Common Bean Accessions Research Articles

A single-nucleotide polymorphism in PvPW1 encoding β-1,3-glucanase 9 is associated with pod width in Phaseolus vulgaris L.

Pod width influences pod size, shape, yield, and consumer preference in snap beans (Phaseolus vulgaris L.). In this study, we map PvPW1, a quantitative trait locus associated with pod width in snap beans, through genotyping and phenotyping of recombinant plants. We identify Phvul.006G072800, encoding the β-1,3-glucanase 9 protein, as the causal gene for PvPW1. The PvPW1G3555 allele is found to positively regulate pod width, as revealed by an association analysis between pod width phenotype and the PvPW1G3555C genotype across 17 bi-parental F2 populations. 97.7% of the 133 wide pod accessions carry PvPW1G3555, while 82.1% of the 78 narrow pod accessions carry PvPW1C3555, indicating strong selection pressure on PvPW1 during common bean breeding. Re-sequencing data from 59 common bean cultivars identify an 8-bp deletion in the intron linked to PvPW1C3555, leading to the development of the InDel marker of PvM436. Genotyping 317 common bean accessions with PvM436 demonstrated that accessions with PvM436247 and PvM436227 alleles have wider pods compared to those with PvM436219 allele, establishing PvM436 as a reliable marker for molecular breeding in snap beans. These findings highlight PvPW1 as a critical gene regulating pod width and underscore the utility of PvM436 in marker-assisted selection for snap bean breeding.

Genome-Wide Association for Morphological and Agronomic Traits in Phaseolus vulgaris L. Accessions.

Exploring genetic resources through genomic analyses has emerged as a powerful strategy to develop common bean (Phaseolus vulgaris L.) cultivars that are both productive and well-adapted to various environments. This study aimed to identify genomic regions linked to morpho-agronomic traits in Mesoamerican and Andean common bean accessions and to elucidate the proteins potentially involved in these traits. We evaluated 109 common bean accessions over three agricultural years, focusing on traits including the grain yield (YDSD), 100-seed weight (SW), number of seeds per pod (SDPD), number of pods per plant (PDPL), first pod insertion height (FPIH), plant height (PLHT), days to flowering (DF), and days to maturity (DPM). Using multilocus methods such as mrMLM, FASTmrMLM, FASTmrEMMA, ISIS EM-BLASSO, and pLARmEB, we identified 36 significant SNPs across all chromosomes (Pv01 to Pv11). Validating these SNPs and candidate genes in segregating populations is crucial for developing more productive common bean cultivars through marker-assisted selection.

Genetic Diversity of Common Bean (Phaseolus vulgaris L.) Landraces Based on Morphological Traits and Molecular Markers.

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.

Assessment of genotypic variability and genome‐wide association analysis of cooking time and canning quality traits in common bean (Phaseolus vulgaris L.)

AbstractDeveloping improved common bean varieties with short cooking time (CT) and good canning quality traits (CQTs) is very key for accelerating bean consumption among the urban and middle‐class population. The objective of this study was to assess the genotypic variability and identify single nucleotide polymorphism (SNP) markers associated with CT and CQTs in common bean. A total of 250 common bean accessions were evaluated under field conditions for two seasons using alpha lattice design with two replications. Three months post‐harvest, the dry bean grains were evaluated for CT and CQTs. Significant variation was observed among the 250 common bean accessions tested for both traits. CT ranged from 51 to 215 min, with 11 genotypes cooking in less than 60 min. The percentage total CQTs' score ranged from 41% to 84% with 31 genotypes scoring 76% and above. Forty‐seven significant GWAS signals were detected for CT on chromosomes Pv01, Pv04, Pv05 and Pv11 and CQTs on Pv01, Pv02, Pv03, Pv04, Pv05, Pv06, Pv07, Pv08, Pv10 and Pv11, respectively. Positional candidate genes including Phvul.005G161200 on chromosome Pv05, Phvul.007G2803001 and Phvul.007G280700 on chromosome Pv07 were associated with seed coat colour retention of the canned beans. Besides their usefulness in breeding research, the identified bean genotypes with shorter CT and good CQTs could enhance bean consumption and processing industries.

