EVALUATION OF CERTAIN EGYPTIAN RICE CULTIVARS TO BLAST DISEASE INCIDENCE DURING FOURTEEN YEARS IN EGYPT. | ||||
| Journal of Plant Production | ||||
| Article 11, Volume 33, Issue 4, April 2008, Page 2643-2657 PDF (654.36 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jpp.2008.164904 | ||||
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| Authors | ||||
| M. R. Sehly1; S. M. El-Wahsh1; M. M. El-Malky2; E. A. S. Badr1; R. A. S. El-Shafey2; I. R. Aidy2 | ||||
| 1Rice Pathol. Dept., Plant Pathol. Res., Institute, Agric. Res. Center, | ||||
| 2Rice Dept., Field Crops Res. Institute, Agric. Res. Center, Giza, Egypt. | ||||
| Abstract | ||||
| The study aimed to evaluate certain commercial Egyptian rice cultivars in both seedling and adult stages to blast disease, identify rice blast hot spots at different rice governorates, and identify effective rice blast resistance genes and common physiological races of Pyricularia grisea under field conditions during 1994 to 2007 seasons. Fourteen Egyptian rice cultivars were tested during the period of study. In addition, ten Japanese differential varieties and two international differential varieties evaluated at three locations i.e. Sakha, Gemmiza and Zarzora were included and tested under natural infection at blast nursery tests. As for field resistance, the cultivars Giza 171, Giza 172, Giza 176, Giza 159 and Reiho were susceptible during such period, hawever, Reiho cultivar escaped from the disease in some locations in 2005 season. Also, the cultivars Sakha 101 and Sakha 104 were resistant through 1994 up to 2002, except through 1997 up to 1999, Sakha 104 was infected in one or all locations with 2-4 blast score . Starting from 2003 and 2004, the resistance was broken down in some locations and the cultivars were completely susceptible in 2005 up to 2007 seasons. Giza 181 was infected in some locations in 2004 up to 2007. While, the cultivars Giza 175, Giza 177, Giza 178, Giza 182, Sakha 102 and Sakha 103 achieved complete resistance. On the other hand, these cultivars were transplanted at different locations (multi-location test) (18-22 locations yearly) and distributed on demonstration farmers' fields at six rice governorates starting from 1996 up to 2007 rice growing seasons. The results showed that Giza 171, Giza 159, Giza 176 and Reiho were susceptible in most of tested locations. While, Giza 181, Giza 177, Giza 178, Sakha 102, Giza 182 and Sakha 103 were completely resistant in all tested locations during this period. On the other hand, Sakha 101 and Sakha 104 were resistant up to 2003 and became susceptible in 15% of the tested locations starting from 2004 season. The level of susceptibility increased to 47.6, 85.7 and 72.2% in 2005; 2006 and 2007 seasons, respectively for Sakha 101, and increased to 28.6, 66.7 and 44.4% for Sakha 104 in 2005, 2006 and 2007 seasons, respectively. The resistant genes (Pi-a and Pi-ks ) exhibited low levels with 20 and 31 %, respectively, while higher levels of Pi-b, Pi-k and Pi-m genes with 90, 85 and 80 % respectively were found during 1994- 1996 seasons. While during 1997 up to 2000, higher levels of resistant genes Pi-z and pi-k with 95.6 and 93.4% but Pi-a and Pi-ta genes showed lower levels of resistance with 14.3 and 21.1%, respectively. In the last period (2001-2004) Pi-a and Pi-ta2 genes showed low level of resistance with 15 and 25 %. The rest genes showed high levels and ranged from 60-95%. Concerning greenhouse tests, the results showed that IC race group was common race followed by IB and IG groups while IE, IF, IH and II were rare, However, IH and IG groups were the common races during 1997 up to 2000 period. The third and fourth periods (2001 up to 2006) IG group was the common one and it was specific on Sakha 101 rice cultivar and responsible for its breakdown, followed by IB group which include IB-45 race as a specific race for Sakha 104 and also responsible for its breakdown. | ||||
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