Breeding of Vegetable, Spice and Tuber crops (2+1)

Developments Using DNA

• It has been suggested that many of the limitations of conventional breeding can be overcome with advances in molecular biology that rely on DNA, the genetic material.
• Recombinant DNA technology, called transgene technology or genetic engineering, is the most powerful and revolutionary of the new genetics developed in the last half of the twentieth century.
  
• It is possible to isolate stretches of DNA from one organism, store it in a bacterial host, select unique combinations, and then incorporate them into the DNA of another species, where it can be expressed.
  
• This technique, which relies on cell and tissue culture, is truly a marvelous process.
  
• Refinements in the technique make it possible to concentrate mutations in desired genes, further increasing variability.
  
• Other uses of molecular biology known as genomics involve the detailed mapping of the DNA and the identification of useful stretches of the molecule.
  
• This makes it possible to improve the efficiency of selection, because it is based directly on the genes rather than the phenotypic expression of the organism, where the effects may be confounded by environment and genetic interactions.
  The limitations of the new breeding methods include technical problems, such as the difficulty of transformation, problems of gene expression, or the lack of knowledge concerning suitable genes to transfer.
  
• There are also nontechnical issues, such as legal problems, since the techniques and the genes are usually patented.
  
• However, in the short run the greatest impediment has been problems of consumer acceptability and fear of the unknown.
  
• The term "Frankenfood" has been coined to refer to food altered by the process of using exotic genes incorporated by transgene technology.
  
• No convincing evidence shows that genetic engineering has produced harmful products, and an abundance of evidence shows that many foods derived from traditional systems have inherent problems (consider the allergic reactions of many people to peanuts).
• Nevertheless, molecular techniques have incited fear of this new technology in many people.
  
• Moreover, the surplus of food in the West has reduced the imperative to make the case for the need for new technology to consumers.