I was wondering about my blog posts which i have to update regularly again and again daily. I add some few lines to the post daily. Will it effect my rankings in google search ?
That depends on what you add. By that I mean if you are just adding useless content and stuffing it full of keywords then it is going to hurt you. But, if you add useful content that your visitors will find useful then it should help you.
I think yes. Because Google will say that the blog is updated and updated regular. But we shouldn't wait good results.
its always Quality that matters much and yeah keeping the blog updating is a good thing in the view of SE's as i have always experienced
Make sure you don't forget to get good/quality anchored backlinks with the right keywords for your blog
Yo can't do only that and expect high rankings. Daily updating of a post with a link will only have slightly positive effect but thats not enough. Build links and add new post on regular bases.