Do the parents play a crucial role in build the characteristics of a child in early childhood or environment ?

Well, you really cannot separate family from the environment - not in today's world. In the older days, when the flow of information and communication were not so much agile and efficient, parents and other close family members did play a more significant role in a child's character development. Nowadays, though, children have more access to the outside world than ever. Technology has grown out to become a part of our daily lives. We interact with the world in one way or the other; even if the interaction is one-way.

All a child does is to learn - learn from any source whatsoever. The source could be a TV, a mobile phone, a poster on the street, a billboard advertisement, and of course, people. Still, the ones with whom the child interacts in the most direct manner; i.e. their parents, hold the fundamental key. We know that children have access to all sorts of information today. Appropriate and timely guidance with a strong emotional intelligence is the key to making sure that the child builds up a character that is socially acceptable. Nowadays, and probably in the future as well, it is about answering the question "why" to the children rather than telling them what to do and what not to. It's an age of reason, and children want reason as well. If a parent would tell their child to do something and refrain from doing something just because they said so, it may have a temporary impact. But in the long-run, it will not prove to be so effective.

In a nutshell, parents have to become a part of the "environment" to guide their children in the most effective way possible at present. I hope I answered your question.