Red is a common color, and very bright and noticeable.
There are many reasons why it makes sense that Jonas would see the color red first. It is a very bright color. It is designed to stand out. In a world where everything is meant to blend in like Jonas’s, it would be the hardest to suppress. Also, it is a common color in nature. It is in skin tones, as The Giver points out, and found in fruits and vegetables. Symbolically, it represents passion, which the community is desperately suppressing. Thus red is a natural choice for Jonas’s first color.
Jonas first sees red when he is tossing an apple around for Asher. It is just an ordinary day. It is a drill he takes part in often for Asher, who needs to practice hand-eye coordination. Yet on this day, Jonas notices the color of the apple as it flies in the air.
But suddenly Jonas had noticed, following the path of the apple through the air with his eyes, that the piece of fruit had--well, this was the part that he couldn't adequately understand--the apple had changed. Just for an instant. It had changed in mid-air, he remembered. (Ch. 3)
The changing of the apple is the first time Jonas realizes he is different. He is reprimanded for taking the apple home to study it, because he thinks there is something special about the fruit itself. Later, at the Ceremony Twelve, he realizes that what is special is in him. When the Chief Elder asks him if he has the Capacity to See Beyond, he sees the faces of the crowd change color, and acknowledges that he does.
In Jonas’s training, The Giver finally tells him what is happening to him. He is beginning to see color.
"It happened," Jonas said. "It happened to the books, but it went away again."
"I'm right, then," The Giver said. "You're beginning to see the color red." (Ch. 12)
The apple, the flesh tone, and Fiona’s hair are all things that stand out. Red stands out, because it is a bright color. The Giver explains that the community eliminated color when it went to Sameness, and that Fiona’s red hair is an anomaly that the geneticists tried to prevent.
"There were a lot of colors, and one of them was called red. That's the one you are starting to see. Your friend Fiona has red hair--quite distinctive, actually; I've noticed it before. When you mentioned Fiona's hair, it was the clue that told me you were probably beginning to see the color red." (Ch. 12)
Fiona’s hair makes her a deviation from the norm. Why the community allowed it is somewhat of a mystery. Apparently since no one can see color, they were not able to tell how much of a deviation she was, and just let it slide. Everyone has the same color skin. Everyone wears the same color clothes. No one gets to make choices. This is part of their way of controlling everyone.
Sameness also means that no one in the community has emotions. Red is the color of passion. It can represent anger, or love. These are not emotions that have a place in the community. Symbolically, it therefore has a reason for emerging first. It is a vivid color to match a vivid emotion. When Jonas considers colors, he considers the value of choosing.
"Well ... "Jonas had to stop and think it through. "If everything's the same, then there aren't any choices! I want to wake up in the morning and decide things! A blue tunic, or a red one?"
He looked down at himself, at the colorless fabric of his clothing. "But it's all the same, always." Then he laughed a little. "I know it's not important, what you wear. It doesn't matter. But--"
"It's the choosing that's important, isn't it?" The Giver asked him. (Ch. 13)
This discussion is significant. Jonas is realizing how much has been taken from them by the path of Sameness. Not only have the big life choices—choosing a spouse, and a job—been made for them, but the little ones have too. They can’t even choose what to wear each day, because they do not know the difference. They have been relegated to a bland, passionless existence. The absence of color is just symbolic of an absence of joy and choice in their lives in general.
When Jonas first sees the color red, it is the beginning of his life’s journey. He changes that day forever. He realizes that he is not the same as everyone else. At the ceremony, this is confirmed for him. His training awakens this gift in him, and gives him the rest of the colors. It all starts with the color red.