الفهرس 
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Abstract
This investigation was carried out at Rice Research and Training Center (RRTC), Sakha, Kafr El-Sheikh, Egypt, This study aimed at identifying blast physiological races and the in-country geographical distribution of the common races of the pathogen, evaluating some commercial Egyptian rice cultivars and some promising lines against blast disease. Also, the study considered the identification of effective rice blast resistant genes in 14 Egyptian rice genotypes using specific DNA markers and marker assisted selection (MAS) program.
- One hundred and thirty two of P. grisea isolates were collected from rice-cultivating governorates in Egypt. IH race group was the most common race, followed by IC and IF groups, While IG, ID and IE were the minor race groups. The promising line GZ 9057-6-1-3-2 revealed the highest level of resistance against most isolates tested followed by Giza 178. On the other hand, the susceptible rice cultivars, Sakha 101 and The promising line GZ9461-4-2-1-2, were infected with the most tested isolates. Pi-z-5 gene found in IRBLz5-CA and IRBLz5-CA (R) lines scored the highest effective gene of blast resistance. This gene was followed by pita-2 gene, found in the monogenic line IRBLta2-Re. On the other hand, Pia gene found in IRBLa-A and IRBLa-C lines was the lowest effective resistant gene against the tested isolates.
- Some blast resistance genes were identified in 14 genotypes i.e., Giza 177, Giza 178, Sakha 101, Sakha 102, Sakha 103, Sakha 104, Sakha 105, Sakha 106, Giza 182, GZ9057-6-1-3-2, GZ9523-2-1-1-1, GZ9461-4-2-1-2, GZ6296-12-1-2-1-1 and hybrid 1, by using specific DNA and SSR markers. The tested genotypes were found to contain two blast resistance genes (Sakha 104) and 15 blast resistance genes (Giza 178).