May integrating my main category page in the index page improve my ranking of main category keyword?

[lcourse]

90% of our sales are made with products in one of our product categories. 
A search for main category keyword returns our root domain index page in google, not the category page.
I was wondering whether integrating the complete main category directly in the index page of the root domain and this way including much more relevant content for this main category keyword may have a positive impact on our google ranking for the main category keyword.

Any thoughts?

[EGOL]

Your homepage is probably more powerful than your category page and that is why it outranks it.

The category page, if it was strong enough to rank in the top ten, would likely be on the first page of the SERPs with your homepage - or instead of your homepage.  That tells me that it lacks strength rather than relevance.

The first thing that I would do is make sure that I have taken advantage of all opportunities to build internal links to the category page.  These would be links within paragraph text or a breadcrumb system of links throughout the site.

I often add lots of text to category pages.  This can be details about the items shown on the page, relevant information at the top of the page, relevant sidebar information, or supplemental information at the bottom of the page.  Use these to make links to relevant secondary pages within the category.

That's what I would do.  If that isn't good enough then you need links from external sites to obtain enough power to rank higher.

[lcourse]

EGOL thanks. Interesting point. I could see how it may slightly increase engagement and how this in turn may be a slight positive factor in ranking, even though the focus of our site is quite obvious already on the index page. 
Still my main doubt is whether in having much more comprehensive content on the main keyword on the  domain index page instead of having the same content in a category page may as such affect positively ranking of the main keyword in google, considering that google currently lists my root domain homepage instead of my category page in SERP for main keyword.

[EGOL]

If you have a site with a very limited product range (such as the items in your main category), then this might be a good idea.  Visitors will see the focus of your business when they land on your homepage and they can dig a little to find ancillary and accessory items.

However, if you offer a lot more than this main category, and the "more" are unrelated items, then making such a heavy emphasis on your homepage might not be a good idea.

Bottom line:  I would make this decision based more on customer expectations and where you sales are focused, rather than basing it on an SEO strategy.