Genetic analysis of scab disease resistance in common bean (Phaseolus vulgaris) varieties using GWAS and functional genomics approaches

IntroductionScab is a fungal disease of common beans caused by the pathogen Elsinoë phaseoli. The disease results in major economic losses on common beans, and there are efforts to develop integrated pest management strategies to control the disease. Modern computational biology and bioinformatics tools were utilized to identify scab disease resistance genes in the common bean by identification of genomic regions and genes associated with resistance to scab disease during natural infection in the field.MethodsA diverse set of common bean accessions were analyzed for genetic association with scab disease resistance using a Genome-Wide Association Study design of infected plants and non-infected plants (controls). A fixed and random model circulating probability unification model of these two covariates that considers a minor allele frequency threshold value of 0.03 were deployed during the analysis. Annotation of genes proteins with significant association values was conducted using a machine learning algorithm of support vector machine on prPred using python3 on Linux Ubuntu 18.04 computing platform with an accuracy of 0.935.ResultsCommon bean accessions tested showed varying phenotypes of susceptibility to scab disease. Out of 179 accessions, 16 and 163 accessions were observed to be resistant and susceptible to scab disease, respectively. Genomic analysis revealed a significant association on chromosome one SNP S1_6571566 where the protein-coding sequence had a resistant possibility of 55% and annotated to the Enhancer of Poly-comb like protein.ConclusionThe significant differences in the phenotypic variability for scab disease indicate wide genetic variability among the common bean accessions. The resistant gene associated with scab disease was successfully identified by GWAS analysis. The identified common bean accessions resistant to scab disease can be adopted into breeding programs as sources of resistance.

Genome-wide association study dissecting drought resistance-associated loci based on physiological traits in common bean

Genetic improvement of drought resistance is one of the main breeding goals for common bean, so molecular markers must be identified to facilitate drought resistance breeding. In this study, we evaluated the proline, trehalose, raffinose, and stachyose contents of 210 common bean accessions under two watering conditions and found large variations in all four. The coefficients of variation ranged from 21.21% for proline content to 78.69% for stachyose content under well-watered conditions, and from 20.11% for proline content to 50.08% for trehalose content under drought stress. According to our genome-wide association analysis, 32 quantitative trait loci were associated with drought resistance, seven of which overlapped with known loci. Four hotspot regions were identified at Pv01, Pv07 and Pv11. A set of candidate genes was identified, including genes encoding MYB, bZIP, bHLH, ERF, and protein kinases. Among these genes, Phvul.001G189400, Phvul.007G273000 and Phvul.008G270500 were annotated as bZIP, ERF and WRKY, respectively. These genes are reportedly involved in drought stress responses in Arabidopsis thaliana and were induced by drought stress in common bean. Significant SNPs in six candidate gene regions formed different haplotypes, and phenotypic analysis revealed significant differences among the haplotypes. These results provide new insight into the genetic basis of drought resistance in common bean and reveal candidate genes and superior natural variations that will be useful for improving common bean.

Mapping of adult plant recessive resistance to anthracnose in Indian common bean landrace Baspa/KRC 8.

