Comparative Molecular Cytogenetic Analysis of Ribosomal DNAs Distribution inBrassicaSpecies

Abstract

The genus Brassica in the mustard family comprises 38 species, which include economically important crops . Of these crops, many are valuable sources of vegetables (Masarirambi et al. 2020), oils (Sun 2017), feed and forage (Westwood and Mulcock 2012), and medicines (Saeidnia and Gohari 2012). Owing to their high market demand, several genera of Brassicaceae have been subjected to plant breeding, and considerable research, including the identification of agronomic traits, diversity analyses, and genetic mapping (Nishio 2014, Sharma et al. 2014, Velasco et al. 2017. Moreover, three diploid species, that is, Brassica rapa (2n = 2× = 20), Brassica nigra (2n = 2× = 16), and Brassica oleracea (2n = 2× = 18) are denoted as A, B and C genomes, respectively, in the triangle of U (U 1935). Based on their close relationships, interspecific hybridization has been effectively conducted among the Brassica diploids for the production of new species and the introgression of useful adaptive traits for targeted crop improvement (Dhaliwal et al. 2017, Elvis et al. 2020, Navabi et al. 2010. Furthermore, the progress in understanding the genome structures of Brassica species has been greatly underpinned by molecular cytogenetic studies (Chèvre et al. 2018, Hong et al. 2008.