Common Bean Crop Research Articles

Characterization of Maize, Common Bean, and Avocado Crops under Abiotic Stress Factors Using Spectral Signatures on the Visible to Near-Infrared Spectrum

Characterization of Maize, Common Bean, and Avocado Crops under Abiotic Stress Factors Using Spectral Signatures on the Visible to Near-Infrared Spectrum

Saccorhiza polyschides Extract as Biostimulant for Reducing Salt Stress Effect in Common Bean Crops

Salinity stress emerges as an important menace to global food security, particularly affecting susceptible crops such as common bean plants (Phaseolus vulgaris L.). The disruption of ion balances caused by salt stress within plant cells reduces water and nutrient absorption and hampers growth and productivity. Sacchorhiza polyschides, a brown macroalga rich in essential elements and macrominerals, has drawn attention as a natural biostimulant, being a potential remedy to bolster crop resilience against salt stress. This study delves into the effect of water extracts of Sacchorhiza polyschides (SPE) across varying concentrations (1%, 2%, and 5%) in common bean plants under salt stress (68.4 mM NaCl) conditions. Two different methods of application were used: by spraying the aerial part of the plant or by irrigation together with the watering solution. The effects of both systems of application were studied on the aerial parts of the plants. SPE exhibited significant enhancements in morphological parameters, chlorophyll content, carbon–nitrogen activities, and antioxidant enzymatic system activities, alongside increasing osmolyte accumulation, compared to salt-stressed plants without biostimulation. Moreover, SPE reduced reactive oxygen species (ROS) levels caused by salt stress, mitigating lipid peroxidation. The concentrations of 2% and 5% SPE applied by spraying showed the most significant results in most of the parameters analyzed. By shedding light on the underlying science behind this biostimulant effect, this research underscores the potential of SPE to enhance crop resilience and augment food production in salt-challenged environments.

Calibration and Evaluation of CERES-Maize and CROPGRO-Dry Bean Crop Simulation Models of the DSSAT in the Great Rift Valley Region of Ethiopia

Maize (Zea mays L.) is one of the most principal cereal crops ranking first in production in Ethiopia, predominantly produced and consumed directly by the smallholder farmers in the Great Rift Valley (GRV) of Ethiopia. Common bean (Phaseolus vulgaris) is also the most important legume crops as the source of protein and export commodity in the GRV. However, the average maize and common bean yields in Ethiopia are still low due to abiotic, biotic and socioeconomic constraints. In this regard, Crop simulation models (CSMs) are used in predicting growth and yield of crops and associated yield gaps under various management options and changing climatic parameters that are profitable with minimal unwanted impacts on the environment. Before using the CSMs, it is necessary to specify model parameters and understand the uncertainties associated with simulating variables that are needed for decision-making. Therefore, the research objective of this study was to calibrate and evaluate the performance of the CERES-Maize and CROPGRO-Dry bean CSMs of the Decision Support System for Agrotechnology Transfer (DSSAT) in the GRV of Ethiopia. The generalized likelihood uncertainty estimation (GLUE) method was used to estimate the genetic parameters of the CSM-CERES-Maize and CROPGRO-Dry bean models. Root mean squared error (RMSE) and Index of agreement (I) were used to evaluate the performance of the models. The DSSAT model reasonably reproduced observations for days to anthesis, days to physiological maturity, and grain yields, with values for the index of agreement of 0.97, 0.88 and 0.61 for CERES-Maize and 0.84, 0.75 and 0.51 for CROPGRO-Dry bean. Similarly, root mean square errors were moderate for days to anthesis (1.2 and 1.2 days), maturity (4.1 and 1.6 days), and yield (0.8 and 1.1 t/ha) for CERES-Maize and CROPGRO-Dry bean, respectively. The model has been successfully calibrated and evaluated for maize and common bean crop varieties and can now it can be taken for further applications in evaluating various crop and soil management options including climate smart agriculture technologies and climate change impact studies.

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.