The common bean (Phaseolus vulgaris) has become the food of choice owing to its wealthy nutritional profile, leading to a considerable increase in its cultivation worldwide. However, anthracnose has been a major impediment to production and productivity, as elite bean cultivars are vulnerable to this disease. To overcome barriers in crop production, scientists worldwide are working towards enhancing the genetic diversity of crops. One way to achieve this is by introducing novel genes from related crops, including landraces like KRC 8. This particular landrace, found in the North Western Himalayan region, has shown adult plant resistance against anthracnose and also possesses a recessive resistance gene. In this study, a population of 179 F2:9 RIL individuals (Jawala ×KRC 8) was evaluated at both phenotypic and genotypic levels using over 830 diverse molecular markers to map the resistance gene present in KRC 8. We have successfully mapped a resistance gene to chromosome Pv01 using four SSR markers, namely IAC 238, IAC 235, IAC 259, and BM 146. The marker IAC 238 is closely linked to the gene with a distance of 0.29cM, while the other markers flank the recessive resistance gene at 10.87cM (IAC 259), 17.80cM (BM 146), and 25.22cM (IAC 235). Previously, a single recessive anthracnose resistance gene (co-8) has been reported in the common bean accession AB 136. However, when we performed PCR amplification with our tightly linked marker IAC 238, we got different amplicons in AB 136 and KRC 8. Interestingly, the susceptible cultivar Jawala produced the same amplicon as AB 136. This observation indicated that the recessive gene present in KRC 8 is different from co-8. As the gene is located far away from the Co-1 locus, we suggest naming the recessive gene co-Indb/co-19. Fine mapping of co-Indb in KRC 8 may provide new insights into the cloning and characterization of this recessive gene so that it can be incorporated into future bean improvement programs. Further, the tightly linked marker IAC 238 can be utilized in marker assisted introgression in future bean breeding programs. The novel co-Indb gene present in Himalayan landrace KRC 8, showing adult plant resistance against common bean anthracnose, is independent from all the resistance genes previously located on chromosome Pv01.

The alleles bc-ud and bc-ur (previously bc-4 gene), representing coding mutations within Vps4 AAA+ ATPase ESCRT protein, interact with other genes to condition resistance to BCMV and BCMNV in common bean.

Bean common mosaic virus (BCMV) and bean common mosaic necrosis virus (BCMNV) have a damaging impact on global common bean (Phaseolus vulgaris L.) cultivation, causing potential yield losses of over 80%. The primary strategy for controlling these viruses is through host plant resistance. This research aimed to identify and validate structural variations for the bc-ud gene as revealed by long-read sequencing, develop an efficient DNA marker to assist selection of bc-ud in snap and dry beans, and examine the interactions between the bc-ud allele and other BCMV resistance genes. A gene (Phvul.005G125100) model on chromosome Pv05, encoding a vacuolar protein-sorting 4 (Vps4) AAA+ ATPase endosomal sorting complexes required for transport (ESCRT) protein, was identified as the best candidate gene for bc-ud. An 84-bp repetitive insertion variant within the gene, exhibited 100% co-segregation with the bc-ud resistance allele across 264 common bean accessions. The 84-bp repetitive insertion was labeled with an indel marker IND_05_36225873 which was useful for tracking the bc-ud allele across diverse germplasm. A different single nucleotide polymorphism variant within the same candidate gene was associated with the bc-4 gene. Segregation in F2 populations confirmed bc-ud and bc-4 were alleles, so bc-4 was renamed bc-ur to fit gene nomenclature guidelines. The interactions of bc-ud and bc-ur with other resistance genes, such as bc-1 (receptor-like kinase on Pv03) and bc-2 (Vps4 AAA+ ATPase ESCRT protein on Pv11), validated gene combinations in the differential "host groups" effective against specific BCMV/BCMNV "pathogroups." These findings increase our understanding of the Bc-u locus, and enhance our ability to develop more resilient bean varieties through marker-assisted selection, reducing the impact of BCMV and BCMNV.

Productivity and growing-season stability in common bean (Phaseolus vulgaris L.) under contrasting ecogeographic conditions

