs) responding to pathogen infection and anthracnose resistance were identified by differential expression analysis. By using weighted gene coexpression network analysis (WGCNA), 2,051 DEGs were found to be associated with two resistance-related modules. Among them, 463 DEGs related to anthracnose resistance were considered resistance-related candidate genes. Nineteen candidate genes were coexpressed with three resistance genes, Phvul.001G243600, Phvul.001G243700 and Phvul.001G243800. To further identify resistance genes, 46 candidate genes were selected for experimental validation using salicylic acid (SA) and methyl jasmonate (MeJA). The results indicated that 38 candidate genes that responded to SA/MeJA treatment may be involved in anthracnose resistance in common bean.ConclusionsThis study identified 38 resistance-related candidate genes involved in the early response of common bean, and 19 resistance-related candidate genes were coexpressed with anthracnose resistance genes. This study identified putative resistance genes for further resistance genetic investigation and provides an important reference for anthracnose resistance breeding in common bean.

Pesticidal Plant Treatments Combined with Improved Soil Fertility Can Reduce Damage Caused by Fusarium Wilt (Fusarium oxysporum f.sp. phaseoli) and Bean Fly (Ophiomyia phaseoli) in Common Bean Production (Phaseolus vulgaris L.)

Pesticidal Plant Treatments Combined with Improved Soil Fertility Can Reduce Damage Caused by Fusarium Wilt (Fusarium oxysporum f.sp. phaseoli) and Bean Fly (Ophiomyia phaseoli) in Common Bean Production (Phaseolus vulgaris L.)

Determination of the Appropriate Blended Inorganic Fertilizer Rate Recommendation for the Optimal Common Bean (Phaseolus vulgaris L.) Grain Yield and Profitability in the Dawuro Zone, Ethiopia

Soil fertility decline is a significant factor affecting crop production. In a specific area, fertilizer application for a crop depends on soil type and profitability. Moreover, optimizing chemical fertilizer utilization in crop production is crucial from both environmental and economic perspectives. However, there is limited information available on the optimum NPSB fertilizer rate for common bean production in the study area. Thus, the study aimed to establish area-specific NPSB fertilizer rate recommendations for optimal grain yield and profitability of common bean. The field experiment was conducted in two locations in the 2019 and 2020 cropping seasons. The treatments included 0, 25, 50, 75, 100, 125, 150, 175, and 200 kg·ha−1 NPSB fertilizer rates, and they were planted using a randomized complete block design with three replications. The combined location analysis of variance indicated that the application of NPSB fertilizer significantly influenced plant height, number of pods per plant, number of seeds per pod, hundred-seed weight, biomass yield, grain yield, and harvest index. The highest grain yields (2815 kg·ha−1 and 3433 kg·ha−1) were recorded with the application of a 125 kg·ha−1 NPSB blended fertilizer rate, while the lowest grain yields (1429 kg·ha−1 and 1500 kg·ha−1) were produced from the nonfertilizer applied plot in Deneba and Wara, respectively. The combined location mean showed that the maximum grain yield (3124 kg·ha−1), followed by 2710 kg·ha−1, was produced by the application of 125 and 100 kg·ha−1 NPSB fertilizer rates, respectively. The data indicate that raising the NPSB fertilizer rate from 0 to 125 kg·ha−1 would greatly boost grain yield in the common bean in both locations in a similar manner. The economic analysis revealed that applying 125 kg·ha−1 of NPSB fertilizer earned the highest net benefits (140453.2 ETB·ha−1) with the highest marginal rate of return (1745.26%). Therefore, for high yield and profitability of common bean, a rate of 125 kg·ha−1 NPSB fertilizer is suggested in the study area and similar agro-ecological zones.

