Genomics, mapping and marker assisted selection strategies for disease resistance

PANIEGO NB; BAZZALO ME; BULOS M; LIA VV; FUSARI CM; ALVAREZ D; ALTIERI E; RAMOS ML; GALELLA MT; KASPAR M; HEINZ RA; ESCANDE A; ZAMBELLI A; SALA C

Mar del Plata

Congreso; 18th International Sunflower Conference; 2012

ASAGIR, ISA

ABSTRACT- Biotic stress is considered one of the most important factors affecting yield all over the world. Insunflower downy mildew, black rust, Sclerotinia rot, Verticillum wilt and Alternaria leaf spot areconsidered the most important fungal diseases. In the last ten years, several attempts have been madethrough conventional breeding and molecular biological studies to dissect the bases for fungal resistanceto allow molecular assisted selection. The detection and genetic location of resistance gene candidates andQTL for complex diseases, together with the development of molecular markers, linkage maps andgenetic association studies have largely contributed to that purpose. There exists a vast array of gene/genecomplexes for disease resistance, tracing back to cultivated or wild sunflowers species. Linkage dragaround disease resistance genes (DRG), especially when the resistance comes from wild species, is one ofthe most limiting issues which may decrease yield potential. However, molecular tools as marker assistedselection (MAS) have greatly increased the efficiency of resistance selection to different diseases.- The detection of new downy mildew and black rust R genes, their close genomic location, theirarrangement in clusters and its implication in breeding strategies is discussed. Main results of associationmapping employed as a complementary tool of family mapping strategies for head rot resistance QTLlocation are presented. Stacking genes controlling the resistance to main Argentinean races of Verticilliumdahliae have been obtained for the first time. Pyramiding major quantitative trait loci (QTL) to head rotand Alternaria is presented as a relative simple way to increase the resistance level for these diseases.- The state of the art of the genomics of resistance and MAS in breeding processes for some of themain sunflower pathogens are reviewed, The collaborative work between public and private institutionshas largely contributed to the elucidation of the architecture of disease resistance in sunflower which willprovide many tools to build up durable and sustainable disease resistances in modern sunflower hybrids.