Ion-select-options set Default Value Ionic 4

Ionic Framework
1

<ion-select [(ngModel)]=“themeType” name=“resultItem”>

    <ion-select-option *ngFor="let resultItem of result; let i=index" [value]="resultItem.TypeId">{{resultItem.TypeDescription}}</ion-select-option>

  </ion-select>

This is My Code I have Select and save Value After I set The saved value The Value cannot set to the options. Why?

need help to solve this.
I am Using Angular 7 and ionic 4