Construction of an intraspecific integrated linkage map of pepper using molecular markers and doubled-haploid progenies.

An integrated molecular linkage map of pepper (Capsicum annuum L.), including mainly RFLP and RAPD markers, has been constructed by alignment of three intraspecific linkage maps generated by segregating doubled-haploid progenies. A total of 85 markers covered approximately 820 cM in 14 linkage groups. Four linkage groups were assigned to 4 chromosomes. Two new genes of agronomic interest were located: L controlling hypersensitive resistance to TMV and up controlling the erect habit of the fruits. The C gene controlling the fruit pungency was more precisely located. This map is estimated to represent from 36 to 59% of the total pepper genome. An examination of segregation data has revealed several genomic regions with aberrant segregation ratios often favouring the agronomic big-fruited parents, particularly in crosses involving the exotic parent CM334, suggesting that these genome regions are subjected to selection during the process of doubled-haploid production. The suitability of doubled-haploid progenies for mapping projects and the differences observed between this intraspecific integrated map with earlier published interspecific pepper maps are discussed.