Blast resistance of space-induced variants derived from rice cultivar Hanghui 7

To screen the resistance lines to rice blast, the blast resistance of SP3 and SP4 progenies derived from rice variety Hanghui 7 were evaluated after satellite flight, and the genomic DNA polymorphism of the resistant variants selected from SP3 was compared with the wild type by microsatellite markers. The results indicated that the SP3 Variant line H24, which was selected from the 250 space-induced lines ( SP3) with excellent agronomic and economical characters, showed resistance segregation (119R : 108S) against blast isolate GD3286. It was demonstrated that the resistance of H24 might be controlled by two dominant and complementary resistance genes. The resistance of H24 was still segregated in SP4, but the resistance spectrum of H24 was 84. 4% in SP5, much higher than the wild type, 40. 6%, and H24 especially showed resistant against some blast isolates of broad pathogenic spectrum or specialized pathogenicity; further more, the DNA polymorphism wasn't detected between H24 and its wild type by 229 SSR (simple sequence repeat) markers covering the rice genome equally. (authors)