13330
10.30848/PJB2025-3(14)
<p>
Evaluating rice blast resistance in Egyptian genotypes: a combined phenotypic and molecular approach</p>
Asmaa S. Nofal, Said S. Soliman, Tarik A. Ismail, Hany Wafa, Areej S. Jalal, Salha Mesfer Alshamrani, Diaa Abd El-Moneim, Wael F. Shehata, Wessam F. Felemban, Rahma Alshamrani and Abdallah A. Hassanin
<p>
Rice blast disease caused by the pathogen <em>Magnaporthe oryzae</em> is a destructive fungal disease of rice, causing significant yield losses and economic damage. Molecular screening and phenotypic assessment of blast resistance genes were conducted in five Egyptian rice genotypes: Sakha101, Sakha104, Orabi 4, Sakha101×Orabi 4, and Sakha104×Orabi 4. The severity and incidence of neck and leaf blast diseases were estimated using specific molecular markers. The highest neck and leaf blast incidence (54.44%) and (77.78%) were observed in Sakha 104 and Sakha101, respectively. Conversely, the lowest leaf and neck blast incidence (18.89% and 0%, respectively) was observed in Orabi 4. Leaf blast severity ranged from 48.09 % in Sakha104 to 10% in Orabi 4. The highest severity was recorded in Sakha 101 (38%), while neck blast severity was 0% at orabi4 and Sakha101×Orabi4. Five major rice blast resistance genes (<em>Pi-d2, Pi-z, Pi-9, Pi-37,</em> and <em>Pi-b</em>) were screened using molecular markers in the five studied genotypes. The results revealed that all genotypes were positive for the Pi-d2, Pi-z, and Pi-b markers except the absence of Pi-b marker in Sakha 104 genotype. All genotypes were negative for the Pi-9 and Pi-37 markers. The frequency of <strong>resistance genes (R genes)</strong> was 0% for Pi-9 and Pi-37 markers, 80% for Pi-b, and 100% for Pi-d2 and Pi-z. The current study concludes that rice leaf and neck blast diseases are more prevalent in the Sakha101 and Sakha104 genotypes <strong>compared to</strong> the Orabi4, Sakha101×Orabi4, and Sakha104×Orabi4 genotypes. These genotype's <strong>resistance genes hold promise as</strong> sources for breeding programs aiming to develop blast-resistant rice cultivars in Egypt.</p>
Published
2025
57
3
1005
1012