In the reading of the text this word is pronounced

In the reading of the text this word is pronounced as “gui”, but in the dictionary it’s pronounced as “jun”. Which is correct, or are both correct?

I think it is generally “gui1”.
The Wenlin dictionary also lists “jun1” as a possibly pronunciation, perhaps only in the case of 龟裂.

In China , this kind of words are called as"多音字duo1 yin1 zi4".
When it means the animal–turtle,or something like a turtle,it is pronounced as “gui” ,
“jun” is pronounced only in the case of “龟裂jun1 lie4”,which meaning is “1.土地干裂 (of parched earth) be full of cracks 2.皮肤干裂 (of skin) chap”.
To distinguish “多音字” you should tell them apart from their meaning.
My English isn’t so good,wish this can help you~~
PS:I have read your text ,There are some mistakes ,Our Chinese don’t speak like that .