Purpose of the National Genebank: The National Genebank in India was established to conserve plant genetic resources. This initiative aims to preserve biodiversity and ensure future food security.
Establishment Year: The National Genebank was initiated in 1992 at the National Bureau of Plant Genetic Resources (NBPGR) in New Delhi. Years other than 1992 are incorrect: 1983 is too early, 2001 is incorrect as the bank was already functional, and 2023 is an invalid date.
Conclusion: The accurate year of establishment is 1992.
Final Answer: \[\boxed{\text{The National Genebank was started in 1992.}}\]