Shade every other task row

Answer:

You can use the Gridline/Shade option.

This can be done for all task rows in an "every other line" pattern.

1. On the Format tab, choose Horizontal Gridlines and Shading...

2. Select the Shading tab.

3. Make your color choices.

4. Click to select the areas to be shaded (left columns, right columns or graph area).

5. Choose an Alternating Pattern of Odd or Even.  Odd will shade every other row starting with row 1.  Even will shade every other row starting with row 

6. Click OK.