Search Results (82)

The yield of common bean (Phaseolus vulgaris L.) is limited by abiotic stresses such as drought and high temperatures, which frequently occur simultaneously under field conditions. This study examined 100 bean genotypes under three environmental conditions, namely, the rainy season (optimal conditions), full irrigation in the dry season (high-temperature stress), and terminal drought in the dry season (combined stress), via a 10 × 10 triple-lattice design. Agronomic parameters evaluated included days to flowering (DF), days to physiological maturity (DM), plant height (PH), aerial biomass (BIO), grain yield (YLD), and 100-seed weight (100SW). The natural temperature exceeded 35 °C during the reproductive stage of the dry season. Combined stress revealed differential adaptive mechanisms in the tested germplasms, indicating that the response to multiple stresses is more complex than the sum of individual stress responses. The average yield under optimal conditions was 1344 kg/ha, decreasing to 889 kg/ha (66.1%) under irrigation with high temperatures and to 317 kg/ha (23.6%) under terminal drought with high temperatures. Under terminal drought with high temperatures, the number of days to maturity decreased by 5%, and the seed weight decreased by 20%. The G69-33-PT and G-19158 genotypes presented high yields under high-temperature stress, with yields above 1800 kg/ha, suggesting specific physiological mechanisms for tolerance to elevated temperatures. Under combined stress, genotypes G69-Sel25, Pinto Mestizo, and Dalia presented yields above 680 kg/ha, indicating adaptations in terms of water use efficiency and tolerance to high temperature. The identification of genotypes with differential stress tolerance provides valuable genetic resources for breeding programs. The diverse origins of superior germplasms (bred lines, landraces, and commercial cultivars) highlight the importance of exploring various germplasms in the search for sources of abiotic stress tolerance for breeding projects aimed at developing cultivars adapted to climate change scenarios where drought and high temperatures occur simultaneously. Full article

The common bean is a widely cultivated food source. Many domesticated species of common bean varieties, known as landraces, are cultivated in Mexico by local farmers, exhibiting various colorations and seed mixtures as part of agricultural practices. In this work, we propose a methodology for classifying bean landrace samples using three two-dimensional histograms with data in the CIE L*a*b* color space while additionally integrating chroma (C*) and hue (h°) to develop a new proposal from histograms, employing deep learning for the classification task. The results indicate that utilizing three histograms based on L*, C*, and h° brings an average accuracy of 85.74 ± 2.37 compared to three histograms using L*, a*, and b*, which reported an average accuracy of 82.22 ± 2.84. In conclusion, the new color characterization approach presents a viable solution for classifying common bean landraces of both homogeneous and heterogeneous colors. Full article

The classification of bean landraces based on their coloration is of particular interest, as the color of these plants is associated with the nutritional components present in their seeds. In this paper, the authors propose a procedure to identify the colors of heterogeneous color bean landraces based on the information from their digital images. The proposed methodology employs a three-dimensional histogram representation of the estimated color, expressed in the CIE L*a*b* color space, with an unsupervised learning method called the Gaussian Mixture Model. This approach facilitates the acquisition of representative information for the colors of a bean landrace, represented as points in the CIE L*a*b* color space. Furthermore, the K-$nn$ method can be trained with these punctual representations to identify colors, yielding satisfactory results on landraces with homogeneous and heterogeneous seeds. Full article

Common beans (Phaseolus vulgaris L.) are considered a socially and economically important crop, with the biggest growers in India, Myanmar, and Brazil. Traditionally, common beans are also grown in most parts of Europe, including Latvia, where cultivation areas have remained relatively constant since the middle of the last century. This is explained by the plant’s higher thermal requirements compared to peas and faba beans more widely grown here. Despite this, landraces adapted to local conditions have been developed, whose origin and potential relationship with another European common bean germplasm is very limited. Therefore, the study aimed to characterise the morphology of the common bean germplasm collected and grown in Latvia to identify the most valuable material for further crop development and evaluate the local landraces in the European common bean germplasm context. The 28 genotypes representing Latvian landraces and European reference genotypes were phenotyped using 26 traits of bean seeds, pods, leaves, flowers, and stems, which were evaluated according to an internationally applied methodology. Latvian varieties showed phenotypical variability and characteristics that were different from those found in other European regions, showing the significance of the germplasm under study and highlighting the need for conservation. Local varieties (landraces) are reservoirs of unique genetic traits. Their adaptability to local environmental conditions, resistance to pests and diseases, and their potential to enhance nutritional quality make them invaluable resources for in situ conservation efforts and targeted genetic improvement programmes. Emphasising the utilisation of these landraces can contribute to sustainable agriculture, climate resilience, and food security. Full article

