Resistance to yellow mosaic virus in bhindi (Abelmoschus esculentus) was transferred from a wild species and resulted in a new variety of Abelmoschus esculentus called -

 Resistance to yellow mosaic virus in bhindi (Abelmoschus esculentus) was transferred from a wild species and resulted in a new variety of A. esculentus called Parbhani kranti.Transfer of resistance genes is achieved by sexual hybridisation between the target and the source plant followed by selection.

In the above example sources of resistance genes that are in the same crop species, which has to be bred for disease resistance, or in a related wild species. 

Conventional breeding is often constrained by the availability of limited number of disease resistance genes that are present and identified in various crop varieties or wild relatives.In such cases mutational breeding is useful