Elite durum wheat genetic map and recombination rate variation in a multiparental connected design

Abstract

Genetic maps published for elite durum wheat (Triticum turgidum durum Desf.), were mainly related to Italian and North American pools. To provide additional information dedicated to durum elite pool, a recombinant inbred population (217 RILs) derived form 2 French commercial varieties (Ixos and Primadur), has been mapped with 529 loci (98 AFLPs, 67 SSRs, 1 ISBP and 363 DArTs). Genetic map spanned a total of 2,082 cM (5.7 cM/marker on average). Recombination rate variation over the genome was documented through the analysis of six segregating populations representing a total of 48 RILs × 6, issued from an half diallel design based on four elite lines—Neodur, Ixos, Lloyd and Primadur—including the 2 previous genitors. Each set of three genetically connected populations (48 RILs × 3) was used to build the consensus parental maps for each genitor. To construct the four consensus parental maps, marker ordering was determined on 217 RILs map which was an extended population of the most polymorphic cross (Ixos × Primadur). Sizeable, recombination rate variation has been observed between the four parental maps both at the marker pair scale and at the linkage group scale. Two of the parents, Lloyd and Primadur, had strong, opposite effects increasing and decreasing, respectively the recombination rate. Additional studies are proposed to increase our understanding of this variation, with the identification of environmental or genetic factors affecting recombination rate.