The common bean (Phaseolus vulgaris L.) arrived in Europe in the sixteenth century from the American continent and spread across the old continent as a result of adaptation to different climatic and geographical conditions, as well as selection for different cultivation techniques and eating habits. This expansion gave rise to a huge number of landraces, which have now been largely replaced by more productive cultivars. To avoid losing this genetic diversity heritage, it is essential to characterize the genetic resources at risk of extinction for correct in situ/ex situ conservation and as a first step toward promoting and relaunching their exploitation. In this article, we report the study of a group of Borlotti beans, both landraces and modern cultivars, which are typically cultivated in Northern Italy. The aim was to explore the variability within the assembled Borlotti panel to assess whether landraces have maintained their morphological and genetic identity over time during on-farm cultivation. In particular, we investigated whether it is possible to distinguish between landraces and commercial accessions, a topic that has so far been understudied, but in the field of conservation, it is particularly important because it allows for the prioritization of preserving genetic resources. We found distinctive traits among the various accessions, with only a few landraces maintaining their identity, many of which should more properly be defined as obsolete cultivars. Taken together, these data indicate that it is possible to establish a priority scale for in/ex situ conservation by comparing landraces and cultivars using morphological and genetic data. Furthermore, thanks to geographical isolation, on-farm conservation has proven to still be successful in maintaining the identity of landraces. Full article

Biofortification has emerged as an important approach for improving minerals and vitamin deficiencies through the application of agronomic and biotechnological methodologies. Vitamin A, one of the most deficient vitamins, disproportionately affects children in developing countries, highlighting the urgent need for vitamin A-enriched cultivars. The present study aimed to characterize common bean germplasm for vitamin A contents and to identify the genomic regions associated with this trait. A total of 177 common bean landraces and 6 commercial cultivars were evaluated under five environments and two locations. Analysis of variance revealed highly significant environmental effects and genotype × environment interactions. Across all years and all locations, Bilecik-6 exhibited the lowest vitamin A contents (1.67 µg/100 g dry seed), while Civril-Bolu had the highest (3.23 µg/100 g dry seed). Landraces from Balıkesir province were found to be rich in vitamin A content and should be considered as potential genetic resources for common bean biofortification. Additionally, a genomic region located on Pv06 was identified as being linked to vitamin A content. The genomic and genetic resources identified in this study will be valuable for the breeding community aiming to develop vitamin A-enriched common bean cultivars. Full article

Rhizoctonia root rot and web blight caused by Rhizoctonia solani Kühn is one of the destructive diseases of the common bean (Phaseolus vulgaris L.). A two-year study was conducted (2019–2021) to evaluate the common bean landraces and genotype, biocontrol agents, and chemical fungicides against the pathogen. Nine landraces from high-altitude agriculture in the Jumla district in western Nepal (29.27443900, 82.19332200; 2540 m msl) and one genotype of commercial common bean from the sub-tropical Chitwan district in central Nepal (27.65186564, 84.34869288; 256 m masl) were evaluated for resistance against the pathogen under screenhouse and field conditions. All were found highly susceptible to the pathogen and the highest lesion length (3.02 cm) was measured in the Rato Male Simi followed by Rato Sano Chhirke Simi (2.40 cm) in Chitwan conditions. Three chemical fungicides—SAAF™ (carbendazim 12% + mancozeb 63% WP), Vitavax^® (carboxin 37.5% + thiram 37.5% DS), and Nativo^® (tebuconazole 50% + trifloxystrobin 25% w/w (75 WG)—and three biocontrol agents—Trichoderma viride (10⁹ cfu/mL), Pseudomonas fluorescens (10⁹ cfu/mL), and Bacillus subtilis (10⁸ cfu/mL)—were evaluated as seed and soil treatments in fourteen different combinations against R. solani. SAAF™ and Vitavax^® were found highly effective as they completely suppressed the incidence of pre-emergence damping off. SAAF™ was equally effective followed by Vitavax^® and Nativo^® in suppressing post-emergence damping off. On the other hand, the highest disease incidence (26.63%) was recorded in treatment where seed treatment with Pseudomonas fluorescens formulation at the rate of 10 g per kg of FYM slurry along with soil application with Pseudomonas fluorescens formulation at the rate of 10 kg per ha with 50 kg FYM was applied, whereas the lowest disease incidence (4.96%) occurred in SAAF™ for both seed and soil applications. Highest grain yield (4125 kg/ha) was recorded on Nativo^® where seed treatment at the rate of 1.5 g per kg along with soil drenching at the rate of 1.5 g per liter was used. Thus, it can be concluded that the best control for pre-emergence damping off was achieved by SAAF™ where seed treatment at the rate of 2 g per kg along with soil drenching at the rate of 2 g per liter and Vitavax^® as seed treatment at the rate of 2 g per kg along with soil drenching at the rate of 2 g per liter was used, while the best control of post-emergence damping off was achieved with combined seed treatment and soil treatment with SAAF™. There was no incidence of web blight throughout the growing period. Our findings could be useful in devising strategies for the integrated management of R. solani causing root rot disease in common beans. Full article