Trichoderma harzianum enhances root biomass production and promotes lateral root growth of soybean and common bean under drought stress

AbstractDrought stress (DS) is one of the main environmental stresses that determines crop productivity. It has been estimated that DS depresses over 40%–60% of soybean (Glycine max (L.) Merr.) and common bean (Phaseolus vulgaris L.) production worldwide, respectively. Although different agronomic strategies are sometimes implemented, the current goal in sustainable agriculture could involve the inoculation with native microorganisms to mitigate DS effects. A potential fungal candidate is Trichoderma, which is recognized as a ubiquitous soil inhabitant with growth‐promoting and biocontrol potentiality. However, its potential for mitigating the stress for water deficit is less well‐documented. Our objective was to evaluate the effect of inoculation with native Trichoderma harzianum strains on soybean and common bean growth under contrasting conditions of water availability. Seeds were independently inoculated (or not) with IB‐J15 and IB‐363 strains, and plants were submitted to DS or were kept under optimal irrigation (well‐watered, WW). In both legumes, the most evident effect after being inoculated was the modification of plant root architecture, the increase in root area and the development of lateral roots in plants under WW and DS conditions. In soybean, both Trichoderma strains had a positive inoculation response, both fresh and dry root biomass increased under WW, and remarkably under DS conditions. The main effect was an increase of about 110% in root dry weight under WW and, about 330% in DS in plants inoculated with IB‐J15 strain, meanwhile, plants inoculated with IB‐363 increased root dry weight 60% in WW and 177% in DS conditions. Notably in soybean, the inoculation with both Trichoderma strains increased the root area more than 70% in both WW and DS conditions. Common beans inoculated with IB‐363 under WW conditions, reached a positive inoculation responsiveness of around 247% in shoot dry weight biomass, and under WW both strains increased the root area more than 50%. Further, IB‐363 increased leaf area by 25% in WW and 72% in DS. Additionally, the in vitro co‐culture between both Trichoderma strains and nodulating Rhizobium etli and Bradyrhizobium japonicum E109 showed compatibility between microorganisms, since no inhibition of their growth was observed. We emphasize that plants inoculated with Trichoderma showed better resistance to water deficit, as seen by redistribution of photosynthates, prioritizing mainly, the development of the root system. © 2024 Association of Applied Biologists.

Botanical extracts control the fungal pathogen Colletotrichum boninense in smallholder production of common bean

Anthracnose caused by Colletotrichum spp. remains an intractable problem in the most common bean (Phaseolus vulgaris) production areas worldwide and can cause total yield loss. Many smallholder farmers are familiar with using botanical extracts to control insect pests; however, there is less familiarity with their use to control fungal diseases due to a lack of evidence. Here, we demonstrate that anthracnose could be controlled effectively by pesticidal plant species that are used for insect control. In laboratory trials, water extracts from 11 plant species could inhibit fungal growth (100%) and spore germination (75–100%) equally well to two commercially available fungicides, the synthetic Mancolaxyl and biofungicide Bioderma. In screenhouse trials, anthracnose disease was reduced by the extracts of three plant species. Moreover, bean crop growth in these botanical treatments did not differ significantly from that observed in the commercial fungicide treated plants. Field trials in a smallholder community reporting severe problems with anthracnose showed an effect similar to the screenhouse results. Field trials resulted in bean seed yields approximately 350 kg/ha higher in bean plants treated with Azadirachta indica and Lippia javanica at 10% w/v compared to the negative control untreated plants. In all trials, botanical extracts were as effective as commercially available fungicides, suggesting that these botanical extracts could provide dual-purpose pest and disease management for anthracnose and crop pest insects. The outcomes of this research show that prospects for using locally available resources to control anthracnose on common bean are credible and can be combined with controlling insect pests.

