15 research outputs found
Variation in pathogenicity among single-oospore isolates of Sclerospora graminicola, the causal organism of downy mildew in pearl millet
Novas raças de Bremia lactucae, agente causador do mÃldio da alface, identificadas no estado de São Paulo
Rapid mapping of two genes for resistance to downy mildew from Lactuca serriola to existing clusters of resistance genes
Sources and genetic structure of a cluster of genes for resistance to three pathogens in lettuce
Identification of QTLs conferring resistance to downy mildew in legacy cultivars of lettuce
Many cultivars of lettuce (Lactuca sativa L.), the most popular leafy vegetable, are susceptible to downy mildew disease caused by Bremia lactucae. Cultivars Iceberg and Grand Rapids that were released in the 18(th) and 19(th) centuries, respectively, have high levels of quantitative resistance to downy mildew. We developed a population of recombinant inbred lines (RILs) originating from a cross between these two legacy cultivars, constructed a linkage map, and identified two QTLs for resistance on linkage groups 2 (qDM2.1) and 5 (qDM5.1) that determined resistance under field conditions in California and the Netherlands. The same QTLs determined delayed sporulation at the seedling stage in laboratory experiments. Alleles conferring elevated resistance at both QTLs originate from cultivar Iceberg. An additional QTL on linkage group 9 (qDM9.1) was detected through simultaneous analysis of all experiments with mixed-model approach. Alleles for elevated resistance at this locus originate from cultivar Grand Rapids