Text wrapping with dot (graphviz)

I used the code below to create a graphic using dot (graphviz).

digraph
{
  node [color=Blue,shape=box]

  1.1 [label="Frequency of t exceeds upper threshold"]
  2.1 [label="t has d-mutant tiles"]
  2.2 [label="Valid"]
  3.1 [label="Frequency of t exceeds lower threshold"]
  3.2 [label="Frequency of t exceeds lower threshold"]
  4.1 [label="Insufficient evidence"]
  4.2 [label="Valid"]
  4.3 [label="t has only one d-mutant that exceeds lower threshold"]
  4.4 [label="Are there any d-mutant tiles with significantly higher frequencies?"]
  5.1 [label="Insufficient evidence"]
  node [color=Green] 5.2 [label="Correct t to t'"] node [color=Blue]
  5.3 [label="t has a d-mutant tile t' that is closer than all other d-mutant tiles and for which a corrected base has a higher quality score"]
  5.4 [label="Valid"]
  6.1 [label="Insufficient evidence"]
  6.2 [label="t' is unique"]
  7.1 [label="Insufficient evidence"]
  node [color=Green] 7.2 [label="Correct t to t'"] node [color=Blue]

  1.1 -> 2.1 [label="no"]
  1.1 -> 2.2 [label="yes"]
  2.1 -> 3.1 [label="no"]
  2.1 -> 3.2 [label="yes"]
  3.1 -> 4.1 [label="no"]
  3.1 -> 4.2 [label="yes"]
  3.2 -> 4.3 [label="no"]
  3.2 -> 4.4 [label="yes"]
  4.3 -> 5.1 [label="no"]
  4.3 -> 5.2 [label="yes"]
  4.4 -> 5.3 [label="no"]
  4.4 -> 5.4 [label="yes"]
  5.3 -> 6.1 [label="no"]
  5.3 -> 6.2 [label="yes"]
  6.2 -> 7.1 [label="no"]
  6.2 -> 7.2 [label="yes"]
}

As you can see, some of the boxes in the graphic have a lot of text in the label. I can insert \n characters to make sure the boxes aren't too wide, but I'm wondering if there is a way I can set the width of the boxes and then have the box labels do a hard wrap. Is this possible?