Does not save the information in database, error "Object reference not established as instance of an object"

I have the following code and when saving in my database I get the following error: "Object reference not established as an instance of an object"

Imports MySql.Data.MySqlClient

Public Class Ingresovehiculo
    Dim conexion As MySqlConnection
    Dim Comando As MySqlCommand


    Private Sub BtnSalir_Click(sender As Object, e As EventArgs) Handles BtnSalir.Click
        Form1.Show()
        Me.Hide()
    End Sub

    Private Sub Ingresovehiculo_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Try
            conexion.ConnectionString = "server=localhost; user=root; password=;database=almacenca;"
            conexion.Open()
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
    End Sub

    Private Sub Btnagregar_Click(sender As Object, e As EventArgs) Handles Btnagregar.Click
        Try

            Comando = New MySqlCommand("INSERT INTO ingresovehiculo(tipo, marca, modelo, descripcion)" &Chr(13) &
                                       "VALUES(@tipo,@marca,@modelo,@descripcion)", conexion)
            Comando.Parameters.AddWithValue("@tipo", ComboBox1.SelectedValue)
            Comando.Parameters.AddWithValue("@marca", ComboBox2.SelectedValue)
            Comando.Parameters.AddWithValue("@modelo", Txtmodelo.Text)
            Comando.Parameters.AddWithValue("@descripcion", Txtdescripcion.Text)
            Comando.ExecuteNonQuery()
            MsgBox("DATOS GUARDADOS")
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
    End Sub
End Class