Evaluation and Participatory Variety Selection of Common Bean (Phaseolus vulgaris L.) Varieties in Dawro Zone, South Western Region of Ethiopia

Farmers in the study area exhibit a unique tendency to choose varieties based on selection criteria rather than tested yields in the district. To ensure farmer participation, a study was conducted on six farmers’ farms, utilizing farmers as replicas in a Randomized Complete Block Design. Ten common bean crop varieties underwent evaluation on these farms to assess varieties in terms of farmer participation and identify priority criteria during the 2019 and 2020 production years. Plot sizes were standardized to 4m plot lengths with inter and intra-spacing of 40cm and 10cm, respectively. The seed and NPSB fertilizer rate were set at 100kg/ha and 122kg/ha, respectively. Significant differences were (P<0.05) were observed among treatments for plant height, days to 50% flowering, days to 90% maturity, and yield over two years. Notably, the common bean varieties Remeda, DAB 96, and SER 119 yielded 1641, 1601, and 1588.7kg/ha, respectively. Additionally, the farmers in the district preferred red-seeded varieties for production and consumption due to superior seed per pod, pod per plant, seed size, seed color, and seed yield. Moreover, these farmers preferred varieties established tolerance to major common bean diseases which were common in the district. Consequently, these high-yielding, farmers preferred, and disease-tolerant varieties are recommended for demonstration and large-scale production in the study regions and agro-ecological zones similar to those the trial was implemented in south western region of Ethiopia.

Multi-trait index: selection and recommendation of superior black bean genotypes as new improved varieties

Common bean provides diet rich in vitamins, fiber, minerals, and protein, which could contribute into food security of needy populations in many countries. Developing genotypes that associate favorable agronomic and grain quality traits in the common bean crop could increase the chances of adopting new cultivars black bean. In this context, the present study aimed at selection of superior black bean lines using multi-variate indexes, Smith-Hazel-index, and genotype by yield*trait biplot analysis. These trials were conducted in Campos dos Goytacazes - RJ, in 2020 and 2021. The experimental design used was randomized blocks, with 28 treatments and three replications. The experimental unit consisted of four rows 4.0 m long, spaced at 0.50 m apart, with a sowing density of 15 seeds per meter. The two central rows were used for the evaluations. The selection of superior genotypes was conducted using the multiple trait stability index (MTSI), multi-trait genotype-ideotype distance index (MGIDI), multi-trait index based on factor analysis and genotype-ideotype distance (FAI-BLUP), Smith-Hazel index, and Genotype by Yield*Trait Biplot (GYT). The multivariate indexes efficiently selected the best black bean genotypes, presenting desirable selection gains for most traits. The use of multivariate indexes and GYT enable the selection of early genotypes with higher grain yields. These lines G9, G13, G17, G23, and G27 were selected based on their performance for multiple traits closest to the ideotype and could be recommended as new varieties.

Features of the protection of phaseolus vulgaris crops from weeds

Goal. To determine the effect of herbicides on the weediness of crops and the yield of Phaseolus vulgaris seeds in the conditions of the Right Bank Forest Steppe of Ukraine. Methods. Informational and analytical (collection of materials and analysis of literary sources), field research (setting up experiments, observing the development of plants, determining biometric indicators, accounting for the number of weeds, collecting and determining the structure of the harvest), mathematical and statistical (processing of research results). The field experiment design included weeded and weed-protected plots to compare the development of common bean plants under different growing conditions. The results. It was established that the dominant weeds among cereals were chicken millet and gray mouse millet, and among dicotyledonous weeds - ragweed, white quinoa, common sedge, black solanum, field mustard, etc. The use of herbicide protection significantly improves the yield of Phaseolus vulgaris. The obtained yield increased on average by 1.93 - 2.01 t/ha compared to the weeded control. Conclusions. Weeding can significantly reduce the yield of common bean crops by competing for resources such as light, water and nutrients. Weed control helps conserve these resources for the Phaseolus vulgaris and increase its yield. The use of herbicides is an effective method of weed control, which promotes optimal growth of Phaseolus vulgaris. The increase in yield due to the application of herbicide protection can offset the costs of purchasing and applying the herbicide. It is important to consider the effectiveness of specific herbicides when choosing crop protection methods. Different herbicides can have different spectrums of action, that is, be effective against different types of weeds. The right choice will help optimize results and save costs. Therefore, weed control in common Phaseolus vulgaris crops through the application of herbicide protection is an important and effective strategy that can increase the yield and economic efficiency of common bean cultivation technology.

Alterations in Gene Expression during Incompatible Interaction between Amendoim Cavalo Common Bean and Colletotrichum lindemuthianum.

