I have not read the book - so maybe someone can help me. How did Genco come about? Why did they name it that, did Genco have more money to put down or in honor if him and his father helping Vito out?

Well, Genco's father owned the market that Vito worked at when he was young. He and Genco became friends, and used the money that Vito had collected from the neighborhood to start a business in olive oil. Not sure why they named it after Genco, but I am thinking that since he already had a background in grocery markets, Genco kind of spearheaded it and Vito lended his finances. Genco eventually became consigliere to the family.

Vito was too modest to name the company after himself according to the novell.

There is little doubt in my mind that any excessive money garnered illegitimatly, i.e. through protection rackets, would have to be laundered. As such he used Genco. If the business was run by his old friend (who's family already had the capital on paper to legitimize the existence and a business like that) it would not draw attention to him. By taking a diminished role he would A) do a favour to his old friend (as GF II pointed out, he felt indebted to Genco's father) and B) Allow for a perfect money laundering front.

Genco Olive Oil was Vito's "front," named after his boyhood pal because Vito was modest and because he wanted to hide behind Genco, not put his name out front where it would attract attention. As the business grew to be the biggest olive oil importer in America, so did its cover for Vito's growing wealth, and whatever business he had in Sicily.

I never been clear on Genco, iknow he was consiglirie, but he never reall explorded in the novel or films esp. since he is such a prominant figure in the crime family

Genco was in part 2 in alotta of the flashback scenes. and he was in part 1 when he was on his death bed but they deleted that scene out. He is also discussed pretty well in the novel too.

I believe Vito wanted to be in the shadows and Genco wanted to be more legitamite AT THE TIME so he gave him the name, while Vito can continue to run the neighborhood.