There is no qualiforcation for SEO as far as I know, there are certifications you can get but none of them are really worth it. To get an SEO job its all about experiance really and prooving you know what your doing, examples of work you have done previously ect. Something that can help though is a degree in computer science where you have specialised in web development, but this means very little compared to experiance and examples of previous work. Or a lower level of recognised web development certifications to show you have a good understanding of HTML/XHTML, CSS, javascript, PHP, SQL.
You need to know different technique, how they distinguish from each other and how to implement it to get a better result. The more experience you have, the more valuable you are. No qualification really needed but basic knowledge on computer, website and web design is good to understand and implement different technique.
basic knowledge, i'd have to say onsite SEO. even without offsite SEO like building backlinks, it can get done. If you have a site that a search engine bot can successfully recognize, then you quite possibly could be alright.
In my opinion, a Seo profissional should be very pacient, organized and he has to do which like! Sorry my bad english!
There is no particular degree to become SEO expert. Basic knowledge of SEO is essential. The enthusiasm to learn new techniques regularly is most important.
Learn Google Webmaster Help http://support.google.com/webmasters/bin/answer.py?hl=en&answer=35769 It is quite helpful.
The big thing is the passion to learn more about SEO. This requires spending time thinking and learning it. Even better if you have the skill to think outside the box to try new things (aka. entrepeneur)