Anthracnose, caused by the fungus Colletotrichum lindemuthianum, poses a significant and widespread threat to the common bean crop. The use of plant genetic resistance has proven to be the most effective strategy for managing anthracnose disease. The Amendoim Cavalo (AC) Andean cultivar has resistance against multiple races of C. lindemuthianum, which is conferred by the Co-AC gene. Fine mapping of this resistance gene to common bean chromosome Pv01 enabled the identification of Phvul.001G244300, Phvul.001G244400, and Phvul.001G244500 candidate genes for further validation. In this study, the relative expression of Co-AC candidate genes was assessed, as well as other putative genes in the vicinity of this locus and known resistance genes, in the AC cultivar following inoculation with the race 73 of C. lindemuthianum. Gene expression analysis revealed significantly higher expression levels of Phvul.001G244500. Notably, Phvul.001G244500 encodes a putative Basic Helix-Loop-Helix transcription factor, suggesting its involvement in the regulation of defense responses. Furthermore, a significant modulation of the expression of defense-related genes PR1a, PR1b, and PR2 was observed in a time-course experiment. These findings contribute to the development of improved strategies for breeding anthracnose-resistant common bean cultivars, thereby mitigating the impact of this pathogen on crop yields and ensuring sustainable bean production.

Effects of alternative fertilization on common bean crops regarding productivity and nutritional levels

Considering the need for more information about productivity increases and nutritional improvement of soils, the present study evaluated the effects of alternative fertilization on grain yield and nutritional levels of bean crops. It was a randomized block study with four treatments and five replicates. The treatments were the absence of nitrogen fertilization, fertilizer use, chicken litter, and cattle manure. Organic fertilization provided lower variations in soil water availability during flowering and grain filling and increased nutrient concentrations, especially phosphorus and potassium. Chicken litter promoted the highest means for the number of legumes, the number of legumes on branches, the number of six-grain legumes, the mass of a thousand grains, grain mass per plant, and the normalized green-red difference index. However, the two organic fertilizers had significantly higher differences from chemical and no fertilization, showing that organic fertilizer applications must occur when nutrient availability coincides with the phenological stages essential for producing these fertilizers. High yields combined with favorable rainfall conditions occurred during crop development, as high soil moisture allowed faster mineralization of essential organic fertilizer nutrients, directly affecting yield. Pearson’s linear correlation allowed a better understanding of the participation of each plant trait in productivity, and the highest grain yield occurred with organic fertilization.

Geotechnologies in Biophysical Analysis through the Applicability of the UAV and Sentinel-2A/MSI in Irrigated Area of Common Beans: Accuracy and Spatial Dynamics

The applicability of remote sensing enables the prediction of nutritional value, phytosanitary conditions, and productivity of crops in a non-destructive manner, with greater efficiency than conventional techniques. By identifying problems early and providing specific management recommendations in bean cultivation, farmers can reduce crop losses, provide more accurate and adequate diagnoses, and increase the efficiency of agricultural resources. The aim was to analyze the efficiency of vegetation indices using remote sensing techniques from UAV multispectral images and Sentinel-2A/MSI to evaluate the spectral response of common bean (Phaseolus vulgaris L.) cultivation in different phenological stages (V4 = 32 DAS; R5 = 47 DAS; R6 = 60 DAS; R8 = 74 DAS; and R9 = 89 DAS, in 99 days after sowing—DAS) with the application of doses of magnesium (0, 250, 500, and 1000 g ha−1). The field characteristics analyzed were mainly chlorophyll content, productivity, and plant height in an experimental area by central pivot in the midwest region of Brazil. Data from UAV vegetation indices served as variables for the treatments implemented in the field and were statistically correlated with the crop’s biophysical parameters. The spectral response of the bean crop was also detected through spectral indices (NDVI, NDMI_GAO, and NDWI_GAO) from Sentinel-2A/MSI, with spectral resolutions of 10 and 20 m. The quantitative values of NDVI from UAV and Sentinel-2A/MSI were evaluated by multivariate statistical analysis, such as principal components (PC), and cophenetic correlation coefficient (CCC), in the different phenological stages. The NDVI and MCARI vegetation indices stood out for productivity prediction, with r = 0.82 and RMSE of 330 and 329 kg ha−1, respectively. The TGI had the best performance in terms of plant height (r = 0.73 and RMSE = 7.4 cm). The best index for detecting the relative chlorophyll SPAD content was MCARI (r = 0.81; R2 = 0.66 and RMSE = 10.14 SPAD), followed by NDVI (r = 0.81; R2 = 0.65 and RMSE = 10.19 SPAD). The phenological stage with the highest accuracy in estimating productive variables was R9 (Physiological maturation). GNDVI in stages R6 and R9 and VARI in stage R9 were significant at 5% for magnesium doses, with quadratic regression adjustments and a maximum point at 500 g ha−1. Vegetation indices based on multispectral bands of Sentinel-2A/MSI exhibited a spectral dynamic capable of aiding in the management of bean crops throughout their cycle. PCA (PC1 = 48.83% and PC2 = 39.25%) of the satellite multiple regression model from UAV vs. Sentinel-2A/MSI presented a good coefficient of determination (R2 = 0.667) and low RMSE = 0.12. UAV data for the NDVI showed that the Sentinel-2A/MSI samples were more homogeneous, while the UAV samples detected a more heterogeneous quantitative pattern, depending on the development of the crop and the application of doses of magnesium. Results shown denote the potential of using geotechnologies, especially the spectral response of vegetation indices in monitoring common bean crops. Although UAV and Sentinel-2A/MSI technologies are effective in evaluating standards of the common bean crop cycle, more studies are needed to better understand the relationship between field variables and spectral responses.

