Mapping of the Waxy Bloom Gene in ‘Black Jewel’ in a Parental Linkage Map of ‘Black Jewel’ × ‘Glen Ample’ (Rubus) Interspecific Population

Abstract

Black and red raspberries (Rubus occidentalis L. and Rubus idaeus L.) are the prominent members of the genus Rubus (Rosaceae family). Breeding programs coupled with the low costs of high-throughput sequencing have led to a reservoir of data that have improved our understanding of various characteristics of Rubus and facilitated the mapping of different traits. Gene B controls the waxy bloom, a clearly visible epicuticular wax on canes. The potential effects of this trait on resistance/susceptibility to cane diseases in conjunction with other morphological factors are not fully studied. Previous studies suggested that gene H, which controls cane pubescence, is closely associated with gene B. Here, we used tunable genotyping-by-sequencing technology to identify the de novo SNPs of R. occidentalis and R. idaeus using an interspecific population that segregates for the waxy bloom phenotype. We created linkage maps of both species and mapped the identified SNPs to the seven chromosomes (Ro01–Ro07) of Rubus. Importantly, we report, for the first time, the mapping of gene B to chromosome 2 of R. occidentalis using a genetic map consisting of 443 markers spanning 479.76 cM. We observed the poor transferability of R. idaeus SSRs to R. occidentalis and discrepancies in their previously reported chromosome locations.