ISHS Acta Horticulturae 510: VII Eucarpia Meeting on Cucurbit Genetics and Breeding
THE SPANISH MELON GENOME PROJECT: CONSTRUCTION OF A SATURATED GENETIC MAP |
| Authors: | M. Oliver, J. Garcia-Mas, M. Morales, R. Dolcet-Sanjuan, M. Vicente, H. Gómez, H. Leeuwen, A. Monfort, P. Puigdomenech, P. Arús |
| Keywords: | melon, genetic map, nsv, resistance gene homologues |
| Abstract:
A genetic map with 385 molecular markers (228 RFLPs, 82 AFLPs, 40 RAPDs, 29 SSRs, 5 inter-SSRs and 1 SCAR), one morphological trait (number of carpels), and one disease-resistance gene has been constructed. A cross between the Korean accession PI 161375 and the Spanish ‘Piñonet Piel de Sapo’ was made to obtain the F2 mapping population. RFLPs were obtained from genomic and cDNA melon libraries, also including 20 Arabidopsis ESTs, 13 known genes of Cucumis, and three resistance-gene homologues. All markers were distributed in 12 linkage groups covering a total genetic distance of 1185 cM with an average map density of 3.1 cM/marker. This map contains several common markers (RFLPs and SSRs) with other melon and cucumber genetic maps. The F2 of this cross segregated for two disease resistance genes, nsv and Vat, and we have also derived from it 99 double haploid lines (DHLs). Closely linked markers for the nsv gene have been obtained using a bulked segregant analysis approach. These markers will be used in marker assisted breeding projects and for map-based cloning of the resistance gene. We have cloned four different families of melon resistance gene homologues containing the nucleotide binding site (NBS) motif using a PCR approach based on degenerate primers designed from two conserved regions of known disease resistance genes. Three of these homologues have been placed on the genetic map. One of them maps to the distal part of linkage group G7 and its homologous position in another melon genetic map contains the disease resistance gene Fom-I against Fusarium oxysporum f. sp. melonis races 0 and 2. | |
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