Three Brassica species, namely, Brassica rapa, B. nigra, and B. oleracea are considered economically important as they are grown for human consumption and biogas production. Like other crops facing agricultural constraints, selective crossing or hybridization in cruciferous vegetables has helped farmers to improve them. This study conducted a comparative evaluation across and within the species through cytogenetic analysis to provide fresh insights into their chromosome structures and evolutionary relationships. A new karyomorphological parameter confirmed symmetric karyotypes in all the accessions, thereby allowing for the depiction of the ancestral chromosome karyotype. Several lines of B. rapa, B. nigra, and B. oleracea were subjected to physical mapping using a fluorescence in situ hybridization technique to elucidate the chromosomal distribution of the two types of rDNAs. The signal number and distribution of 18S rDNA across the metaphase chromosomes of B. rapa accessions did not vary as compared to 5S rDNA, which was also observed in several lines of B. nigra. In contrast, the number and distribution of 5S rDNA loci across the chromosomes in several lines of B. oleracea were found to be more conserved than those corresponding to the 18S rDNA. Overall, this study revealed the evolutionary dynamics of rDNA, which may play an important role in shaping the chromosome karyotypes of Brassica species.

Chrysanthemum morifolium Ramat. is one of the major flowering crop plants worldwide. However, domestic chrysanthemum markets have recently faced a downturn. To stimulate related industries, breeding technologies and efficient protection systems using molecular markers must be established. However, high cost and intensive efforts are required to develop useful molecular markers for the chrysanthemum as it is a polyploid crop with highly complex genome organization. Thus, the aim of this research was to develop expressed sequence tag-based simple sequence repeat (EST-SSR) markers, which are applicable to the chrysanthemum breeding program and cultivar protection, based on next-generation sequencing technology. From the RNAseq data of the standard chrysanthemum cultivars ‘Jungwoon’ and ‘Seinoisei,’ we identified 31,121 SSR loci and further retrieved 1,846 polymorphic SSRs. To test the marker efficiency of the 1,846 SSRs, we first chose 50 of the SSRs and designed primers by using the flanking sequences. It is noted that the nine EST_SSR markers show a single band-like amplicon, which can be exploited in various genetic studies. We proceeded to polymorphism tests for those SSRs with 56 chrysanthemum cultivars, confirming that the average polymorphism index content (PIC) was 0.69±0.058. Among those, we found that six SSRs were sufficient to specify the genetic identities of 55 chrysanthemum cultivars, which may be useful for protections of the related cultivars, as well as breeding programs, in the future.

Watermelon (Citrullus lanatus) is an economically important vegetable crop all over the world, which has functional compounds such as lycopene and citrulline. Gummy stem blight caused by Didymella bryoniae is one of the most devastative diseases in watermelon. Single nucleotide polymorphisms (SNPs), which are genetic variations occurring between individuals with respect to a single base, were often used to construct genetic linkage maps and develop molecular markers linked to a variety of horticultural traits and resistance to several diseases. In this study, we developed high-resolution melting (HRM) markers based on SNPs generated from NGS resequencing of two parents in watermelon. Plant materials were C. lanatus ‘920533’ (female and susceptible parent), C. amarus ‘PI 189225’ (male and resistant parent), and their F₁ and F₂ progenies. A total of 13.6 Gbp (‘920533’) and 13.1 Gbp (‘PI 189225’) of genomic sequences were obtained using NGS analysis. A total of 6.09 million SNPs between ‘920533’ and ‘PI 189225’ were detected, and 354,860 SNPs were identified as potential HRM primer sets. From these, a total of 330 primer sets for HRM analysis were designed. As a result, a total of 61 HRM markers that have polymorphic melting curves were developed. These HRM markers can be used for the construction of SNP-based linkage maps and for the analysis of quantitative trait loci (QTLs) related to gummy stem blight resistance.

This experiment was carried out to compare the morphological traits of 880 Korean soybean landraces from RDA genebank. Days to flowering were ranged from 51 to 104 days with an average of 74.4 days, days from flowering to maturity were ranged from 28 to 106 days with an average of 72.2 days, days from planting to maturity were ranged from 101 to 188 days with an average 146.6 days. Growth days were the shortest with 140.6 days in soybean landraces from Gangwon Province, and the longest with 152.8 days in those from Jeju Province. The 100 seed weight was ranged from 4.3 to 46.4 g with an average of 26.1 g, higher than other studies, relatively. The 100 seed weight was the lightest from Gyeongnam Province (22.7 g), and the heaviest from Chungnam Province (29.1 g). The highest percentage of seed coat color was black (52.4%), followed by yellow (28.5%). Landraces from Gyeongnam Province was the most yellow seed coat with 50.7%, seed coat color of those from Jeju was similar proportion in yellow (33.3%), green (25.9%) and black one (40.7%), and that from Gyeonggi was more green (28.8%) than yellow (16.7%). As a result of cotyledon color in 460 black seed was 59.7% with yellow, 40.1% with green. Three hundred fifty accessions of Korean soybean landraces were analyzed using 7 SSR markers. One hundred ten alleles were detected with a lowest 10 at the Satt307 and a highest 26 at the Satt173. The average polymorphism information content (PIC) was 0.71. Gene diversity was the highest in Jeju province while the lowest in Jeonnam.