Identification of QTLs and validation of molecular markers associated with reaction to Fusarium wilt in the common bean cultivar BRS FP403

AbstractFusarium wilt, caused by the fungus Fusarium oxysporum f. sp. phaseoli, is one of the most prevalent diseases in the common bean crop (Phaseolus vulgaris). However, there is little information regarding the genetics of reaction to this disease. Thus, the aims of this study were to estimate genetic parameters, identify quantitative trait loci (QTLs) associated with reaction to Fusarium wilt, and validate the markers identified. A total of 165 progenies of the population BRS FP403 × BRS Horizonte were evaluated. Evaluation was made in 2016 and 2017 in field trials in an area infested with the pathogen in Santo Antônio de Goiás, Brazil. Genotyping of single nucleotide polymorphism and SilicoDArT, where DArT is Diversity Arrays Technology, markers using the DArTseq technology was performed in the F2 generation. Analyses of the phenotypic data indicated the presence of variability among the progenies and the possibility of success from selection, with high estimates of heritability (90%) and gain from selection (37%). A genetic map was obtained with 702 markers and spanned 3069 cM. Five QTLs associated with reaction to Fusarium wilt were identified on five chromosomes. There was interaction between the QTLs and years. Through joint analysis, four QTLs were identified on chromosomes Pv01, Pv02, Pv03, and Pv04, explaining 5.8%–40.5% of the variation. The QTL FOP2.3403H explained 40.5% of phenotypic variation and was stable over the 2 years. From this QTL, two hydrolysis probes were developed for genotyping in a panel of lines for validation. Selection efficiency was over 92%, indicating considerable potential for use in marker‐assisted selection.

Genome-wide analysis of PvMADS in common bean and functional characterization of PvMADS31 in Arabidopsis thaliana as a player in abiotic stress responses.

Changing climatic conditions with rising temperatures and altered precipitation patterns pose significant challenges to agricultural productivity, particularly for common bean crops. Transcription factors (TFs) are crucial regulators that can mitigate the impact of biotic and abiotic stresses on crop production. The MADS-box TFs family has been implicated in various plant physiological processes, including stress-responsive mechanisms. However, their role in common bean and their response to stressful conditions remain poorly understood. Here, we identified 35 MADS-box gene family members in common bean, with conserved MADS-box domains and other functional domains. Gene duplication events were observed, suggesting the significance of duplication in the evolutionary development of gene families. The analysis of promoter regions revealed diverse elements, including stress-responsive elements, indicating their potential involvement in stress responses. Notably, PvMADS31, a member of the PvMADS-box gene family, demonstrated rapid upregulation under various abiotic stress conditions, including NaCl, polyethylene glycol, drought, and abscisic acid (ABA) treatments. Transgenic plants overexpressing PvMADS31 displayed enhanced lateral root development, root elongation, and seed germination under stress conditions. Furthermore, PvMADS31 overexpression in Arabidopsis resulted in improved drought tolerance, likely attributed to the enhanced scavenging of ROS and increased proline accumulation. These findings suggest that PvMADS31 might play a crucial role in modulating seed germination, root development, and stress responses, potentially through its involvement in auxin and ABA signaling pathways. Overall, this study provides valuable insights into the potential roles of PvMADS-box genes in abiotic stress responses in common bean, offering prospects for crop improvement strategies to enhance resilience under changing environmental conditions.

