The cross performed between two plants belonging to different species (having different characters) is referred to as hybridization as both the plants are heterozygous for two different traits. Hence (i) is correct.

Cross between two varieties is called either Inter -varietal hybridization (if varieties are different) or Intra-varietal hybridization (if varieties are same). Hence statement (ii) is wrong.

Introducing genes of desired character into a plant gives genetically modified crop by modifying the DNA of plant. The aim is to introduce a new trait to the plant which does not occur naturally in the species. Hence statement (iii) is correct.

Cross between plants of two species is called as inter-specific hybridization. Hence statement (iv) is wrong.