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Abstract Background Anthracnose is a fungal disease caused by Colletotrichum spp. that has a significant impact on worldwide pepper production. Colletotrichum scovillei is the most common pathogenic anthracnose-causing species in the Republic of Korea. Results The resistances of 197 pepper (Capsicum chinense) accessions deposited in Korea’s National Agrobiodiversity Center were evaluated for their response against the virulent pathogens Colletotrichum acutatum isolate ‘KSCa-1’ and C. scovillei isolate ‘Hana’) in the field and in vitro methods for three consecutive years (2018 to 2020). The severity of the disease was recorded and compared between inoculation methods. Six phenotypically resistant pepper accessions were selected based on three years of disease data. All of the selected resistant pepper accessions outperformed the control resistant pepper in terms of resistance (PI 594,137). A genome-wide association study (GWAS) was carried out to identify single nucleotide polymorphisms (SNPs) associated with anthracnose resistance. An association analysis was performed using 53,518 SNPs and the disease score of the 2020 field and in vitro experiment results. Both field and in vitro experiments revealed 25 and 32 significantly associated SNPs, respectively. These SNPs were found on all chromosomes except Ch06 and Ch07 in the field experiment, whereas in the in vitro experiment they were found on all chromosomes except Ch04 and Ch11. Conclusion In this study, six resistant C. chinense accessions were selected. Additionally, in this study, significantly associated SNPs were found in a gene that codes for a protein kinase receptor, such as serine/threonine-protein kinase, and other genes that are known to be involved in disease resistance. This may strengthen the role of these genes in the development of anthracnose resistance in Capsicum spp. As a result, the SNPs discovered to be strongly linked in this study can be used to identify a potential marker for selecting pepper material resistant to anthracnose, which will assist in the development of resistant varieties.

Abstract The coconut palm or “tree of life” is one of nature’s most useful plants and the demand for its fruit is increasing. However, coconut production is threatened by ageing plantations, pests and diseases. Currently, the palm is exclusively propagated via seeds, limiting the amount of planting material. A novel micropropagation method is presented, based on axillary shoot formation. Apical meristems of in vitro coconut seedlings are cultured onto Y3 medium containing 1 µM TDZ. This induces the apical meristem to proliferate through axillary shoots in ~ 27% of the initiated explants. These axillary shoots are seen as white clumps of proliferating tissue and can be multiplied at a large scale or regenerated into rooted in vitro plantlets. This innovative micropropagation method will enable the production of disease-free, high quality in vitro plantlets, which will solve the worldwide scarcity of coconut planting material.

One of the most serious pepper diseases is Phytophthora blight, which is caused by Phytophthora capsici. It is crucial to assess the resistance of pepper genetic resources to Phytophthora blight, understand the genetic resistances, and develop markers for selecting resistant pepper materials in breeding programs. In this study, the resistance of 342 pepper accessions to P. capsici was evaluated. The disease severity score method was used to evaluate the phenotypic responses of pepper accessions inoculated with the KCP7 isolate. A genome-wide association study (GWAS) was performed to identify single nucleotide polymorphisms (SNPs) linked to P. capsici (isolate KCP7) resistance. The pepper population was genotyped using the genotype-by-sequencing (GBS) method, and 45,481 SNPs were obtained. A GWAS analysis was performed using resistance evaluation data and SNP markers. Significantly associated SNPs for P. capsici resistance at 4 weeks after inoculation of the GWAS pepper population were selected. These SNPs for Phytophthora blight resistance were found on all chromosomes except Chr.05, Chr.09, and Chr.11. One of the SNPs found on Chr.02 was converted into a high-resolution melting (HRM) marker, and another marker (QTL5-1) from the previous study was applied to pepper accessions and breeding lines for validation and comparison. This SNP marker was selected because the resistance phenotype and the HRM marker genotype matched well. The selected SNP was named Chr02-1126 and was located at 112 Mb on Chr.02. The Chr02-1126 marker predicted P. capsici resistance with 78.5% accuracy, while the QTL5-1 marker predicted resistance with 80.2% accuracy. Along with the marker for major quantitative traits loci (QTLs) on Chr.05, this Chr02-1126 marker could be used to accurately predict Phytophthora blight resistance in pepper genetic resources. Therefore, this study will assist in the selection of resistant pepper plants in order to breed new phytophthora blight-resistant varieties.

This study monitored changes in major carotenoids (lutein, ⍺-carotene, and β-carotene), free sugars (fructose, glucose, and sucrose), ascorbic acid, vitamin E, phytosterols (campesterol, stigmasterol, and β-sitosterol), fatty acid composition, total phenol content (TPC), total flavonoid content (TFC), total anthocyanin content, and antioxidant activities (AA); ferric-reducing antioxidant power (FRAP) and 2,2′-azino-bis (3-ethylbenzothiazoline-6sulfonic acid) [ABTS] assays, in the inner and outer root tissues of nine carrot genotypes with orange, white, and purple roots. The results showed a differential accumulation of bioactive compounds and antioxidant activities depending on root tissue and color. Carotenoids, free sugars, and total phytosterol contents were higher in genotypes with orange roots than in other genotypes. Ascorbic acid, TPC, TFC, total anthocyanin, and AA were highest in purple-colored carrots while vitamin E content was higher in white/purple carrots. Root color was highly related to the accumulation of individual carotenoids, vitamin E isomers, and total anthocyanin content most prominently among the analyzed bioactive compounds and AA. Free sugar and carotenoid contents were relatively higher in outer tissues than in inner tissues. Furthermore, ascorbic acid, TPC, TFC, and AA were statistically higher or similar in outer tissues when compared to inner tissues in all genotypes. In contrast, trends in vitamin E and phytosterol content were inconsistent between the inner and outer tissues, depending on the genotype. Although fatty acid composition was affected by both root color and tissue, the results were not significant. Thus, the phytochemical profile and content were highly dependent on root color and tissue in carrot genotypes. This may be useful in the food processing and pharmaceutical industries for the extraction of targeted bioactive compounds.

