Is it true that the geographical isolation be a major factor in the speciation of self pollinating plant species?

The answer is false.

Speciation is the process of development of a new species by evolution or by any genetic modification of the existing species in a population. Factors like natural selection, drift, geographical isolation, mutation, and drift lead to speciation. 

Geographical isolation creates the separation of the population with respect to area or geographical means. However, this is not a major factor for speciation in self-pollinating plant species because in self-pollinating plants pollination occurs between the reproductive organs of the same flower. New gene variants will not be introduced in the population and there will be no evolution of a new species. In case of cross-pollinating plants species, geographical isolation can lead to variations in traits hence leading to new species evolution.

The correct statement is - Geographical isolation will not be a major factor in the speciation of a self-pollinating plant species.