I am using tinymce, Is it possible to apply for only one textarea

In TinyMCE 4.x there is no deselector so you can use normal css to determine which textareas are selected and which are not.

<script type="text/javascript">
  tinymce.init({
        selector: "textarea:not(.textarea-no-styles)",
 });
</script>

For the textarea assign a class="" to textarea property, this will support for you

<script type="text/javascript">
    tinyMCE.init({
        //mode : "textareas",
        mode : "specific_textareas",
        editor_selector : "myTextEditor",
        theme : "simple"
    });
</script>

<textarea id="txtdesc" name="txtdesc" class="myTextEditor" rows="6" cols="96" ></textarea>

In the TinyMCE 3.x config you can put class selectors or deselectors to specifically enable or disable TinyMCE on textareas with certain classes, just put the class="" attribute on your textarea.

editor_deselector : "mceNoEditor" // class="mceNoEditor" will not have tinyMCE
editor_selector : "mceEditor", // class="mceEditor" will.

Source.

---

As of TinyMCE 4.0.x

selector: "textarea", // Select all textarea
selector: "textarea.editme", // Select all textarea with the class editme
selector : "textarea:not(.mceNoEditor)", // Select all textarea exluding the mceNoEditor class

Source.

In TinyMCE 4.x, you can use editor_selector option , but before that make sure you must updated mode to 'specific_textareas'

    <script type="text/javascript">
  tinymce.init({
    mode : "specific_textareas",
    editor_selector : "mceEditor",
    });
</script>

Also add css class same as editor_selector value in your textarea, as per above example it should look like this:

<textarea id='textarea1' class='mceEditor'>first text area</textarea>

now, editor will be added in those textarea that have a class named 'mceEditor'.