Rapid identification technology of resistance to rice sheath blight in seedling stage.

In order to establish a rapid identification technology of resistance to sheath blight (SB) in rice seedling stage,five cultivars with different resistance to SB were adopted in identification of seedling stage in artificial climate incubator or temperature-controlled greenhouse and the results were verified through an experiment at rice adult stage in field.The results showed that about 85% relative humidity was suitable for SB mycelium to develop infection structures and infect rice seedlings.The SB resistance levels among 5 cultivar seedlings differed significantly at 1% levels and could be divided into two groups,relatively susceptible (Lemont,Wuyujing 3) and relatively resistant (YSBR1,Jasmine 85,Teqing).The symptom severe degrees of seedlings at different leaf-age (4-leaf stage or 5-leaf stage) were significantly different and the average disease rating at 4-leaf stage was significantly higher than that of 5-leaf stage.The differences of resistance among different cultivars in greenhouse were less than that in the field,but the resistant-to-susceptible order among the cultivars were consistent with that in the field.Rapid identification technology of rice SB resistance in seedling stage could be used for screening resistance of rice germplasm on a large-scale scope or primary resistance identification.