Genetic and pathogenic characterization of Rhizoctonia solani AG-4 isolates obtained from common bean

Common bean (Phaseolus vulgaris L.) is the most important grain legume. Crop production of common bean is affected by a number of diseases, such as Rhizoctonia root rot, being detected worldwide. Herein, we aimed to genetically and pathologically characterize Rhizoctonia solani isolates obtained from different provinces in Turkey. Anastomosis groups (AG) and subgroups of isolates were identified based on the sequence analysis of the rDNA-ITS region. The most prevalent subgroup was AG-4 HGIII, according to BLAST analysis and the phylogeny of resultant sequences, followed by AG-4 HGI and AG-4 HGII, respectively. iPBS retrotransposons highly supported the phylogenetic tree and provided a high level of genetic variability among isolates to discriminate AG subgroups. The results indicated that the iPBS DNA marker system based on retrotransposons could be used to discriminate Rhizoctonia isolates relying on AG grouping. The virulence of the pathogen isolates changed from 3.67 to 5 based on the agar-plate assay on the susceptible cv. Gina. The reactions of thirty common bean cultivars were also evaluated against the most aggressive isolate in each subgroup. The reaction assay showed significant differences among both isolates and cultivars; the highest disease severity among cultivars was observed to AG-4 HGI, followed by AG-4 HGIII and AG-4 HGII, respectively. None of the cultivars showed resistance to all AG subgroups. Screening of AGs among the isolates and selecting cultivars are critical to managing Rhizoctonia disease due to the range of host suitability according to AG subgroups.

Screening of Common Bean Genotypes for Their Resistance to Bean Stem Maggot (Ophiomyia Spp.) in Ethiopia

Common bean production in Africa faces various constraints, including biotic and abiotic stress. Among biotic stresses, bean stem maggots (BSM) (Ophiomyia spp.) are the most damaging insect pests of common beans in central and sub-Saharan Africa, especially under poor soils and dry conditions. Various control measures are available for bean stem maggots; however, there is insufficient information regarding the resistance of common bean genotypes to this pest. The present study aimed to identify sources of resistance to BSM in two groups of genotypes, namely red mottled and sugar bean, at Negelle Arsi and Shalla in Ethiopia during 2016 and 2017. A total of 111 genotypes with 56 belonging to the red mottled group and 55 to the sugar bean group were assessed for their resistance levels in open fields with a history of BSM infestation following randomized complete block design with three replications. In the 2016 assessment, 23 genotypes exhibited significantly lower numbers of dead seedlings and damage scores in both bean groups and locations. The results for the second year (2017) indicated that four genotypes from the red mottled group (DAB-365, DAB-398, DAB-449, and DAB-331) and four from sugar beans (DAB-500, DAB-512, DAB-483, and DAB-54) were moderately resistant to BSM in both locations. The combined findings from the 2016 and 2017 cropping seasons revealed that DAB-500, DAB-512, DAB-483, and DAB-541 from the red mottled group, and DAB-365, DAB-398, DAB-449, and DAB-331 from the sugar bean group, exhibited resistance to BSM at both locations. Therefore, based on the aforementioned information, these eight genotypes from both groups are recommended as potential sources of resistance to bean stem maggots for further common bean breeding purposes.

Additive intercropping system or acaricides: which one is more efficient to prevent population buildup of two-spotted spider mite?

Habitat manipulation such as intercropping can be used as a simple and common cultural practice in pest management. This method is based on the principle of reducing pest populations by increasing the diversity of an ecosystem. This study has been carried out to evaluate the influence of additive series intercropping common bean with some aromatic plants (AP), and 2 acaricides on the different life stages (egg, immature mobile stages, and adult) of Tetranychus urticae Koch (Trombidiformes: Tetranychidae), over 2 yr of experimentation (2020 and 2021). This experiment was conducted following a randomized complete block design with 7 treatments including common bean monoculture, common bean sprayed by spiromesifen or Dayabon, and common bean + companion plants (coriander, ajwain, basil, or dill). Each treatment was replicated 3 replicates. The lowest and highest number of eggs, immature mobile stages, and adults were observed in common bean + spiromesifen and the common bean monoculture, respectively. Additionally, the common bean + Dayabon supported significantly different T. urticae life stage densities compared to common bean monoculture. Also, among intercropped treatments, common bean + basil showed the lowest number of T. urticae (eggs, immature mobile stages, and adults). The highest yield and land equivalent ratio were recorded in common bean + basil and common bean + spiromesifen, respectively. Finally, it can be concluded that additive intercropping with these AP can effectively decrease the T. urticae population density, which is useful for the safe production of common bean.

