Silver (Ag) atom interaction on beta-SiC(100) surface reconstructions is investigated by atom-resolved scanning tunneling microscopy. On the 3x2 (Si-rich) reconstruction, the adsorbate-adsorbate interaction is dominant with no surface wetting, leading to Ag cluster formation. In contrast, on the c(4x2) Si-terminated reconstruction, almost equivalent Ag-Ag and Ag-surface interactions allow selective one dimensional nano-object formation including Ag atomic wires and stripes following the substrate registry. Their orientation is mediated by anisotropic Ag atom diffusion occurring along Si-dimer rows at 25 degrees C and perpendicularly to them at elevated temperatures, suggesting dimer flipping as diffusion barrier. These metal nanowires potentially open up cross-wiring capability in massively parallel Si atomic lines network.