Abstract :
Experiments were carried out at Rice Research and Training Center during 2009 to 2012 growing seasons. This study aimed at evaluation of some commercial Egyptian rice cultivars and some promising lines against blast disease, identification of effective rice blast resistant genes, and distribution of physiological races and common races of Pyricularia grisea. One hundred and thirty two of P. grisea isolates were collected from rice-cultivating governorates in Egypt, namely Kafr ELSheikh (36 isolates), Gharbia (48 isolates), Dakahlia (18 isolates), Sharkia (12 isolates), Damietta (6 isolates) and Beheira (12 isolates). IH race group was the most common race (47.69%), followed by IC (26.58%) and IF (12.15%) groups, While IG,ID and IE (6.06, 6.04 and 1.49%, respectively) were the minor race groups during this study period. The promising line GZ 9057-6-1-3-2 revealed the highest level of resistance against most isolates tested (98.48%) followed by Giza 178 and GZ 9523- 2-1-1-1 (96.22% for each). On the other hand, the susceptible rice cultivars, Sakha 101 and Sakha104, were infected with the most tested isolates (25.76 and 61.36 % resistance, respectively). Pi-z-^5 gene found in IRBLz5-CA and IRBLz5-CA (R) lines scored the highest effective gene of blast resistance (97.76 and 95.50%,respectively). This gene was followed by pita-^2 gene, found in the monogenic line IRBLta2-Re (91.70%). On the other hand, Pia gene found in IRBLa-A and IRBLa-C lines was the lowest effective resistant gene with zero efficacy against the tested isolates. The highest percentage of race groups from the total identified isolates were obtained from Gharbia and Kafr El-Sheikh governorates (36.53 and 27.27%, respectively). On other hand, Damietta governorate had the lowest percentage of race groups (4.56% from the total identified races).
Keywords :
Rice , blast Pyricularia grisea , resistance gene , physiological races , monogenic lines
