For colder regions, zones 3 through 6, varieties such as McIntosh, Haralson, or Honeycrisp are the best heirloom apple trees to grow because of their cold hardiness and higher chilling hour ...

Countries like the UK, with around 1,000 hours of this chill-time, can produce almost any apple variety. But in India areas with those conditions are more limited.

Chill hours vary by type and can be as long as seven to nine weeks (e.g., pear and apple). Low-chill fruit trees may be available.