Natural Rubber (Hevea brasiliensis [Willd. ex A. Juss.] Müll. Arg.): History, Domestication, Genetic Diversity, Conservation and Cultivar Improvement

The ‘para rubber tree’ Hevea brasiliensis, originated in the Amazon forests, is a recently domesticated plantation crop with a pantropical distribution across Asia, Africa and America. Even though the ancient tribes of Mesoamerica are known to have extracted rubber from latex of rubber-yielding plants like the Panama rubber tree (Castilla elastica) for more than 3600 years ago, the potential of H. brasiliensis in the exploitation of natural rubber (NR) was opened up to the modern world only by the turn of nineteenth century with the invention of vulcanization by Charles Goodyear in 1839, followed by the flourishing of automobile industry. The introduction and extensive cultivation of H. brasiliensis in Southeast Asian countries is by far a fascinating story unravelling the introduction of rubber seeds outside Brazil, the fall of rubber boom in its native habitat due to disease infestation, strategic importance during wartime and establishment of systematic plantations in tropical Asia by the British colonies with R & D support. H. brasiliensis has a natural proclivity to cross-pollination, and open-pollinated seeds were the initial planting materials at the beginning of rubber cultivation. Ever since the advent of bud grafting techniques, hybridization followed by clonal selection is predominantly adopted world over for developing high-yielding Hevea clones. Due to the widening demand-supply gap for this raw material, today cultivation is extended to non-traditional areas experiencing a multitude of biotic and abiotic constraints. An overview of the history, evolution and domestication, biology and breeding, genetic diversity and the need for conservation is highlighted in this chapter, outlining the status of breeding and conservation in India.