JSFiddle - React, Tailwind, and code Playground
HTML
<script src="https://code.jquery.com/jquery-2.2.3.min.js"></script>
<div class="wrapper">
<table id="table_cultures">
<tr>
<td>Just a string</td>
<td>Dropdown</td>
<td>
<div class='foo'> something..</div>
</td>
</tr>
</table>
<button id="plus_button" onclick="addRow()">+</button>
</div>
JavaScript
$(".wrapper").on("click", "#plus_button", function(event) {
$("#table_cultures td:last").clone().appendTo("#table_cultures tr");
});