The gentle slopes of the Cornish countryside and the foothills of the Himalayas have been united by the humble cuppa.

The UK's only tea plantation, Tregothnan Estate, near St Michael Penkivel outside Truro, is to be twinned with the Indian city of Darjeeling, famous for its black teas.

The unlikely partnership was proposed by a visiting delegation from the Confederation of Indian Industry (CII). Officials suggested the link-up in recognition of climatic similarities between the valley mists of West Bengal and the warm winters of Cornwall.

Tregothnan garden director, Jonathon Jones, who is invited to Calcutta next month to address a special forum, said it was "wonderful news" for "two great tea-drinking nations".

"This exciting twinning will help us exchange PhD students and collaborate on research projects," he said. "There is so much good in tea that isn't yet known – we could also do with some help processing our leaves."

Darjeeling has been growing tea since the 19th century whereas Tregothnan only harvested its first commercial leaves a decade ago. However both estates grow enormous rhododendrons and magnolias and hope the union will bring economic benefits. Friendly rivalry between the two has existed for many years over who first gets the large pink blooms of the magnolia campbellii into flower, an indicator of a good spring flush of tea.

The twinning will take place at a ceremony next year attended by Lord Falmouth, whose family have lived at Tregothnan since 1335.

Ramgopal Agarwal, chairman of the CII's Bengal branch, said: "Tregothnan is an innovative estate on such a scale that we feel it is a tremendous opportunity for both regions to really join forces and increase tea tourism."