How to specify number of branch in decision tree in R

I'am using decision tree to predict future behavior of my dataset.It contains decision variable called "rate" That I want to predict.I have many characteristics that influences on the rate column but when I apply decision tree algorithm. I gave only one level which is ibt as mentioned on the code below:

ad.apprentissage= rpart(rate~vqs+ibt+tbt+bf+n, data=filteredDataFinal)

node), split, n, loss, yval, (yprob)
      * denotes terminal node

1) root 27 15 4 (0.4074074 0.4444444 0.1481481)  
  2) ibt< 1.516 11  3 3 (0.7272727 0.2727273 0.0000000) *
  3) ibt>=1.516 16  7 4 (0.1875000 0.5625000 0.2500000) *

Now, I'm asking on how to add other level to the tree like tbt characteristics.

Solution

Maybe I'm missing your question, but tree size in rpart is controlled by the complexity parameter (cp). You can try different values to get a different sized tree.

ad.apprentissage= rpart(rate~vqs+ibt+tbt+bf+n, data=filteredDataFinal, cp=0.1)