Background. Studying the effect size of the environment versus breeding-oriented plant traits is relevant under climate change. Identification of stable accessions while evaluating the source material in contrasting environments can increase the efficiency of breeding practice.Materials and methods. Thirty common bean accessions from the VIR collection were sown for 3 years in the contrasting environments of Maikop and Astrakhan. Eight useful agronomic traits were studied according to VIR’s guidelines. Statistical processing was carried out using ANOVA, correlation and regression analyses. Environmental stability of productivity was assessed according S. A. Eberhart and W. A. Russell (1966).Results and discussion. The study of the variability of traits showed the stability of the sowing-to-ripening period duration (average coefficient of variation: 10.9%) and 1000 seed weight (17.3%). The effect of the genotype was the determining factor only for 1000 seed weight (67.6% of the variance). The growing season duration, number of pods per plant, number of seeds per pod, and productivity depended more on the environments. Productivity formation patterns were basically the same at both sites: productivity of an accession depended on the number of pods, and 1000 seed weight was negatively related to the number of seeds per pod. The growing season in Maikop depended on the flowering-to-ripening period (r = 0.73); in Astrakhan, on the sprouting-to-flowering period (r = 0.85). The duration of the sowing-to-sprouting and sprouting-to-flowering periods significantly correlated with mean temperatures (r = –0.87 and 0.87, respectively), while the flowering-to-ripening period did not depend on the mean temperature.Conclusion. Accessions relatively stable in their productivity and duration of the growing season were identified. They demonstrated both determinant and indeterminate growth, attesting to the prospects of breeding work with different common bean groups.

Genome-Wide Association Study and Genomic Prediction of Fusarium Wilt Resistance in Common Bean Core Collection.

The common bean (Phaseolus vulgaris L.) is a globally cultivated leguminous crop. Fusarium wilt (FW), caused by Fusarium oxysporum f. sp. phaseoli (Fop), is a significant disease leading to substantial yield loss in common beans. Disease-resistant cultivars are recommended to counteract this. The objective of this investigation was to identify single nucleotide polymorphism (SNP) markers associated with FW resistance and to pinpoint potential resistant common bean accessions within a core collection, utilizing a panel of 157 accessions through the Genome-wide association study (GWAS) approach with TASSEL 5 and GAPIT 3. Phenotypes for Fop race 1 and race 4 were matched with genotypic data from 4740 SNPs of BARCBean6K_3 Infinium Bea Chips. After ranking the 157-accession panel and revealing 21 Fusarium wilt-resistant accessions, the GWAS pinpointed 16 SNPs on chromosomes Pv04, Pv05, Pv07, Pv8, and Pv09 linked to Fop race 1 resistance, 23 SNPs on chromosomes Pv03, Pv04, Pv05, Pv07, Pv09, Pv10, and Pv11 associated with Fop race 4 resistance, and 7 SNPs on chromosomes Pv04 and Pv09 correlated with both Fop race 1 and race 4 resistances. Furthermore, within a 30 kb flanking region of these associated SNPs, a total of 17 candidate genes were identified. Some of these genes were annotated as classical disease resistance protein/enzymes, including NB-ARC domain proteins, Leucine-rich repeat protein kinase family proteins, zinc finger family proteins, P-loopcontaining nucleoside triphosphate hydrolase superfamily, etc. Genomic prediction (GP) accuracy for Fop race resistances ranged from 0.26 to 0.55. This study advanced common bean genetic enhancement through marker-assisted selection (MAS) and genomic selection (GS) strategies, paving the way for improved Fop resistance.

Oligogenic control of quantitative resistance against powdery mildew revealed in Portuguese common bean germplasm.

Common bean (Phaseolus vulgaris L.) is one of the most important food legumes worldwide, being its production severely affected by fungal diseases such as powdery mildew. Portugal has a diverse germplasm, with accessions of Andean, Mesoamerican, and admixed origin, making it a valuable resource for common bean genetic studies. In this work, we evaluated the response of a Portuguese collection of 146 common bean accessions to Erysiphe diffusa infection, observing a wide range of disease severity and different levels of compatible and incompatible reactions, revealing the presence of different resistance mechanisms. We identified 11 incompletely hypersensitive resistant, and 80 partially resistant accessions. We performed a genome-wide association study to clarify its genetic control, resulting in the identification of eight disease severity-associated single-nucleotide polymorphisms, spread across chromosomes Pv03, Pv09, and Pv10. Two of the associations were unique to partial resistance, and one to incomplete hypersensitive resistance. The proportion of variance explained by each association varied between 15 and 86%. The absence of a major locus, together with the relatively small number of loci controlling disease severity (DS), suggested an oligogenic inheritance of both types of resistance. Seven candidate genes were proposed including a disease resistance protein (TIR-NBS-LRR class), an NF-Y transcription factor complex component, and an ABC-2 type transporter family protein. This work contributes with new resistance sources and genomic targets valuable to develop selection molecular tools and support powdery mildew resistance precision breeding in common bean.

