Pepper Diseases in Balkan Region

One of the most important problems affecting pepper production in the Balkan peninsula is the occurrence of common pathogens causing severe diseases and epidemics resulting in reduced and compromised yield. In the last years new pepper fungal pathogens (Phomopsis capsid and several Colletooichum spp.) were found in Bulgaria with increasingly frequency. In 20lO a SEE-ERA.NET project started combining the research efforts of 7 scientific institutions from 5 Balkan countries (Albania, Bulgalia, FYR Macedonia, Greece and Serbia)

Characterization of Tomato Accessions for Morphological, Agronomic, Fruit Quality, and Virus Resistance Traits

Characterization of local germplasm is an effective way to identify elite breeding material and develop improved varieties. This study was aimed to assess 52 tomato accessions comprised of local varieties (28), landraces (8), breeding lines (14), and wild relatives (2) and its characterization for 30 morphological/agronomic, four fruit quality, and Tomato Mosaic Virus (ToMV) resistance traits. Morphological, quality, and ToMV traits were evaluated using phenotyping, biochemical assays, and molecular markers, respectively. Fruit shape and size showed appreciable variation with fruits varied from rounded to heart shape and small to big size. Significant variation was observed for fruit weight (1.6g to 564.8g), fruits per plant (6.0 to 174.7), productivity (130.5g to 5146.5g), soluble solids (4.1% to 8.4%), vitamin C (9.5 mg/100g to 46.4 mg/100g), antioxidant activity (2.5 μmol Fe2+/g FW to 9.6 μmol Fe2+/g FW), and total polyphenols (23.9 GAE/100g FW to 124.2 GAE/100g FW). All accessions were phenotypically screened for the virus resistance in the growth chamber and CAPS molecular markers were used to identify accessions with ToMV Tm-22 resistant alleles and accessions LYC-13, LYC-15, LYC-17, LYC-26, and LYC-52 were identified as resistant. Multivariate analysis of morphological and quality traits showed that 35 principal components (PCs) contributed to the total variation and the first two and twelve PCs explained 47.2% and 90% variation, respectively. The evaluated tomato collection appears to have breeding potential and around 20% accessions of the collection (LYC-6, LYC 17-18, LYC 26-31, LYC 33) are promising genetic resources for variety development that are enriched with enhanced fruit quality and high yield.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Double Haploid Development and Assessment of Androgenic Competence of Balkan Pepper Core Collection in Bulgaria

This study was designed to assess the androgenic potential of 180 pepper accessions and 11 progenies (four F1 and seven BC) possessing PMMoV resistance in order to complement an ongoing pepper breeding program. The experiment was carried out in 10 replications with 20 anthers for each accession in two different induction mediums from 2017 to 2019. The highest androgenic response was observed in culture medium 17-2 but differences between two mediums were nonsignificant. From a total of 191 genotypes, 102 genotypes expressed a potential for direct embryogenesis. Embryo induction was seen to be genotype-dependent and decreased in the following order: Pumpkin > Conical > Bell or blocky > Round > Elongate as the most responsive genotypes with over 10% reacted anthers being observed in CAPS-23, CAPS-29, CAPS-127, CAPS-157, CAPS-169, F1 and BC 887 derived from CAPS-23. The number of regenerated plants was higher in the conical group and least in the round varietal group. Regenerated plants were examined visually and by flow cytometry for identification of spontaneous doubled haploids (DH) and haploids. Those originating from F1 and BC progenies were additionally evaluated by a CAPS marker targeting L4 allele for resistance against PMMoV. Obtained results revealed two groups consisting of homozygous susceptible and resistant plants. Therefore, use of anther culture in ongoing breeding will greatly facilitate the pepper genetic improvement

A step towards Balkan Capsicum annuum L. core collection: Phenotypic and biochemical characterization of 180 accessions for agronomic, fruit quality, and virus resistance traits.

Region-specific local landraces represent a germplasm diversity adapted and acclimatized to local conditions, and are ideal to breed for targeted market niches while maintaining the variability of heirloom traits. A collection of 180 pepper accessions, collected from 62 diverse locations across six Balkan countries, were characterized and evaluated for phenotypic and biochemical variation during a multi-year environment. An assortment of 32 agro-morphological, fruit quality, and virus resistance traits were evaluated, and the top 10% accessions were identified. A wide range of trait variation concerning plant architecture, inflorescence and fruit traits, yield and fruit quality was observed, and appreciable variation was noticed. According to hierarchical clustering, six distinct clusters were established based on pre-defined varietal groups. Divergence among accessions for phenotypic and fruit compositional variability was analyzed, and eight principal components were identified that contributed ~71% of the variation, with fruit shape, width, wall thickness, weight, and fruit quality traits being the most discriminant. Evaluation of the response to tobacco mosaic virus (TMV) and pepper mild mottle mosaic virus (PMMoV) showed that 24 and 1 accession were resistant, respectively while no tomato spotted wilt virus (TSWV) resistance was found. Considerable diversity for agro-bio-morphological traits indicates the Balkan pepper collection as good gene sources for pre-breeding and cultivar development that are locally adapted

