Screening Of Resistance Resources And Quantitative Trait Loci Mapping Of Resistance To BandedLeaf And Sheath Blight In Maize

It is because Banded Leaf and Sheath Blight (BLSB) is one of the most important diseases of maize in China,especially in the southwest ,the resources of resistance to BLSB are insufficient in our country, and hereditary variation regularity of resistance to BLSB is not very clear. Therefore, we had made systematic researches on screening of resistance resources and the modern molecular locating method such as QTLs'. The main results are followed.(1) Forty five maize inbred lines were evaluated for reaction to BLSB with artificial inoculation during a period two years. The results showed that CML270 was highly resistant to BLSB, and other 12 inbred lines include R15 and R09 were middle resistant. Further evaluated for reaction to BLSB to R15 and R09 through pot culture, the results showed that R15 was better than R09 at resisting BLSB. R15 was a "Three Height" inbred line bred by the Maize Research Institute in Sichuan Agriculture University.(2) The genetic linkage map was constructed with 146 SSR marker based on a maize population consisting of 229 F2 individuals from the cross Ris(resistant) x 478(susceptible), covering 1666cM on total ten chromosomes with an average interval length of 11.4cM with the method of composite interval mapping. Five QTLs conferring resistance to BLSB were detected on chromosomes 2,6and 10. The gene action for QTL on chromosomes 2, 6 was additive and QTL on chromosomes 10 was partially dominant .All QTLs could explain 28,92% of phenotypic variance .The QTL on chromosomes 2 was inferred as the major one.(3) Three other different methods of QTL mapping (single-marker analysis, composite interval mapping method and composite interval mapping method) were used to analyze the resistance to BLSB. The results showed that three methods had a similar conclusion. This denoted that the results were reliable.(4) 3 QTLs of plant height were detected, distributed 5 and 7 chromosomes respectively. There have no relevance compared with the results of QTL of BLSB. It showed that the QTL conferring resistance to BLSB is true existence.