Approximately, 50% of total world plant species are present in…
The principle of plant biotechnology explains that photosynthetic engineering and nutrient pathways support biofortification. Hence tropical rain forest fits best because it supports metabolic engineering in crops, as documented in authoritative sources on plant biology.
Ref: Taiz et al., Plant Physiology and Development, 6th Edition, Chapter 7, Photosynthesis, discusses light reactions, Calvin cycle and metabolic engineering examples like Golden Rice providing insight into plant biotechnology.