Exploration of high‐throughput data for heat tolerance selection in Capsicum annuum

Abstract Recently, there has been a substantial increase in high‐throughput technologies that generate highly complex large datasets for use in the sciences. Plant breeding and genetics have benefited from this data explosion where many public and private institutions now implement genomic and phenomic data to predict performance thus informing germplasm selection. However, the multitude of methodologies and data generates a situation of strategic uncertainty. We set out to compare different methods of genomic and phenomic selection in the Capsicum core collection, developed through the G2P‐SOL project, producing a combination of unique and similar selected genotypes for heat tolerance. Combined, the methods tested identified a total of 33 genotypes that show tremendous promise for use as parents in heat tolerance breeding: with 13 of these being present in more than 1 selection method. Combining classical and multispectral phenotyping methods produced better selection results than either method alone. When each method was conducted without being informed by the other, similar results were obtained. Our weighted rank‐sum selection index identified 10 entries across environments that show heat tolerance, 8 of which are also selected within heat environments. This suggests that different breeding programs can reach similar results despite having different logistical constraints. Our case study within pepper germplasm using phenomic and genomic data exhibits the potential to compensate for the dearth of germplasm knowledge with high‐throughput data as well as the converse, to compensate for logistical or financial constraint to new technologies with breeder knowledge

Exploration of high-throughput data for heat tolerance selection in Capsicum annuum

Recently, there has been a substantial increase in high-throughput technologies that generate highly complex large datasets for use in the sciences. Plant breeding and genetics have benefited from this data explosion where many public and private institutions now implement genomic and phenomic data to predict performance thus informing germplasm selection. However, the multitude of methodologies and data generates a situation of strategic uncertainty. We set out to compare different methods of genomic and phenomic selection in the Capsicum core collection, developed through the G2P-SOL project, producing a combination of unique and similar selected genotypes for heat tolerance. Combined, the methods tested identified a total of 33 genotypes that show tremendous promise for use as parents in heat tolerance breeding: with 13 of these being present in more than 1 selection method. Combining classical and multispectral phenotyping methods produced better selection results than either method alone. When each method was conducted without being informed by the other, similar results were obtained. Our weighted rank-sum selection index identified 10 entries across environments that show heat tolerance, 8 of which are also selected within heat environments. This suggests that different breeding programs can reach similar results despite having different logistical constraints. Our case study within pepper germplasm using phenomic and genomic data exhibits the potential to compensate for the dearth of germplasm knowledge with high-throughput data as well as the converse, to compensate for logistical or financial constraint to new technologies with breeder knowledge

Global range expansion history of pepper (Capsicum spp.) revealed by over 10,000 genebank accessions

Genebanks collect and preserve vast collections of plants and detailed passport information, with the aim of preserving genetic diversity for conservation and breeding. Genetic characterization of such collections has the potential to elucidate the genetic histories of important crops, use marker-trait associations to identify loci controlling traits of interest, search for loci undergoing selection, and contribute to genebank management by identifying taxonomic misassignments and duplicates. We conducted a genomic scan with genotyping by sequencing (GBS) derived single nucleotide polymorphisms (SNPs) of 10,038 pepper (Capsicum spp.) accessions from worldwide genebanks and investigated the recent history of this iconic staple. Genomic data detected up to 1,618 duplicate accessions within and between genebanks and showed that taxonomic ambiguity and misclassification often involve interspecific hybrids that are difficult to classify morphologically. We deeply interrogated the genetic diversity of the commonly consumed Capsicum annuum to investigate its history, finding that the kinds of peppers collected in broad regions across the globe overlap considerably. The method ReMIXTURE-using genetic data to quantify the similarity between the complement of peppers from a focal region and those from other regions-was developed to supplement traditional population genetic analyses. The results reflect a vision of pepper as a highly desirable and tradable cultural commodity, spreading rapidly throughout the globe along major maritime and terrestrial trade routes. Marker associations and possible selective sweeps affecting traits such as pungency were observed, and these traits were shown to be distributed nonuniformly across the globe, suggesting that human preferences exerted a primary influence over domesticated pepper genetic structure