Bean intercropping systems with small castor hybrids.

Research aimed at investigating the ideal plant arrangement system of common beans under intercropping with castor hybrids is necessary, as intercropping is a common practice in Brazil, and this practice affects the morphophysiological behavior of both crops. The objective of this study was to evaluate the consociation systems of common bean plants with small-sized castor hybrid, in three agricultural years, in the edaphoclimatic conditions of the Cerrado of Goiás, Brazil. In the three experiments, the randomized block design with four repetitions was used, involving the combination of five simultaneous sowing systems: beans sown on the castor row, on the inter-row, on the row + inter-row and beans and castor in monocropping. The bean cultivar used was Pérola; for castor the Agima hybrid was used. The plant height, primary yield components and the yield of the beans were evaluated, while for castor was evaluated the plant height, stem diameter, number of racemes per plant, plus the yield, in addition to the area equivalence index (AEI) to verify the efficiency of the intercropping. The arrangement of bean plants cv. Pérola on row and row + inter-row of the Agima 110204 castor hybrid provides higher yields of the legume. The yield of castor hybrids is not influenced by the common bean crop. The growing of common bean and the castor hybrid in the intercropping system is more efficient than the monocropping of both crops.

Structural analysis and molecular substrate recognition properties of Arabidopsis thaliana ornithine transcarbamylase, the molecular target of phaseolotoxin produced by Pseudomonas syringae.

Halo blight is a plant disease that leads to a significant decrease in the yield of common bean crops and kiwi fruits. The infection is caused by Pseudomonas syringae pathovars that produce phaseolotoxin, an antimetabolite which targets arginine metabolism, particularly by inhibition of ornithine transcarbamylase (OTC). OTC is responsible for production of citrulline from ornithine and carbamoyl phosphate. Here we present the first crystal structures of the plant OTC from Arabidopsis thaliana (AtOTC). Structural analysis of AtOTC complexed with ornithine and carbamoyl phosphate reveals that OTC undergoes a significant structural transition when ornithine enters the active site, from the opened to the closed state. In this study we discuss the mode of OTC inhibition by phaseolotoxin, which seems to be able to act only on the fully opened active site. Once the toxin is proteolytically cleaved, it mimics the reaction transition state analogue to fit inside the fully closed active site of OTC. Additionally, we indicate the differences around the gate loop region which rationally explain the resistance of some bacterial OTCs to phaseolotoxin.

Potential of Reinoculation Using R. tropici Applied under Cover to Increase Bean Yield

The common bean is known to require nitrogen, with mineral fertilizer being the main form of supply to the plants. However, more efficient inoculants containing strains of Rhizobium tropici that are potentially more efficient in fixing atmospheric N2 could replace the use of nitrogen fertilizers as long as some of the existing challenges in the application methodology are overcome (for example, ensuring the existence of active nodules in the most demanding crop phases: flowering and grain filling). This study aimed to verify the responses of common bean plants subjected to reinoculation using Rhizobium tropici in topdressing applied at different stages in a greenhouse and in a field between March and April 2020 and in the spring–summer harvest of 2020/2021, respectively. A randomized block design was used, along with four replications: T1 = uninoculated control; T2 = inoculation via seed (VS); T3 = VS + reinoculation at the V4 stage; T4 = VS + reinoculation at the R5 stage; T5 = VS + reinoculation at the R6 stage; T6 = VS + reinoculation at the V4 and R5 stages; T7 = VS + reinoculation at the V4 and R6 stages; T8 = VS + reinoculation at the R5 and R6 stages; T9 = VS + reinoculation at the V4, R5, and R6 stages; and T10 = mineral nitrogen fertilization. Nodulation and morphological variables were evaluated at the R7 stage, and agronomic variables were evaluated at the R9 stage at harvest. The use of reinoculation, in addition to inoculation, positively influenced the bean nodulation process. The morphological characteristics of the plants showed good development with the supply of N (carried out via inoculation and reinoculation), equivalent to the development that could be achieved via the addition of a mineral nitrogen fertilizer. Reinoculation from the R5 to R7 stages proved ineffective in supplying N to the common bean crop. Inoculation in the seed associated with reinoculation in coverage at the V4 stage provided higher yields (3.271 kg ha−1), reinforcing the potential for mineral nitrogen fertilizers to be replaced. The use of the seed inoculation technique with subsequent reinoculation under cover can completely replace the use of nitrogenous mineral fertilizers in fertilizing bean plants, making the cultivation of this fabacea more sustainable in terms of the associated costs and environmental problems.

