Genetics, genomics and breeding in Rosa species

Rose is one of the most important ornamental crops of the family Rosaceae. It is a complex crop having a patchy genome with different ploidies (2× to 10×), majorly tetraploid. With advancements in technologies, Rosa species are also being explored to understand the genetic, genomics, and molecular mechanisms behind variations of the traits. Whole-genome sequence information for the two Rosa spp. viz R. chinensis and R multiflora are available in three different studies. High-density SNP chip (68 K) further complements the molecular studies in Rose. A number of genes/QTLs have been identified and well-characterised for important traits using high-density genetic maps. Apart from genetics, epigenetics including DNA methylations and microRNAs are also being explored and found to be associated with diverse phenotypes. Despite substantial molecular tools and information, rose is still bred through conventional methods, perhaps due to its complex genome and ploidy. Thus in this review, an attempt has been made to compile all the existing molecular, genetics and genomics facts in rose and its possible utilisation in rose improvement programmes. We also discussed the forth coming prospects that can be found very potential for rose breeding.