title: Mapping and validation of QTLs for resistance to aphids and whiteflies in melon.
abstract: Aphis gossypii and Bemisia tabaci are severe hemipteran pests of melon crops and breeding for resistance to both insects is required to reduce pesticide use. Resistance was evaluated for its effect on behaviour and biotic potential of both hemipterans in a population of recombinant inbred lines (RILs) derived from the cross Védrantais x PI 161375. Insect variability was considered using two A. gossypii clones and two B. tabaci populations. Two additive QTLs affected the whiteflies. Four additive QTLs and two couples of epistatic QTLs affected the aphids. Amongst them, a major QTL affects both behaviour and biotic potential of A. gossypii and therefore a same R gene induces both antixenosis and antibiosis. This major QTL colocalizes with the Vat gene belonging to the NBS-LRR gene family. No loci affected both aphids and whiteflies contrary to what was observed for the Mi1.2 gene, a NBS-LRR gene in tomato. Original populations with different allelic compositions at QTLs affecting A. gossypii were built by one inter-crossing of RILs used for the mapping process. The genetic background was shown homogeneous between these populations what allowed validating QTLs and investigating the effect of allelic combinations at QTLs. Effects of QTLs were stronger than expected and some QTLs had a wider spectrum than expected. This strategy of validation appeared rapid and low cost.
authors.affiliation: Génétique et Amélioration des Fruits et Légumes, INRA, UR1052, B.P. 94 F-84143, Montfavet cedex, France. Nathalie.Boissot@avignon.inra.fr
authors.forename: Nathalie
authors.initials: N
authors.lastname: Boissot
authors.forename: Sophie
authors.initials: S
authors.lastname: Thomas
authors.forename: Nicolas
authors.initials: N
authors.lastname: Sauvion
authors.forename: Cécile
authors.initials: C
authors.lastname: Marchal
authors.forename: Claudie
authors.initials: C
authors.lastname: Pavis
authors.forename: Catherine
authors.initials: C
authors.lastname: Dogimont
mesh_terms: D000818:Animals; D001042:Aphids / Q000472:pathogenicity*; D002874:Chromosome Mapping; D018556:Crops, Agricultural / Q000235:genetics / Q000469:parasitology; D019662:Cucurbitaceae / Q000235:genetics / Q000469:parasitology; D005260:Female; D005819:Genetic Markers; D006430:Hemiptera / Q000472:pathogenicity*; D006790:Host-Parasite Interactions; D007113:Immunity, Innate / Q000235:genetics; D018551:Solanum lycopersicum / Q000235:genetics; D010572:Pest Control, Biological; D010935:Plant Diseases / Q000469:parasitology; D040641:Quantitative Trait Loci
chemical_list: D005819:Genetic Markers