Agronomic efficiency of rock phosphates used alone or associated with soluble source of phosphorus for corn and common bean crops cultivated in succession under no-tillage and irrigated system.

Agronomic efficiency of rock phosphates used alone or associated with soluble source of phosphorus for corn and common bean crops cultivated in succession under no-tillage and irrigated system.

Bacillus mexicanus sp. nov., a biological control bacterium isolated from the common bean (Phaseolus vulgaris L.) crop in Sinaloa, Mexico.

Strain FSQ1T was isolated from the rhizosphere of the common bean (Phaseolus vulgaris L.) crop sampled in a commercial field located in the Gabriel Leyva Solano community, which belongs to the Guasave municipality (state of Sinaloa, Mexico). Based on its full-length 16S rRNA gene sequence, strain FSQ1T was assigned to the genus Bacillus (100 % similarity). This taxonomic affiliation was supported by its morphological and metabolic traits. Strain FSQ1T was a Gram-stain-positive bacterium with the following characteristics: rod-shaped cells, strictly aerobic, spore forming, catalase positive, reduced nitrate to nitrite, hydrolysed starch and casein, grew in the presence of lysozyme and 2 % NaCl, utilized citrate, grew at pH 6.0-8.0, produced acid from glucose, was unable to produce indoles from tryptophan, and presented biological control against Sclerotinia sclerotiorum. The whole-genome phylogenetic results showed that strain FSQ1T formed an individual clade in comparison with highly related Bacillus species. In addition, the maximum values for average nucleotide identity and from Genome-to-Genome Distance Calculator analysis were 91.57 and 44.20 %, respectively, with Bacillus spizizenii TU-B-10T. Analysis of its fatty acid content showed the ability of strain FSQ1T to produce fatty acids that are not present in closely related Bacillus species, such as C18 : 0 and C20 : 0. Thus, these results provide strong evidence that strain FSQ1T represents a novel species of the genus Bacillus, for which the name Bacillus mexicanus sp. nov. is proposed. The type strain is FSQ1T (CM-CNRG TB51T=LBPCV FSQ1T).

ALLELOPATIC COMPATIBILITY OF COMMON BEAN AND COMPANION CROPS

Purpose. To investigate the allelopathic compatibility of common bean seeds and companion crops, to establish interaction patterns using water extracts from seeds and other plant parts of common bean and companion crops. Methods. Laboratory, statistical. Results. Biotest: interaction of germinating seeds of bean and companion crops in Petri dishes. Biologically active substances from winter and spring triticale seeds (the bean seeds/seeds of companion crops ratio was 1:10) negatively affected bean seedlings, which was seen from all parameters under investigation: hypocotyl length (with the root included), length of the longest adventitious root, the adventitious root number, and true leaf length (with epicotyl included). At a ratio of 1:5, winter triticale-induced inhibition of hypocotyl growth was enhanced up to 38 %, while, on the contrary, spring triticale had a neutral effect on this parameter. A stimulating effect (106 %) of spring triticale seeds on the true bean leaf length (with epicotyl) was noted. For winter and spring triticale in a ratio of 1:1 (compared to the control – without seeds of companion crops), inhibition of the growth of the hypocotyl with the root by 21 % and the true leaf with the epicotyl by 10–9 %, respectively, is observed. Biotest: germination of bean seeds in a water extract from whole seeds of bean and companion crops in Petri dishes. Water extract from spring triticale seeds in a ratio of 1:2 had the greatest stimulating effect on the tap root and the first leaf lengths; winter triticale extract in a ratio of 1:4 had the greatest effect on the adventitious root an epicotyl lengths; bean extract in a ratio of 1:2 had the greatest effect on the epicotyl length. Biotest: germination of bean seeds in a water extract from vegetative mass, roots and post-harvest residues of bean and companion crops in Petri dishes. Water extracts from roots of bean, winter and spring triticale weakly inhibited the main bean root elongation. A neutral allelopathic effect on the bean seed germination was exerted by extract from post-harvest residues of spring triticale. A water extract from top parts of bean had a negative allelopathic effect on germinating bean seeds, indicating self-incompatibility of this crop. Conclusions. The laboratory tests showed that biologically active substances from seeds of both winter triticale and spring triticale at a ratio of 1:10 were toxic for bean ssedlings. Combined germination of bean and spring triticale seeds at a ratio of 1:5 had a more positive effect compared to other ratios of seeds of companion crops, and combined germination of bean seeds with spring and winter triticale seeds at a ratio of 1:1 demonstrated very similar parameters of germinating bean seeds. It was found that water extracts from bean and spring triticale in a ratio of 1:2 and from bean and winter triticale (1:4) had a clear allelopathic effect on the bean parameters. Water extracts from winter triticale (1:1) and spring triticale (1:4) were more toxic to bean seedlings. Water extracts from roots of bean, winter and spring triticale weakly inhibited the main bean root elongation. A water extract from the aboveground parts of bean had a negative allelopathic effect on the germinating seeds of bean, indicating self-incompatibility of this crop. A neutral allelopathic effect on the germination of bean seeds was exerted by extract from post-harvest residues of spring triticale. Combined germination of seeds of bean and companion crops in the laboratory allows for assessments of peculiarities of seed germination and mutual influence of components as early as at the initial stage, for selection of crops for growing in heterogeneous fields aimed at forming a highly productive agrophytocenosis.

