Best Pratice In Inheritance - Three Classes Employee, Manager And Salesman. Manager And Salesman Classes Inherits Employee Class

I have three classes Employee, Manager and Salesman. Manager and Salesman classes inherits Employee class.

Employee :

Public MustInherit Class Employee
' Field data.
Protected empName As String
Protected empID As Integer
Protected currPay As Single

[CODE]...

Manager :

Public Class Manager
Inherits Employee

[CODE]...

Salesman :

Public Class Salesman
Inherits Employee

[CODE]...

Now I have created a object of salesman and manager using the following code:

Dim objSalesMan as Employee=new Salesman("xyz",1,2000,5000)
Dim objManager as Employee=new Manager("abx",2,5000,"production")

Is this a good programming pratice or should I use:

Dim objSalesMan as new Salesman("xyz",1,2000,5000)
Dim objManager as new Manager("abx",2,5000,"production")