Assessing anthracnose resistance in common bean accessions: identification of resistance genes using SCAR markers against Colletotrichum lindemuthianum

Assessing anthracnose resistance in common bean accessions: identification of resistance genes using SCAR markers against Colletotrichum lindemuthianum

Genomic prediction for drought tolerance using multienvironment data in a common bean (Phaseolus vulgaris) breeding program

AbstractThis work evaluated the efficiency of different genomic prediction (GP) methods in a diverse Mesoamerican panel of 339 common bean accessions, genotyped with 3398 SNP markers. Field experiments were carried out for three consecutive years, with adequate water supply (non‐stress—NS) and water restriction imposition (water‐stress—WS), analyzing seed weight (SW) and grain yield (GY). Two methods to predict the accuracies (rĝg) were adopted (GBLUP and Bayes) and also considered the environmental variation (GBLUP‐based reaction norm model). Similar accuracies were observed for both methods. For GY, the highest rĝg were detected under NS (rĝg = 0.49) in 2016 (rĝg = 0.49) and in the joint analysis for the WS condition (rĝg = 0.33), both for models using local landraces. For SW under NS, the rĝg was higher for the elite lines (rĝg = 0.72), whereas for WS, the rĝg dropped considerably, ranging from 0.45 to 0.61 for the joint analysis, considering the landraces and all samples, respectively. For GY and SW, under NS, the rĝg using both models increased with increasing number of SNPs, until reaching a plateau of 800 and 300 SNPs, respectively. Increasing the training population (TP) size resulted in greater accuracy. Taking in account the Genotype × Environment, the multienvironment model performed better especially for more complex traits (GY/NS: rĝg = 0.32). The GP approach has great potential to help commercial bean breeding programs improving the performance of target quantitative traits.

Assessment of genetic diversity and population structure of Indian common bean accessions using microsatellite markers

AbstractCommon bean (Phaseolus vulgaris L.) is an important crop of family Fabaceae used as a potential source of proteins, fibres and minerals. Thus, characterization of existing germplasm is useful for improvement and conservation. The Indian Himalayan Region harbours plentiful varieties of common bean, but it is nearly unexplored till date. In the present study, physical and genetic diversity of common bean was examined. Fifteen newly designed chloroplast microsatellite (cpSSR) markers were used to assess genetic diversity and population structure in 119 common bean individuals from 20 diverse accessions gathered from Uttarakhand, India. Significantly, positive (p< 0.05) relationship of seed weight was found with seed length (r = 0.813), seed width (r = 0.692) and seed length- width ratio (r = 0.694) using Pearson correlation analysis. A total of 20 alleles were identified using eight cpSSR markers. Mean number of alleles per locus (Na = 1.55), effective allele number (Ne = 1.370), expected heterozygosity (He = 0.213), average polymorphic loci (10.9) and Shannon information index (I = 0.313) were estimated based on cpSSR data. Maximum genetic diversity (He) was recorded in the AKJ/KK/DP/Jhalla/23 accession and minimum in the AKJ/YB/PS/Supi/43 accession. Bayesian-based STRUCTURE evaluation using cpSSR-based information partitioned 20 accessions into two distinct clusters which were also supported by neighbor-joining cluster analysis. These cpSSR markers also demonstrated transferability among other members like Vigna radiata, Macrotyloma uniflorum, Glycine max, Vigna mungo of Fabaceae family, therefore can be used to monitor their genetic heterogeneity. The findings from the study might be valuable to identify elite common bean accessions for production, conservation and future breeding programmes.

Transcriptomic and metabolomic analysis reveals that symbiotic nitrogen fixation enhances drought resistance in common bean.

