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.

No abstract

A total of 38 eggplant genotypes, of which 32 were heirloom accessions collected from different regions of Burdur province five were different local genotypes from other provinces, and one was a cultivar, were used as reference in this study. The phylogenetic relationships among these heirlooms were evaluated using 40 morphologic descriptors and five randomly amplified polymorphic RAPD markers. The horizontal dendrograms were created by using UPGMA with both morphologic and molecular data. Burdur heirloom accessions showed high genetic diversity based on morphological and molecular data. The genetic similarity rates ranged from 0.29 to 0.91 according to the morphological data, and ranged from 0.84 to 0.98 according to the molecular data. Molecular data generated by RAPD method, compared to morphological data, were insufficient to reveal genetic diversity. Therefore, in order to confirm genetic variations, studies based on other molecular methods are necessary. The regional genetic populations include a wide eggplant genetic diversity which can be good source for the breeding studies performed in the future.

Clavibacter michiganensis subsp. michiganensis (Cmm) is one of the phytopathogenic bacteria causing bacterial wilt disease and severe yield losses in tomatoes and other solanaceous vegetables. Although there are some reports on Cmm infections in eggplants (Solanum melongena), there is no information available on the resistance sources and genetic control of the resistance to Cmm in this crop. We performed a search for resistance sources to Cmm in eggplants, in a set of 46 genotypes including landraces, inbred lines and cultivars and some cultivated and wild relatives, as well as an analysis of the genetic control of the resistance. A mixture of different Cmm strains from different genomic groups was used for the screening. Plants were inoculated through the injection of 10 µL of a Cmm suspension at a concentration of 10⁷ cfu/mL in a single point of the stem. The symptoms were recorded at nine weeks after the inoculation with a 0–4 symptoms scale. The differences were observed in the symptoms in the collection evaluated, with the disease severity index of the genotypes ranging from 0.00 to 4.00. While 31 genotypes displayed no symptoms, three cultivated eggplant genotypes were highly susceptible. Reciprocal F1 and F2 generations were obtained from the crosses between the most susceptible genotype (CT30) and a resistant one (CT49). The genetic control of the resistance adjusted well to one dominant and one recessive gene model underlying the resistance to Cmm. These results are important for selection and breeding for resistance to Cmm in eggplants.

No abstract