Boundary line analysis and machine learning models to identify critical soil values for major crops in Guatemala

AbstractAccurate and economically sound soil fertility recommendations are critical for ensuring profitable food production for smallholder farmers. However, such recommendations are lacking in many areas due to insufficient soil and crop response data. This study was conducted between 2016 and 2022 using boundary line analysis to evaluate crop response to soil fertility on 644 farms in Guatemala. We identify optimal soil property conditions for maize (Zea mays L.), common bean (Phaseolus vulgaris L.), and coffee (Coffea arabica L.) production in Guatemala and use crop price information to develop economically sound fertilization recommendations. We also analyzed the drivers of yield outcomes and assessed their relative importance with machine learning (ML) models. Results demonstrate that a majority of country‐level data currently have sub‐optimal soil nutrient levels and by optimizing nutrients, yields and profits could be improved in 64%, 51%, and 69% of maize, common bean, and coffee crops, respectively. In addition, ML underscored the central role of climate in shaping yield outcomes. Variable importance rankings from random forest indicated climate and water balance variables increased predictive accuracy more than soil parameters, highlighting the critical need for climate‐smart adaptations in the region. The pairing of boundary line with ML analysis provided unique and complementary information about factors that drive yield of major crops in Guatemala. This is an effective approach for developing fertility recommendations in Guatemala and could be replicated in other countries where critical nutrient recommendations are currently lacking for closing yield gaps and identifying yield response to climatic stochasticity.

Assessment of Root Rot Pathogens of Common Bean (Phaseolus Vulgaris L.) and Reaction of Genotypes to the Pathogens in West Hararghe Zone, Ethiopia

Common bean root rot caused by fungal pathogens is an important disease affecting common bean crops in Ethiopia. Information on pathogen identification, characterization, and management options is lacking for the Ethiopian bean production system. This study aimed to assess the major causal fungal pathogens and their management through host resistance methods. Initially, a field survey was conducted in three districts in 2016. It was cored forty-five (45) common bean fields. In the mean time, disease samples were collected for laboratory analyses. Secondly, pathogen identification and characterization were done in Laboratory at Haramaya University, followed by a pathogenicity test. Thirdly, a genotypic reaction was done on twenty common bean varieties by using four fungal genera (F. oxysporum, S. rolfsii, M. phaseolina, and R. solani) as experimental materials that were arranged in (CRD) design with three replications. Out of forty-five (45) common bean fields assessed 33 farms exhibited the disease. In the pathogenicity test, all the isolates were found pathogenic and showed a significant (p < 0.05) difference. In addition, the analysis of variance also showed that out of the tested twenty varieties, some released varieties (Dandesu, Tinike, SER-125, Dursitu, and Chorie), Chorie and (Dursitu, Chorie, Cranscope, Argene and SAB 632) showed highly significant at (p≤ 0.001) to Fusarium oxysporum f.sp. phaseoli, Sclerotium rolfsii, and Rhizoctonia solani while they didn’t exhibit any significant (p < 0.05) difference to Macrophomina phaseolina. In conclusion, those varieties showing resistance characters were recommended for growers.