Can I claim a share in my father’s property on the basis of unregistered Will?

Can I claim a share in my father's property on the basis of unregistered Will? My father is not alive. He had some agricultural lands. He was writing a vasiyat but the vasiyat is not registered due to lack of knowledge. My brother has transferred all agricultural lands in his name. I want to challenge that transfer but I have only unregistered Will. Can I claim a share in my father's property on the basis of unregistered Will?

There is no difference between registered and unregistered Will towards its legal validity. If the prevailing circumstances are supporting the creation of Will then you should apply for its probate or letter of administration. 

When you successfully prove in the court that the said Will is genuine then you become entitled to claim a share in your father’s property as per the Will however, the Will is unregistered. 

You should also file a civil suit for the cancellation of transfer (mutation) of agricultural lands which your brother got in his name. If there is a Will at the death of the owner (testator) the property will be settled according to that Will. 

However, your brother has wrongly mutated all agricultural lands in his favour. If the property may devolve through the rule of inheritance he has no right to get all properties in his name because there are more legal heirs than one. 

In this situation all the legal heirs will get equal share. Hence, you should follow the above said procedure to get your right in the agricultural lands of your father.