Set Default Value in Picklist in Lightning Component

Here in below example the default value in picklist is “Apple”.
Lightning Component:

<aura:component>
    <ui:inputSelect aura:Id="brandId" multiple="false" label="Select Brand">
        <ui:inputSelectOption label="Apple" text="Apple" value="true"/>
        <ui:inputSelectOption label="Nokia" text="Nokia"/>
        <ui:inputSelectOption label="Samsung" text="Samsung"/>
        <ui:inputSelectOption label="Google" text="Google"/>
        <ui:inputSelectOption label="Mi" text="Mi"/>
    </ui:inputSelect>
</aura:component>

Output: