In the RFLP/PCR (RFLP, restriction fragment length polymorphism) approach of 'genotypic' mutation analysis base pair changes, small deletions and insertions are measured which are located in a restriction enzyme recognition sequence and render this site resistant to cleavage by the corresponding endonuclease.
After multiple sequence alignment of your gene of interesr of plant, you can predict difference of protein, then you can further analyze with SNP or SSR markers to get variation