Common bean (Phaseolus vulgaris L.), one of the most important legume crops, use atmospheric nitrogen through symbiosis with soil rhizobia reducing the nitrogen fertilization needs. However, this legume is particularly sensitive to drought conditions, prevalent in arid regions where this crop is cultured. Therefore, studying the response to drought is important to sustain crop productivity. We have used integrated transcriptomic and metabolomic analysis to understand the molecular responses to water deficit in a marker-class common bean accession cultivated under N2-fixation or fertilized with nitrate (NO3-). RNA-seq revealed more transcriptional changes in the plants fertilized with NO3- than in the N2-fixing plants. However, changes in N2-fixing plants were more associated with drought tolerance than in the NO3- fertilized ones. N2-fixing plants accumulated more ureides in response to drought and GC/MS and LC/MS analysis of primary and secondary metabolites profiles revealed that N2-fixing plants also had higher levels of ABA, proline, raffinose, amino acids, sphingolipids and triacylglycerols than the NO3- fertilized ones. Moreover, plants grown under nitrogen fixation recovered from drought better than plants fertilized with NO3-. Altogether we show that common bean plants grown under symbiotic nitrogen fixation were more protected against drought than the plants fertilized with nitrate.

English

Characterization and conservation of germplasm is a critical step toward the genetic improvement of the crop. This study assessed variation in 257 common bean genotypes which included 207 accessions obtained the National Gene Bank of Kenya, 33 accessions from Kenya Agricultural and Livestock Research Organization (KALRO), 13 landraces collected from farmers’ fields and four commercial varieties for various agronomic traits. The experiments were laid out in a randomized complete block design with three replicates at Jomo Kenyatta University of Agriculture and Technology (Kenya) for four seasons between 2019 and 2020. Significant differences (P≤0.05) existed among the common bean accessions for all traits studied. Seed yield ranged from 220.6 to 4641.9 kg/ha (KNB0106) among the accessions with a mean of 1267.0 kg/ha. Significant (P ≤0.05) positive correlation was recorded for days to flowering and days to maturity (0.73), while 100-seed weight had a significantly negative correlation with the number of pods per plant (-0.66) and the number of seeds per pod (-0.65). High (>20%) broad-sense heritability was recorded for 100-seed weight (89.0%), days to flowering (76.8%), and grain yield (60.5%). Nineteen accessions that combined early maturity and high-yielding traits were identified. On average, higher seed yields were recorded for large-seeded and climbing genotypes compared to small-seeded and bush types. Common bean accessions characterized can be exploited in breeding programs. Key words: Common bean, agronomic traits, Phaseolus vulgaris, variability, broad sense heritability.

Genome‐wide association study of variation in cooking time among common bean (Phaseolus vulgaris L.) accessions using Diversity Arrays Technology markers

AbstractStored grains of common bean (Phaseolus vulgaris L.) develop the hard‐to‐cook trait (HTC), which is manifested in a prolonged cooking time, thereby imposing time and energy constraints. The objective of this study was to determine variation in cooking time among common bean genotypes and to identify single nucleotide polymorphism (SNP) markers associated with cooking time.Seeds of 222 common bean accessions sourced from Kenyan institutions were multiplied in the Jomo Kenyatta University of Agriculture and Technology (JKUAT) field in 2019. The freshly harvested seeds and those stored at 35°C and 50% red haricot (RH) for 4 months for accelerated aging were soaked in distilled water for 16 h and evaluated for cooking time using the finger‐pressing method. The accessions were also genotyped to determine variation in SNP markers using Diversity Arrays Technology Sequencing (DArTseq). Genome‐wide association study (GWAS) analysis was conducted to identify SNPs significantly associated with cooking time.The study revealed significant differences (p ≤ 0.05) within and between fresh and aged bean accessions. Fresh seeds had a lower cooking time with a mean of 40.8 min and ranged from 28.1 to 72.2 min, whereas aged seeds had a higher average cooking time of 54.1 min and ranged from 32.1 to 96.3 min. GWAS identified a region in Chromosome 10 to be significantly (p ≤ 0.05) associated with the cooking time of aged seeds. Consequently, two potential candidate genes Phvul.010G038000 and Phvul.010G038100 were revealed. The characterized common bean accessions and the identified SNP markers can be utilized in breeding programs to improve the cooking quality of the common bean.

Study of genetic diversity and search for anthracnose resistance alleles in common bean (Phaseolus vulgaris L.) genotypes cultivated in Azerbaijan

Common bean has become very popular and widespread among the population since its introduction to Azerbaijan in the second half of the 18th century. The paper represents for the first time the genetic diversity and anthracnose resistance of 37 common bean accessions cultivated in Azerbaijan. ISSR marker characterization in the present study revealed a total of 47 bands, with 33.6% of average polymorphism. The polymorphism information content (PIC) and genetic diversity index (GDI) for each primer were in the range of 0.25-0.48 (mean 0.35) and 0.45-0.73 (mean 0.59), respectively, indicating a moderate level of genetic diversity in the current collection. UNJ tree showed that the common bean accessions tended to cluster according to the local and introduced gene pools, indicating the same original sources of these accessions, which is also supported by PCo analysis. Screening with linked SCAR markers revealed the existence of common bean genotypes with single or multiple Co resistance alleles. Among studied genes Co-4 locus and its alleles were found in all samples, followed by Co-6 (40.5%) and Co-34 (16%). Three genotypes had all studies resistance loci, while 12 had Co-4 and Co-6, and 3 had Co-4 and Co-34. The results could provide valuable information for future common bean breeding activities and conservation. The use of genotypes with two or more resistance genes as donor parents can accelerate the development of new common bean cultivars with durable resistance to anthracnose.

Caracterização molecular de acessos de feijão comum por meio de marcadores microssatélites

ABSTRACT The common bean, a legume of significant economic importance, is renowned for its extensive genetic variability. It is crucial to comprehend genetic diversity, analyze population structure, and understand relationships among commercial classes of accessions to facilitate genetic improvement. This study aimed to molecularly characterize 143 common bean accessions by employing 25 SSR molecular markers. The objectives were to estimate genetic diversity, analyze genetic structure, and cluster populations using the UPGMA and PCoA methods. A total of 105 alleles were amplified using microsatellite loci, and the observed heterozygosity was lower than expected across all loci, indicating inbreeding within the populations. Among the loci, 22 were highly informative, demonstrating their effectiveness and polymorphism in detecting genetic diversity. The genetic variability within the population was found to be the highest, while variation between populations was the lowest. The analysis of population structure revealed the presence of three populations with a notable rate of gene introgression. The UPGMA analysis categorized the accessions into 15 groups, but they did not form distinct clusters based on their geographic regions or gene pool. The first two principal coordinates accounted for 13.95% of the total variation among the accessions. The SSR markers employed effectively detected genetic variability among the common bean accessions, revealing that their genetic diversity was not correlated with their geographic distribution in this study.

Genetic dissection of yield-related traits in response to drought stress in common bean

Drought stress severely impairs common bean production. For facilitating drought-resistance breeding in common bean, molecular markers were identified in a genome-wide level marker–trait association study. A panel of 210 common bean accessions showed large variation in 11 agronomic traits at the adult stage (plant height, pod number per plant, seed number per pod, seed number per plant, seed yield per plant, pod length, harvest index, pod harvest index, days to maturity, hundred-seed weight, and seed yield) under two water conditions. The coefficient of variation ranged from 6.21% for pod harvest index to 51.00% for seed number per plant under well-watered conditions, and from 4.05% for days to maturity to 40.72% for seed number per plant under drought stress. In a genome-wide association study, 119 quantitative-trait loci were associated with drought resistance, including 41 adjacent to known loci. Among these loci, 12 were found to be associated with at least two traits. Three major loci were identified at Pv01 and Pv02. A set of candidate genes were found that encode MYBs, AREBs, WKRYs, and protein kinases. These results reveal promising alleles that control drought resistance, shedding light on the genetic basis of drought resistance and accelerating future efforts for drought resistance improvement in common bean.