Productivity and basic indicators of common bean (haricot) modern varieties suitability for mechanized harvesting

Goal. Investigation of plants height, a lower bean attachment height, 1000 seeds weight, ripening period duration, and productivity of common bean (haricot) modern varieties, depending on cultivating technological methods.&#x0D; Methods. Field method — to determine the plants height and grain crop capacity; laboratory one — to determine the basic elements of common bean plant crop structure; statistical — for mathematical data processing by variance analysis method.&#x0D; Results. All the six common (haricot) bean varieties investigated in the research, were bushy. However, the varieties Nata and Bukovynka showed the «chick-pea» (twisted) top appearance in years with excessive humidity. The variety Slavia was characterized by the lowest height of the lower bean attachment — 8.1—8.8 cm. Other researched varieties were more technologic. Particularly, the variety Galaktyka had the lower bean attachment height 10.1—10.6 cm, Bukovynka — 10.5—11.5, Nata — 10.5—11.8, Ros’ — 11.4—12.4 cm. The lower bean elevated location of the variety Otrada (12.9—13.5 cm) allows to minimize the losses during direct combine harvesting. All the varieties investigated by us had a medium-sized seed (from 201 tо 400 g). The smallest seed was in the variety Bukovynka — 204—212.6 g. The largest 1000 seeds weight was in the variety Galaktyka — 323.5—337.9 g. All the common bean vaieties researched in the experiment, except Galaktyka, exceeded the variety Bukovynka by grain yield. Thus, on the variant without seed inoculation and using potassium humate, the variety Galaktyka grain yield made 1.33 t/hа, which was by 34.5% less, compared to the variety Bukovynka. A complex use of inoculants and potassium humate provided a significant grain yield increase of the researched common bean varieties. The maximum yield increase in the research (0.27 t/hа or 11.0%) was obtained during pre-sowing seed inoculation and two foliar feedings with potassium humate of common bean stands of the variety Otrada.&#x0D; Conclusions. All the varieties researched in the experiment are bushy, and bushy with a «chick-pea» (twisted) top and suitable for direct combine harvesting. The maximum grain yield level was provided by the following varieties: Otrada — 2.72 t/ hа; Nata — 2.65 t/hа, and Ros’ — 2.54 t/hа, during seed inoculation with biologics Rhizoactive + Rootella, complete mineral fertilizer introduction in dosage N32Р32К32, and two foliar feedings with potassium humate.

Influence of different fertilization programs on dry seeds production of common bean

Influence of different fertilization programs on dry seeds production of common bean

Nitrogen management in common bean cultivars in soil infected by Meloidogyne incognita

The selection of an appropriate nitrogen (N) source can mitigate the negative effect of root-knot nematodes on the yield of common beans. A greenhouse experiment was conducted to assess the application efficiency of four N sources (urea, ammonium sulfate, ammonium nitrate, and sodium nitrate) and inoculation with Rhizobium tropici on the yield components, chlorophyll, and total nitrogen (N) leaf contents of four common bean cultivars (IDR Curió, IDR Sabiá, IDR Tuiuiú, and IDR Bem-te-vi). These beans were cultivated in substrates both infected and uninfected with Meloidogyne incognita. In the soil containing phytonematodes, the IDR Curió cultivar exhibited the highest shoot and root dry weight yield, resulting in the greatest root volume, total N content, and grain yield. Among the N sources, the application of either urea or ammonium sulfate proved the most effective in enhancing common bean productivity in soil, irrespective of the cultivar or whether the soil was infected with Meloidogyne incognita.