Inheritance and molecular mapping of powdery mildew (Golovinomyces orontii) resistance gene(s) in sunfower (Helianthus annuus L.)

Abstract

Sources of resistance to powdery mildew incited by Golovinomyces orontii have been identifed in wild sunfowers and few exotic lines. The present investigation has been undertaken to study the inheritance of powdery mildew resistance and to map the quantitative trait loci (QTLs) governing resistance to powdery mildew in a multiple disease resistance line, TX16R (PI 642072). The inheritance was observed as a continuous distribution in a set of 264 F2 population and 93 recombinant inbred lines (RILs) of a cross between a highly susceptible accession PS 2023 and TX16R. Screening of the two population sets was done with 484 sunfower-specifc SSR primers of which 175 primers showed polymorphism between the parents. Based on the phenotyping and genotyping data, the linkage map was constructed with 93 RILs. The map spanned 1200 cM and included 64 markers distributed along the 17 sunfower chromosomes in the haploid set. Quantitative trait loci (QTL) analysis identifed three genomic regions for resistance to powdery mildew, two of which mapped on chromosome 10 and one on chromosome 5. This is the frst report on mapping of powdery mildew resistance in sunfower and paves the way in fne mapping and introgression of resistance for powdery mildew in sunfower through marker-assisted breeding