data one;
  input block trt y;
  cards;
1 1 180
1 3 173
1 2 177
1 4 182
2 4 177
2 2 165
2 3 170
2 1 162
3 1 162
3 2 165
3 3 163
3 4 169
4 1 180
4 2 183
4 4 185
4 3 179
5 4 163
5 3 158
5 1 159
5 2 165
;

proc glm;
  class block trt;
  model y=block trt;
  lsmeans trt / adjust=tukey pdiff;
  lsmeans trt / adjust=dunnett pdiff;
  estimate 'trt 1 mean' intercept 1 trt 1 0 0 0;
  estimate 'trt 4 mean - trt 1 mean' trt -1 0 0 1;
run;