The gene Yr5 in wheat has generally been known to confer resistance to Puccinia striiformis f. sp. tritici races worldwide. However, a few reports indicated that some isolates of the stripe rust pathogen were virulent on the wheat genotypes with Yr5 in India, Australia, and China (Nagarajan 1986; Wellings and McIntosh 1990; Zhang et al. 2020). In April 2020, a stripe rust infection was observed on Triticum spelta 'Album' (TSA), the Yr5 donor, provided by Turkey Seed Gene Bank in a wheat breeding field at the experimental station of Akdeniz University in the Antalya province of Turkey. The sample was tested on the seedlings of the Yr single-gene lines in the Avocet S (AvS) background including Yr5 near-isogenic line (AvSYr5NIL), TSA, and susceptible bread wheat variety 'Morocco' according to the procedure reported by Wan et al. (2014), and found to be highly virulent on Morocco with infection type (IT) 9 and virulent on AvSYr5NIL and TSA with IT 7. To confirm this novel finding, single-pustule isolates derived from this sample were obtained from TSA and re-tested on the differentials and TSA. The Yr5-virulent isolate yielded similar infection types on these plants further verifying previous results. The single-pustule isolates were determined to be avirulent (Avr) (IT 0 to 6) on AvSYr1NIL, AvSYr8NIL, AvSYr9NIL, AvSYr10NIL, AvSYr32NIL, and AvSYr43NIL and virulent (Vr) (IT 7 to 9) on AvSYr5NIL, AvSYr6NIL, AvSYr7NIL, AvSYr17NIL, AvSYr24NIL, AvSYr27NIL, AvSYr44NIL, AvSYrSpNIL, and TSA. The isolates were identified as a new race and temporarily named TRVR20-5 based on its Avr/Vr pattern. Furthermore, to confirm the presence of Yr5, the genomic DNA of fresh leaves of AvSYr5NIL and TSA used in the virulence testing were isolated using NucleoSpin Plant II (Macherey-Nagel, Germany) according to the manufacturer's procedure. The genomic DNA samples were amplified with the primers STS-7 (5'-GTACAATTCACCTAGAGT-3') and STS-8 (5'-GCAAGTTTTCTCCCTATT-3') (Chen et al. 2003) using a thermal cycler (T-100, BioRad, USA), and the resulting PCR products were digested with DpnII and visualized on an agarose gel. AvSYr5NIL and TSA had the fragment linked to the resistance allele (308 bp) whereas AvS and Morocco had the fragment linked to the susceptible allele (181 bp). Thus, both wheat genotypes were confirmed to carry Yr5, and the new Pst race virulent to Yr5 was confirmed. To the best of our knowledge, this is the first report of a Pst race virulent to Yr5 in Turkey, where stripe rust epidemics have occured in 2 out of every 5 years with 1-5% crop losses in over 25% of the wheat growing areas (Chen 2020). In a nutshell, monitoring the Pst races virulent to Yr5 with a potential to cause devastating epidemics worldwide is crucial due to the fact that international wheat breeding programs have been using Yr5 to develop wheat cultivars with resistance to stripe rust.

Turkey is one of the important gene centers for many crop species. In this research, some ancient wheats such as tetraploid and diploid hulled wheats together with hexaploid tir wheats (Triticum aestivum ssp. leucospermum Korn.) landraces mainly adapted to harsh winter conditions of Eastern Anatolian region of Turkey were characterized at agro-morphological and molecular level. Totally 50 hulled wheat population from Kastamonu, Konya and Kayseri provinces and 15 tir wheats from Kars provinces of Turkey were in-situ collected for characterization in 2013. Some quantitative and qualitative traits of each population were determined. Twenty three hulled wheat population collected from Kastamonu province were distinguished into nine emmer and 14 einkorn wheats at morphological level. Additionally, Konya, Kayseri and Kars population were characterized as einkorn, emmer and tir wheat, respectively. Among the evaluated traits, protein ratios of hulled wheats were strikingly higher than registered cultivars. All the populations were also examined by molecular level by using fluorescently labelled 11 polymorphic SSRs primers. The primers exhibited 104 bands, ranging from 6 to 16 with a mean value 9.45 per loci. The clustering analysis separated the germplasm into two clusters which were also divided into two subclusters based on genetic similarity coefficient. Sixty-five population and five checks were analyzed to estimate mean number of alleles (N), expected and observed heterozygoties (He and Ho), polymorphism information content (PIC), Wright fix index (F), genetic deviation from Hardy-Weinberg expectation (Fit-Fis) and genetic variation (Fst) were determined as 9.45, 0.71, 0.07, 0.67, 0.90, 0.39, 0.87 and 0.39, respectively. A clear genetic deviation from Hardy – Weinberg expectation was observed among population in particular. These results showed considerable genetic variation among landraces rather than within population. These molecular information has revealed genetically diverse einkorn, emmer wheat and tir wheat population could be used as parents for further breeding studies in both Turkey and abroad. Furthermore, the molecular analysis has also generally discriminated the germplasm into ploidy level.

Stripe rust, caused by Puccinia striiformis f. sp. tritici, is a devastating disease of wheat in Turkey and worldwide. This pathogen can overcome known resistance genes and negatively affect the wheat production. The objectives of this study were to determine the virulence patterns of wheat stripe rust isolates collected from the coastal areas (Aegean and Mediterranean regions) of Turkey, and to examine the genetic diversity of the pathogen populations by simple sequence repeat (SSR) marker analysis. The majority of the isolates collected were virulent at various frequencies on the resistance genes Yr1 (50%), Yr6 (100%), Yr7 (78%), Yr8 (50%), Yr9 (84%), Yr10 (25%), Yr17 (38%), Yr24 (22%), Yr27 (31%), Yr32 (22%), Yr43 (47%), Yr44 (6%), YrSp (41%), YrTr1 (6%), and avirulent on Yr5 and Yr15. Based on the analysis of virulence, all isolates were determined as 25 races and clustered into six virulence groups (VGs). In contrast, the isolates clustered into four molecular groups (MGs) based on genotypic data. All four MGs were found in Aegean region of Turkey, while only three MGs (MG1, MG2 and MG3) were found in the Mediterranean region of the country. Additionally, analysis of molecular variance indicated that 80.9% of genetic variation was found within regions and 19.1% was found between the regions. The results suggest that interregional migration of the pathogen was high. The data can be helpful for the management of stripe rust and understanding the population structure and migration of Pst in Turkey.