By default, the MajorTimeRuler property is "01:00" which indicates that the major rulers are shown from hour to hour. You can use the MajorTimeRuler property to programmatically change the major ruler occurrence.  

The DayStartTime property defines the starting time of the day, and the DayEndTime property defines the ending time of the day. The MajorTimeLabel property defines the time label to be shown on the major rulers, while the MinorTimeLabel property specifies the time label to be shown on minor rulers. The MajorLabelColor property indicates the color to show the labels on major rulers. The MinorTimeRuler property indicates the time to show the next minor label/line.