UIPickerView中的行分隔符

如何在我的选择器视图中隐藏分隔符.这是截图 .

这是我的自定义UIPickerView的代码.

- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view {

UILabel *label=[[UILabel alloc]init];
label.backgroundColor = [UIColor clearColor];
label.textColor = [UIColor whiteColor];
label.textAlignment=NSTextAlignmentCenter;

switch (component) {
    case 0:
        label.text=[_hourArray objectAtIndex:row];
        label.font = [UIFont fontWithName:@"MYRIADPRO-REGULAR" size:70];
        break;

    case 1:
        label.text=[_minutesArray objectAtIndex:row];
        label.font = [UIFont fontWithName:@"MYRIADPRO-REGULAR" size:70];
        break;

    case 2:
        label.text=[_ampmArray objectAtIndex:row];
        label.font = [UIFont fontWithName:@"MYRIADPRO-REGULAR" size:15];

        break;

    default:
        break;
}
return label;
}

-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {
return 3;
}

请帮帮我.谢谢