Development of DNA-markers of a trait of sunflower resistance to a broomrape (Orobanche cumana Wallr.) race G

Broomrape ( Orobanche cumana Wallr.) is an obligatory parasite which is able to decrease significantly sunflower yields. The race G is the most spread and virulence broomrape race in the Russian Federation. Cultivation of genetically resistance sunflower varieties and hybrids is the most ecologic and economically efficient method to control this parasite plant. Usage of DNA-markers when selecting the resistant plants increases significantly the effectiveness of a breeding process. To mark the sunflower resistance to broomrape race G, using bioinformative approaches, we developed new DNA-markers: four SCAR (sequence characterized amplified region) and ten SSR (simple sequence repeat). These markers were tested on 20 lines and hybrids of sunflower. Due to the results of this testing, all SSR- and two SCAR-markers were eliminated by steps. SCAR-marker RORS1 was characterized with the presence of an amplified DNA fragment with a length ≈ 168 bps and showed association with a trait of resistance, and SORS1 with a fragment length ≈ 322 bps had a relation with a susceptible phenotype. These markers composed a marker system for a multiplex PCR, which allowed distinguishing resistant and susceptible lines and hybrids, except a line VK678 and F1 hybrids developed using this line as parental one. To eliminate faults of the marker system, seven SCAR-markers analogous to SORS1 were created. Due to estimation result, we selected a marker SORS9 characterized with the presence an amplified DNA fragment with a length ≈ 217 bps in susceptible phenotypes. The new system of markers RORS1/SORS9 for a multiplex PCR was validated on 70 sunflower lines and hybrids. The susceptible lines and hybrids were characterized with amplification of only marker SORS9, resistant lines - only marker RORS1, and resistant hybrids - both markers. The developed marker system allowed distinguishing all susceptible lines and hybrids from the resistant sunflower genotypes.