Unfortunately it looks like that your seedling is rotting. To be sure, gently remove it from the medium and inspect the roots and stem. Anything discoloured/brown is rot. But again, I think it is a goner. :-(

Noooo, say it isn't so :( I inspected the roots, well one root and it seems ok. So I'll just keep him out of the sun and water and keep my fingers crossed.

What may be the cause though? Too much sun, water or somethings else?

Has it been watering with the rains? How hot is it getting there. That is a prime heat time of the day and it could be drying out to fast.

Hi Marcia, i believe you are correct. It gets the full afternoon sun and the soil is usually dry. I have since started misting them during lunchtime and so far they are looking better. I did loose a few, but it is a learning experience as this is my first time germinating AO seeds