Carrot (Daucus carota), one of the most economically important root vegetables, shows a wide range of morphological and biochemical diversity. However, there is a lack of simultaneous systematic study regarding the biochemical composition and morphological characteristics in carrot genetic resources, which is crucial for crop improvement. For this reason, the morphological characteristics, carotenoids, and free sugar content of 180 carrot genetic resources grown in open field conditions from March to June 2020 were accessed to select the lines for a potential breeding program. Altogether, 15 qualitative and 4 quantitative agronomical characteristics were evaluated and grouped into four categories based on root color (orange, yellow, white, and purple). Three carotenoids (lutein, α-carotene, and β-carotene) and three free sugars (fructose, glucose, and sucrose) were also analyzed. The results revealed wide genetic variation in both qualitative and quantitative traits. Most of the genetic resources were orange (n = 142), followed by white (n = 16), yellow (n = 14), and purple (n = 8). Carotenoid profile and content were highly dependent on root color and showed wide genetic variability, while sugar content and profile were independent of the root color. Alpha- and β- carotene were the major carotenoids in orange carrots representing 43.3 and 41.0% of total carotenoids. In contrast, lutein was most dominant in other colored carrots (79.7–98.6% of total carotenoids). In most of the genetic resources, sucrose was the most dominant free sugar, followed by glucose and fructose. The results of this study showed that some genetic resources elevated carotenoid and sugar content. The morphological and biochemical diversity observed in this study might be useful for improving the agronomic traits and biochemical content of carrot lines for breeding programs.

Individual glucosinolates (GSLs) were assessed to select cabbage genotypes for a potential breeding program. One hundred forty-six cabbage genotypes from different origins were grown in an open field from March to June 2019; the cabbage heads were used for GSL analyses. Seven aliphatics [glucoiberin (GIB), progoitrin (PRO), epi-progoitrin (EPI), sinigrin (SIN), glucoraphanin (GRA), glucoerucin (GER) and gluconapin (GNA)], one aromatic [gluconasturtiin (GNS)] and four indolyl GSLs [glucobrassicin (GBS), 4-hydroxyglucobrassicin (4HGBS), 4-methoxyglucobrassicin (4MGBS), neoglucobrassicin (NGBS)] were found this study. Significant variation was observed in the individual GSL content and in each class of GSLs among the cabbage genotypes. Aliphatic GSLs were predominant (58.5%) among the total GSLs, followed by indolyl GSL (40.7%) and aromatic GSLs (0.8%), showing 46.4, 51.2 and 137.8% coefficients of variation, respectively. GIB, GBS and NGBS were the most common GSLs found in all genotypes. GBS was the most dominant GSL, with an average value of 3.91 µmol g−1 (0.79 to 13.14 µmol g−1). SIN, GIB, PRO and GRA were the other major GSLs, showing average values of 3.45, 1.50, 0.77 and 0.62 µmol g−1, respectively. The genotypes with relatively high contents of GBS, SIN, GIB and GRA warrant detailed studies for future breeding programs since the hydrolysis products of these GSLs have several anti-cancer properties.

Cabbage is one of the most popular vegetables that is rich in sugars contributing to flavor and consumer acceptance; however, little information is available on the effect of genotypes and growing conditions on sugar accumulation. We assessed the seasonal variation in agronomic characteristics and free sugar content in cabbage (Brassica oleracea L. var. capitata L.) grown under open field conditions. Seventy-five cabbage genotypes were grown in the spring and autumn 2019, and their morphological characteristics and sugar concentrations were evaluated. Six cabbage types produced predominantly round-shaped heads (64 genotypes). Bright green and green were the dominant colors depending on the outer and inner leaves of the cabbage head. The most variable quantitative trait was head weight in both spring (36.9%) and autumn (49.2%). Glucose was the predominant sugar in most genotypes in both seasons. Mean glucose content in spring and autumn was 209.3 and 214.9 mg g-1 with 14.8% and 14.6% variation, respectively. Most genotypes produced higher fructose concentrations in fall than in spring. Sucrose levels showed the highest variation in both spring (36.0%) and autumn (60.5%), followed by fructose and glucose levels. Most agronomic parameters exhibited nonsignificant or negative correlations with sugar content, except the correlation of head height and width with glucose content. Fructose and glucose were positively correlated with total sugar content, while there was nonsignificant correlation with sucrose. Genotypes 160330 and 183701 produced comparably high and stable total sugar content in both seasons and can therefore be used as commercial breeding materials. We revealed a significant effect of genotype and season on cabbage agronomic characteristics and sugar content. [ABSTRACT FROM AUTHOR]