The cacao plant, Theobroma cacao, is economically significant, as its beans are essential for chocolate production. Cacao from Tumaco on Colombia’s Pacific coast is renowned for its distinct flavor and aroma, accessing specialty markets. However, production challenges include low yields, inconsistent post-harvest practices, and limited knowledge of local genotypes. To tackle these issues, a research project genetically characterized 25 Tumaco landraces, establishing their phylogenetic relationships using reduced representation libraries (RRL). The analysis yielded 359,950 single nucleotide polymorphisms (SNPs) for Tumaco and identified 38,812 SNPs in common with Colombian National Germplasm Bank genotypes and reference groups. Genetic structure analysis divided Tumaco samples into nine populations, revealing admixtures primarily from the Nacional, Iquitos, Amelonado, and Criollo groups. Some Tumaco samples showed predominant ancestry from the Iquitos group, while others leaned towards the Nacional type, with limited Criollo and Contamana ancestry. No Tumaco landrace exhibited complete ancestry from a single group, suggesting a hybrid origin. These insights into Tumaco’s genetic diversity and structure are essential for improving landraces in Colombia’s Pacific region, contributing to the genetic enhancement of cacao. Full article

This study aimed to characterize the genetic diversity and morphological traits of 32 populations of Phaseolus coccineus collected from the Aniene Valley. Quantitative seed trait analyses revealed that Mandolone accessions exhibited significantly higher seed weights and dimensions compared to Fagiolone accessions. Specifically, Mandolone accessions showed an average weight of 189.48 g per 100 seeds, with seed heights and lengths averaging 14.38 mm and 23.84 mm, respectively. In contrast, Fagiolone accessions had an average seed weight of 174.13 g, with seed heights and lengths of 13.95 mm and 22.58 mm, respectively. Molecular analysis, conducted using 9 polymorphic SSR loci, identified 53 alleles across 320 genotypes, with a mean expected heterozygosity (He) of 0.695. This indicated that there was high genetic variability within the Aniene Valley populations. The genetic diversity analysis revealed two genetic clusters corresponding to the Mandolone and Fagiolone landraces. This was supported by UPGMA, PCoA, and STRUCTURE analyses. This study highlights the need to conserve the genetic diversity within these landraces and provides a basis for the development of conservation strategies for P. coccineus germplasms in the singular ecological context of the Aniene Valley. Full article

In the present work, a subset extracted from a core collection of common beans (Phaseolus vulgaris L.) landrace accessions from the Lazio region in central Italy was used to identify the most suitable drought-tolerant or -susceptible genotypes. By applying several morpho-physiological and agronomic selection criteria recommended by the available literature, we conducted a pre-screening experiment under controlled conditions on a primary group of 24 landraces. These landraces were chosen to represent the diversity in the Lazio region in terms of geographical provenance, elevation, landform, growth habit, customary water management in the field, and native gene pool. Pre-screening under controlled conditions allowed us to identify two subsets of landraces: one exhibiting the most drought-tolerance and one showing the most susceptibility to drought. These two subsets were then tested in field trials using two water treatments, i.e., normal irrigation versus no irrigation. Such field experiments were simultaneously conducted at two sites within the Lazio region, deliberately chosen to maximize their differences in terms of pedo-climatic conditions. This notwithstanding, the core findings from the two separate field experiments were remarkably consistent and coherent among each other, highlighting a notable degree of variability within the group of the tested landraces. In general, the morpho-physiological traits considered were found to be less responsive to water shortage than yield parameters. A statistically significant Landrace × Treatment interaction was found for almost all the yield parameters considered, suggesting that certain genotypes are more susceptible than others to water shortage. By taking into account the concept of “yield stability”, i.e., the ability to maintain comparatively high yields even under conditions of water scarcity, certain common bean landraces were found to be the most promising, in terms of drought tolerance. Two genotype pairs, in particular, could be of interest for studying the morpho-physiological and molecular mechanisms underlying drought tolerance in common bean, as well as for identifying quantitative trait loci associated with water scarcity, which could be beneficially employed in breeding programs. The results reported here also suggest that pre-screening under laboratory conditions, followed by targeted field trials, can constitute a reliable, efficient, and resourceful combined approach, in which morpho-physiological traits measured on juvenile plants might play a role in predicting drought tolerance at the agronomic level. Full article

