## 4 Discussion  
The development of new genomic tools can facilitate advances in breeding technology, leading to greatly improved crop varieties that can, in turn, enhance global food security under the challenges of climate change [32]. Biotic stresses are one of the many consequences arising from changes in climate [33]. Stripe rust is considered one of the most important biotic stresses that can negatively affect wheat production worldwide [34]. Hence, it is important to screen wheat germplasm in response to the different virulence types of _Pst_ present in different regions of the world [35]. In this study, we evaluated a panel of unique durum wheat landraces, predominating from Iran, to two races of _Pst_ at the seedling stage in the glasshouse. We observed a high level of phenotypic variation among the tested accessions (Table 1), a result consistent with previous reports on the response of durum wheat germplasm to stripe rust [12; 23; 36; 37; 38]. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Chromosome**} & \multirow{2}{*}{**Numbers of SNPs**} & \multirow{2}{*}{**Length (cM)**} & \multicolumn{6}{c}{* **Average Linkage Disequilibrium (\(r^{2}\)) between Pair of Markers**} \\ \cline{4-9}  & & & **D \textless{} 5 cM** & **D = 5–10 cM** & **D = 10–20 cM** & **D = 20–50 cM** & **D > 50 cM** \\ \hline
1A & 181 & 106 & 0.214 & 0.094 & 0.069 & 0.048 & 0.035 \\
1B & 249 & 101.5 & 0.127 & 0.044 & 0.043 & 0.039 & 0.034 \\
2A & 206 & 119.7 & 0.147 & 0.041 & 0.092 & 0.037 & 0.032 \\
2B & 391 & 144.2 & 0.149 & 0.083 & 0.065 & 0.043 & 0.041 \\
3A & 184 & 163.4 & 0.264 & 0.099 & 0.051 & 0.052 & 0.047 \\
3B & 340 & 137 & 0.139 & 0.052 & 0.055 & 0.038 & 0.035 \\
4A & 168 & 161.8 & 0.238 & 0.029 & 0.33 & 0.023 & 0.039 \\
4B & 150 & 107 & 0.147 & 0.044 & 0.036 & 0.044 & 0.048 \\
5A & 193 & 106.7 & 0.217 & 0.077 & 0.049 & 0.037 & 0.061 \\
5B & 270 & 179.6 & 0.25 & 0.062 & 0.038 & 0.033 & 0.031 \\
6A & 240 & 120.2 & 0.317 & 0.047 & 0.153 & 0.04 & 0.034 \\
6B & 231 & 110.4 & 0.127 & 0.046 & 0.041 & 0.038 & 0.039 \\
7A & 251 & 165.9 & 0.149 & 0.043 & 0.043 & 0.031 & 0.04 \\
7B & 267 & 142 & 0.145 & 0.049 & 0.042 & 0.041 & 0.032 \\ \hline \hline \end{tabular}  
* The data presented in this table are based on LD analysis for a subset of genotyping data (3232 SNPs) with a known position on chromosomes.  
\end{table} 
Table 2: Average linkage disequilibrium (\(r^{2}\)) at different marker distances for 139 durum wheat accessions. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Trait** & **Marker** & **Position** & **Chr.** & **Marker** & **Position** & **Chr.** & **Marker** & **Position** & **Chr.** \\ \hline Pstv-37 & 115 & 6A & IAC8074 & 97 & 1B & wsnp\_Ex\_c2617\_486441 & 61 & 4A \\ Pstv-40 & 115 & 6A & IAC8074 & 97 & 1B & wsnp\_Ex\_c2617\_4864441 & 61 & 4A \\ Pstv-37 & 64 & 2B & IACX8294 & 116 & 7B & wsnp\_Ex\_c2617\_4864955 & 61 & 4A \\ Pstv-40 & 63 & 1A & IACV9290 & 97 & 1B & wsnp\_Ex\_c54395\_57291841 & 61 & 4A \\ Pstv-40 & 108 & 5A & Kukri\_c93635\_290 & 61 & 4A & wsnp\_Ex\_c6044\_1090220 & 61 & 4A \\ Pstv-40 & 63 & 1A & IAC875\_c5556\_328 & 45 & 1B & wsnp\_Ex\_c7002\_12063325 & 115 & 6A \\ Pstv-40 & 63 & 1A & Tdurum\_contig12525\_769 & 116 & 7B & wsnp\_Ex\_c7002\_12063380 & 115 & 6A \\ Pstv-40 & 63 & 1A & Tdurum\_contig12525\_769 & 116 & 7B & wsnp\_Ex\_c7002\_12063380 & 115 & 6A \\ Pstv-40 & 64 & 4A & Tdurum\_contig44173\_5725 & 55 & 6B & wsnp\_Ex\_c7550\_12907422 & 61 & 4A \\ Pstv-37 & 115 & 6A & Tdurum\_contig47269\_904 & 55 & 6B & wsnp\_Ex\_c831\_1625061 & 9 & 5B \\ Pstv-40 & 140 & 7B & Tdurum\_contig7981\_70 & 55 & 6B & wsnp\_Ex\_c652254555 & 55 & 6B \\ Pstv-37 & & 97 & 1B & wsnp\_Ex\_c12818\_20334501 & 61 & 4A & wsnp\_Ex\_c3081\_40208899 & 61 & 4A \\ Pstv-40 & 97 & 1B & & 61 & 4A & 61 & 4A \\ \hline \hline \end{tabular}  
* The data presented in this table are based on LD analysis for a subset of genotyping data (3232 SNPs) with a known position on chromosomes.  
\end{table}