The easiest and the quickest i could think of is
private void Form1_Load(object sender, EventArgs e)
{
DataGridViewRow row = (DataGridViewRow)dataGridView1.Rows[0].Clone();
row.Cells[0].Value = "XYZ";
row.Cells[1].Value = 50.2;
dataGridView1.Rows.Add(row);
foreach (DataGridViewRow r in dataGridView1.Rows)
{
row = (DataGridViewRow)dataGridView2.Rows[0].Clone();
row.Cells[0].Value = r.Cells[0].Value;
row.Cells[1].Value = r.Cells[1].Value;
dataGridView2.Rows.Add(row);
}
}