Differential Silica Deposition in Maize Leaves of Sorghum Downy Mildew Susceptible and Resistant Recombinant Inbred Lines of Maize Derived from UMI79 and UMI936 (w)

The recombinant inbred lines (RILs) along with parents (UMI79and UMI936 (w)) were screened for sorghum downy mildew (SDM) disease reaction in field with conidial inoculation of Peronosclerospora sorghi. Twenty days post inoculation, sampling was done for the third leaf of three susceptible and three resistant RILs along with parent for cytological analysis of silica cell deposition with scanning electron microscope (SEM). SEM analysis revealed that the resistant genotypes (UMI936 (w); RILs 101, 114 and 131) have higher number of silica cells than the susceptible genotypes. The absence or negligible number of silica deposition in the epidermal cells of susceptible genotype was noticed. Thus, our preliminary study indicated that silica might have a significant role in positively regulating sorghum downy mildew disease resistance in maize and further quantification of silica content may advance our knowledge about degree of disease resistance conferred by deposition of silica in epidermal cell of maize leaves.