Powdery mildew (Blumeria graminis f. sp. tritici) significantly affects wheat yield and flour quality. Plant resistance to powdery mildew has been investigated for decades, and numerous resistance genes and quantitative trait loci (QTLs) for molecular markers have been discovered. In Korea, powdery mildew occurs initially in spring, due to frequent rain and low temperatures, becoming severe during the harvest season. In Korea, systematic monitoring and quantitative and qualitative impact assessments of powdery mildew outbreaks have never been conducted properly. Herein, the lifecycle of powdery mildew, resistance genes, QTLs, and selection markers in wheat were examined to elucidate powdery mildew resistance, develop resistant varieties, and genetic markers suitable for the domestic environment.

A new malting barley variety, ‘Baegrok’, was developed in 2016 at the National Institute of Crop Science, RDA: Rural development administration by crossing the high-yield ‘Milyang130’ variety with ‘Myoginijo’, which has lodging tolerance and resistance to barley yellow mosaic virus (BaYMV). ‘Baegrok’ is suitable for use in brewing, similar to ‘Hopum’, and has resistance to powdery mildew and tolerance to lodging. From 2014 to 2016, regional yield trials were conducted in four different regions, with ‘Baegrok’ as a breeding line of ‘Iksan176’. The heading dates of ‘Baegrok’ in paddy and upland fields were April 6 and April 11, respectively, 2 days earlier than those of ‘Hopum’. Maturing dates of ‘Baegrok’ in paddy and upland fields were May 16 and May 21, respectively, similar to those of ‘Hopum’. The yield potential of ‘Baegrok’ was approximately 14% and 6% higher than that of ‘Hopum’ in upland and paddy fields. ‘Baegrok’ had a shorter culm length than ‘Hopum’ showing tolerance to lodging. Screening for powdery mildew resistance in the greenhouse showed that ‘Baegrok’ had resistance to powdery mildew, unlike ‘Hopum’ which was susceptible. It also is suitable for use in brewing, similar to Hopum. ‘Baegrok’ showed good grain quality in terms of β-glucan content (3.4%), starch (61.0%), and husk rate (12.7%). Regarding malt quality, ‘Baegrok’ exhibited 75.1% acrospire length, 70.8% friability, 4.4% soluble protein, and 345.8 WK (Windisch-Kolbach) diastatic power, superior to the malt quality of ‘Hopum’. Thus, ‘Baegrok’ is resistant to powdery mildew, tolerant to lodging, and more suitable for brewing. (Registration No. 8399)

In this study, genotype analysis was conducted using the Fluidigm system with 13 SNP markers related to anthracnose, powdery mildew, phytophthora root rot, cucumber mosaic virus (CMV), potyvirus, and tobacco mosaic virus (TMV) resistance. A total of 25,350 data points were obtained, 8.2% of which indicated resistance genotypes. Resources having perfect resistance genotype to each disease-related molecular marker set were 58 accessions for anthracnose, 57 for powdery mildew, 246 for phytophthora root rot, and 765 for CMV. There was no resource having a perfect resistance genotype of all three potyvirus-related molecular SNP markers including pvr1, pvr2 (123457), and pvr2 (689). Thirty-seven accessions for pvr1, 349 accessions for pvr2 (123457), and 23 accessions for pvr2 (689) were identified as resources with resistance genotype. No resource with the TMV-resistance genotype was found in this study. The resources with complex resistance genotypes of anthracnose and powdery mildew were 55 accessions, and they were mainly Capsicum baccatum. Among these, seven accessions had a three-disease combined resistance genotype with phytophthora root rot. Thirty-six accessions, 16 accessions, and nine accessions each had resistance genotypes of the three potyvirus-related markers. These resources also had CMV and phytophthora root rot resistance genotypes, and they were mainly Capsicum chinense. The statistical analysis considering the evaluated resistance genotypes, revealed that the anthracnose resistance genotype showed a tendency to be linked with powdery mildew resistance genotype. The potyvirus-related marker pvr1 was positively correlated with Phytophthora root rot markers.