Study On The Heredity Of Resistance To Maize Sheath Blight

The maize inbred line 478 which is susceptible to maize sheath blight , maize inbred line CML270 which is resistance to maize sheath blight , three (CML270.478) F2 populations, (CML270.478) . CML270 backcross population and (CML270.478) X 478 backcross population were planted. Then the materials were inoculated artificially with maize sheath blight pathogen AG-l-IA. The resistance statistics showed that the resistance to maize sheath blight behaves as character between quality character and quantity character. The heredity of resistance to maize sheath blight is master of at least four to seven pairs central genes, while it is influenced by multi-genes which have low influence to the heredity.The genome DNA of maize inbred CML270 and 478 were extracted and produced by PCR with the primers designed according to the sequences of known plant disease resistance genes and the conserved region of these genes. The sequences of products had no homologous to known plant disease resistance genes , but they were homologous to other known plant genes. The sequence of the product produced by PCR of the maize inbred 478 with the primer designed according to the sequence of Pto gene in tomato were homologous to maize retrotransposon gene Cinful-1. We estimate the segment is possibly part of maize retrotransposon gene Cinful-1.Total RNA in leaf sheath of maize inbred CML270 were extracted at 0 ,6, 12, 24, 36, 48hrs after being inoculated artificially with maize sheath blight pathogen AG-l-IA. The cDNA retrotranscribed from these RNA were produced by PCR with the primers designed according to the sequences of known plant disease resistance genes and the conserved region of these genes. There were no differences between the products of different time after being inoculated with maize sheath blight pathogen. So we estimate that the expression of the genes resistance to maize sheath blight is constitutive genes.