Brassica juncea, a member of the Brassicaceae family commonly referred to as mustard, is an allotetraploid (AABB, 2n=36) resulting from interspecific hybridization between Brassica rapa (AA, 2n=20) and Brassica nigra (BB, 2n=16). In this study, microspores were cultured using F₁ hybrids between two selected B. juncea double haploid (DH) lines with high anthocyanin and glucosinolate contents in the maternal versus leafy paternity. The results of the microspore culture showed that the total number of cultured buds, obtained embryos, and embryos per bud were 2,010, 15,526, and 7.62, respectively. Colchicine was used to induce the amphidiploids (AABB). We found that 149 of the 218 regenerated plants (68.3%) were amphidoploid. Among them, 117 individuals underwent ripening and seed harvesting and were used for subsequent phenotype analysis. Leaf color, length, and other agricultural traits exhibited various patterns owing to the recombination of the parental allele. The glucosinolate (GSL) content ranged from a maximum of 29.27 μmol/g dry weight to a minimum of 6.39 μmol/g dry weight, exceeding the range of parental value. The composition of GSL was mainly aliphatic, with sinigrin accounting for approximately 89% of the total aliphatic GSL content. These DH lines and their respective unique phenotypic traits are crucial for crop breeding and are valuable resources for advancing functional genomics and developing molecular markers in B. juncea.

Prunus persica “Mihong” cultivar is a domesticated white peach that was generated from the crossing between “Yumyeong” and “Chiyomaru” cultivars in the Republic of Korea in 1995. We launched “Mihong” genome sequencing in 2018 and “Mihong” reached to 200 scaffold and 241 Mb sequences using long-read sequencing and Hi-C technology. F₁ populations of ”Kawanakajima Hakuto,” “Mihong,” “Changhowon Hwangdo,” and “Yumi” were developed in NIHHS. These four cultivars were sequenced and assembled using the SOAPdenovo version 2.04. First, we surveyed the SSRs in “Mihong” assembly sequences and extracted the ±300 bp flanking sequences containing SSRs. Second, the assembly sequences of three cultivars were aligned and mapped against “Mihong” ±300 bp flanking sequences using BLASTn (version 2.2.29+). We anticipated the differential length in SSRs among the four cultivars. We sorted the primers with a standard deviation over 4.5 (STEV > 4.5) among the four cultivars. In addition, we surveyed the primers having difference in over 10 bp with “Kawanakajima Hakuto” and “Mihong” for polymorphic markers in the mapping population. All primer pairs were designed to generate amplicons of 150-200 bp in coating SSR regions using primer3 (version 3-2.2.3). We selected 260 SSR markers with a physical distance of average per 1 Mb. These SSR markers accounted for 74% polymorphism in the four genotypes. Finally, a F₁ population of “Kawanakajima Hakuto” and “Mihong” covered 884.5 cM with 465 SNPs and 86 SSRs and this genetic map matched correctly to the HI-C pseudomolecule of P. persica.