This study aimed to characterize forty genotypes (31 landrace varieties and nine commercial cultivars) of common bean (Phaseolus vulgaris L.) morphologically and molecularly. Morphological descriptors were evaluated during seedling, flowering, physiological maturation and post-harvest stages. Ten microsatellite markers were used for molecular screening. The markers were analyzed according to the number of alleles per locus, the allele frequency per locus and the polymorphism in content (PIC). Genetic distances and cluster analysis were performed using Bayesian inference and the UPGMA method. All black beans evaluated have anthocyanin in the cotyledons, hypocotyls and stems, and their flowers are purple. For the growth habit, 50% of the evaluated genotypes belong to type III, and at the physiological maturation stage, yellow color is predominant in the pods (85%). Through the genetic dissimilarity, three groups were observed for the likelihood reason, and five groups were observed through the UPGMA method, a strong indication of the wide genetic diversity among the evaluated genotypes. All genotypes from the Andean center of origin were grouped into the same cluster. Full article

The objective of this study was to evaluate the genetic diversity among traditional common bean accessions through morphological descriptors and molecular markers. Sixty-seven common bean accessions from the Germplasm bank of the Instituto Federal of Espírito Santo—Campus de Alegre were evaluated. For this, 25 specific morphological descriptors were used, namely 12 quantitative and 13 qualitative ones. A diversity analysis based on morphological descriptors was carried out using the Gower algorithm. For molecular characterization, 23 ISSR primers were used to estimate dissimilarity using the Jaccard Index. Based on the dendrograms obtained by the UPGMA method, for morphological and molecular characterization, high genetic variability was observed between the common bean genotypes studied, evidenced by cophenetic correlation values in the order of 0.99, indicating an accurate representation of the dissimilarity matrix by the UPGMA clustering. In the morphological characterization, high phenotypic diversity was observed between the accessions, with grains of different shapes, colors, and sizes, and the accessions were grouped into nine distinct groups. Molecular characterization was efficient in separating the genotypes in the Andean and Mesoamerican groups, with the 23 ISSR primers studied generating an average of 6.35 polymorphic bands. The work identified divergent accessions that can serve different market niches, which can be indicated as parents to form breeding programs in order to obtain progenies with high genetic variability. Full article

Phaseolus lunatus L. is a species of landrace bean widely cultivated in Northeast Brazil. The integration of new technologies in the agricultural sector has highlighted the significance of seed images analysis as a valuable asset in the characterization process. The objective was to assess the morphology of 18 P. lunatus varieties gathered from four states in the Brazilian Northeast. To achieve this, 100 seeds from each variety were utilized, and their images were acquired using a flatbed scanner with a digital resolution of 400 dpi. Subsequently, the images were processed using the ImageJ software package for analyzing seed size, shape and color characteristics. Statistical analyses were performed with SPSS software applying stepwise Linear Discriminant Analysis (LDA). The overall accuracy rate for correct identification was 80.5%. Among the varieties, the lowest classification percentage was attributed to the ‘Coquinho Vermelha’ variety (39%), while the highest rates were observed for ‘Fava Roxa’ and ‘Fava de Moita’ (98%). The morpho-colorimetric classification system successfully discriminated the varieties of P. lunatus produced in the northeastern region of Brazil, highlighting the -+*/high degree of diversity within them. In particular, seeds with uniform coloring or clearly defined secondary color patterns were easier to classify. The varieties showed low correlation, forming distinct groups based on background color, secondary color, or seed size. Full article

The concentration of anthocyanins in common beans indicates their nutritional value. Understanding this concentration makes it possible to identify the functional compounds present. Previous studies have presented color characterization as two-dimensional histograms, based on the probability mass function. In this work, we proposed a new type of color characterization represented by three two-dimensional histograms that consider chromaticity and luminosity channels in order to verify the robustness of the information. Using a neuroevolutionary approach, we also found a convolutional neural network (CNN) for the regression task. The results demonstrate that using three two-dimensional histograms increases the accuracy compared to the color characterization represented by one two-dimensional histogram. As a result, the precision was 93.00 ± 5.26 for the HSI color space and 94.30 ± 8.61 for CIE L*a*b*. Our procedure is suitable for estimating anthocyanins in homogeneous and heterogeneous colored bean landraces. Full article

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. Full article