Conservation of indigenous vegetables from a hotspot in tropical Asia: What did we learn from Vavilov?
Conservation biologists have allocated an Indo-Burma biodiversity hotspot among 34 regions around the world especially rich in plants, animals, and other species (Myers et al., 2000). More than 13,500 different vascular plant species, of which 7000 are endemic, have been detected in this hotspot (Tordoff et al., 2012). Ninety years ago, the Russian scientist Vavilov (1926) pointed to the richness of cultivated plant species and their crop wild relatives in certain areas around the world, of which the Tropical Asia Center was one of eight. Later, Zeven and Zhukovsky (1975) applied the term Indochinese—Indonesian region of diversity for the area, which by then had been divided by various authors into an Indochinese region including Myanmar, Laos, Cambodia, Thailand, Bangladesh, and parts of Northeastern India and Southern China, and a more southern region including Malaysia and Indonesia (Darlington, 1956; Li, 1969; Schery, 1972; Janick, 2002; Nandwani, 2014). Rice (Oryza sp.), mungbean (Vigna radiata), gourd species, and indigenous vegetables were among crops that Zeven and Zhukovsky (1975) listed in the Indochinese region of diversity.
Vavilov noted the importance of collecting different varieties, and the wild relatives, of cultivated plants as genetic resources for use in crop improvement. In 1935, he claimed that for plant breeders there was no other choice but to become geographers (Vavilov, 1935). At that time, the genepool available to plant breeders was relatively narrow. To adapt crops to a wider geographical zone and to move forward in breeding, Vavilov started collecting germplasm worldwide and conducted expeditions to India, China, and other locations. He also received samples of leguminous species from Myanmar. In a later overseas collection mission in Myanmar, Kobylyanskaya, and Chepurin from the Vavilov Institute collected 201 accessions of cereals and legumes from the central and south parts of the country (Loskutov, 1999). More recently, Japanese scientists have conducted missions to Myanmar to collect wild rice (Uga et al., 2004).
As global populations increase and climates change, a greater diversity of genetic resources is needed for crop improvement. Agriculture needs to produce more food under more unpredictable climatic conditions (McCouch et al., 2013; Nierenberg, 2013; Betts and Hawkins, 2014). Genetic resources have indeed been collected; according to the UN Food and Agriculture Organization (FAO, 2010), rice is well-represented, with more than 770,000 accessions in genebanks around the world. Horticultural crops such as vegetables tend to be highly underrepresented in the conservation system, especially considering their nutritional importance (Yang and Hanson, 2009). Here we demonstrate, despite 90 years of awareness, how indigenous vegetables are poorly represented in the global conservation system and argue for the importance of safeguarding agrobiodiversity in its centers of diversity. We use tropical Asia as a case area but narrow our focus to Myanmar and indigenous vegetables relevant for this country.