Abstract
Rye stem rust caused by Puccinia graminis f. sp. secalis can be found in all European rye growing regions. When the summers are warm and dry, the disease can cause severe yield losses over large areas. To date only little research was done in Europe to trigger resistance breeding. To our knowledge, all varieties currently registered in Germany are susceptible. In this study, three biparental populations of inbred lines and one testcross population developed for mapping resistance were investigated. Over 2 years, 68–70 genotypes per population were tested, each in three locations. Combining the phenotypic data with genotyping results of a custom 10k Infinium iSelect single nucleotide polymorphism (SNP) array, we identified both quantitatively inherited adult plant resistance and monogenic all-stage resistance. A single resistance gene, tentatively named Pgs1, located at the distal end of chromosome 7R, could be identified in two independently developed populations. With high probability, it is closely linked to a nucleotide-binding leucine-rich repeat (NB-LRR) resistance gene homolog. A marker for a competitive allele-specific polymerase chain reaction (KASP) genotyping assay was designed that could explain 73 and 97% of the genetic variance in each of both populations, respectively. Additional investigation of naturally occurring rye leaf rust (caused by Puccinia recondita ROEBERGE) revealed a gene complex on chromosome 7R. The gene Pgs1 and further identified quantitative trait loci (QTL) have high potential to be used for breeding stem rust resistant rye.
Highlights
Rye stem rust caused by Puccinia graminis f. sp. secalis ERIKSS. & HENNING can be a severe threat for rye (Secale cereale L.) in epidemic years
Stem Rust Resistance Of the three repeated ratings conducted in each environment most often the final rating had the highest repeatability (0.45– 0.99) and was, used in the one-stage model
We found a single resistance gene segregating that caused most of the genetic variance in P2 and P4 and was active in seedling stage
Summary
Rye stem rust caused by Puccinia graminis f. sp. secalis ERIKSS. & HENNING can be a severe threat for rye (Secale cereale L.) in epidemic years. Rye stem rust caused by Puccinia graminis f. Infected plants show spore-filled cracks all over the stems, and if the infection level is high, even on leaves and heads. Yield losses due to rye stem rust are reported from Northeastern Europe, the largest growing region worldwide, but the disease was reported to occur in Brazil (Roelfs, 1985) and South Africa (Boshoff et al, 2019). In contrast to population breeding, hybrid breeding is based on the combination of inbred lines carrying a self-fertility gene. To select for grain yield and other heterotic traits, testcrosses are produced by crossing inbred lines to single-cross testers of the opposite heterotic group and by evaluating their testcross performance in the year after
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
