Identification of Downy Mildew Resistance Loci in Sunflower Germplasm

Abstract

Downy mildew caused by Plasmopara halstedii is one of the most economically important fungal diseases on sunflower (Helianthus annuus). To date, several downy mildew resistance genes called Pl genes have been reported on sunflower genetic map. Previous findings have confirmed that Iranian sunflower germplasms are harbouring Pl resistance genes that may be used to control downy mildew. In the current study, there were investigated the Pl5 and Pl16 downy mildew resistance genes in 51 inbred lines of Iranian sunflower, using PCR-based method. Fifteen differential lines carrying Pl5 and Pl16 downy mildew resistance genes were used as positive control. DNAs from 51 sunflower inbred lines were used in PCR reactions using primer pair RS1008 and Hap3 previously reported to serve as tightly linked to Pl16 and P5 loci, respectively. The PCR results confirmed the presence of two Pl16 and Pl5 bands with the size of about 280 and 1,580 bp, respectively, in differential lines. The results indicated that 1 inbred line out of 51 was found to carry Pl5 gene and 10 lines were found to carry Pl16 gene across the studied Iranian sunflower genotypes. These findings may be used to assist breeders for conservation and selection of downy mildew resistant sunflower genotypes.