My Refernces:-

http://www.dcs.qmul.ac.uk/sodarace/crossbreed/Selective%20Breeding%20Lesson%20Plan.pdf 
http://www.mtholyoke.edu/acad/criticalsocialthought/docs/criticalsocialthought/The_Evolution_of_Pantenting_Plants.pdf
http://www.bookrags.com/research/selective-breeding-ansc-04/
http://agritech.tnau.ac.in/crop_improvement/crop_imprv_breeding_methods.html
http://www.blurtit.com/q8266556.html
http://www.wisdompanel.co.uk/breedinfo/