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Tropical fruit tree species – such as mango, rambutan and mangosteen – are excellent sources of crucial vitamins, minerals or anti-oxidants and thus essential as supplemental food for a nutritionally-balanced diet. They are important resources for the well-being of many people around the world and can play a major role to enhance both household income and national revenue. The genetic diversity – the variability among and within tree species that makes them adaptable to local conditions – of tropical fruit trees is increasingly threatened by factors ranging from changes in land use, habitat loss, globalization and climate change.

In order to improve the livelihoods and food and nutrition security of communities in Asia – a region that boasts over 400 different fruit tree species – through the conservation and use of tropical fruit tree genetic resources, Bioversity International embarked on the ‘Tropical Fruit Tree’ project in 2009. The project was active in India, Indonesia, Malaysia and Thailand, home to four globally important tropical fruit species with rich diversity in the region: citrus (Citrus spp.), mango (Mangifera indica), rambutan (Nephelium lappaceum) and mangosteen (Garcinia mangostana)  and their wild relatives.

Most of Bioversity International and research partners’ findings were obtained through active engagement of farming communities and practitioners along the research process, through the application of different participatory and empowering tools.

Tropical Fruit Tree project

Celebrating tropical fruit tree custodians

Across the globe, not just in South and Southeast Asia, there are ‘custodian farmers’: people who actively maintain, adapt and disseminate agricultural and tree biodiversity and the traditional knowledge related to it.

In order to identify these actors and tell their stories, Bioversity International and partners created a standardized approach, went to the field and studied the success of Indian, Indonesian, Malaysian and Thai custodians. Learning from the farmers, identifying the gaps and bringing in scientific knowledge, the organizations worked on strengthening their capacity in the country and scaling it up to the whole region.

Key figures can be found in the just-released Tropical Fruit Tree Diversity book that is part of the Issues in Agricultural Biodiversity Series or in this video featuring 20 custodian farmers.

Download this guide for the identification and importance of custodian farmers.

Read the blog: New Publication Reveals that Farmers are the Best Source for Conservation Practices

Download the book

Tree selection from farmers' orchards is the best strategy for under-researched fruit crops

Plant breeding is an expensive and a long term process and – in the case of perennial tropical fruit trees like citrus, mangosteen, rambutan, and mango – it is a life-long job – if not longer. Farmers’ orchards and home gardens constitute the majority of the diverse and often unexplored and untested portfolio of fruit tree genetic resources. They house the fruits of thousands of years of observation, selection, domestication, multiplication and exchange of naturally introgressed materials, which all is done by custodian farmers. With the abundance of such useful diversity, research into leveraging this usefulness through such a simple technique has potential to improve the income and livelihoods of farmers without waiting for a generation to go by.

Bioversity International researchers and partners carried out on-farm diversity assessments and surveyed 36 communities of four countries (India, Indonesia, Malaysia and Thailand) to identify farmers’ best varieties or genotypes with distinguished or unique traits (e.g.  colour, taste, shape, quality, aroma, local adaptability, disease resistance) that add value and trigger or create market demand for specific varieties.
Many custodians were visited and interviewed and a total of 95 varieties of mango, 32 citrus, 5 garcinia and 2 nephelium were identified across the four countries. These best-performing trees – also known as elite trees - were collected and multiplied in 126 fruit tree nurseries and made available to over 77,000 farming households. These seedlings can be used by plant breeders for future crop improvement.

At the annual farmer fair organized by the University of Dharwad, India, farmer-selected tree seedlings turned out to be in much higher demand than most of the materials from the forest department– as people trusted the eye of the local specialist – especially for locally-adapted tree species such as kokum (Garcinia indica) and aromatic mango (Mangifera indica) which is used for making traditional home-made mango pickle. As it takes a long time before you can evaluate your saplings – farmers preferred locally tested materials instead of those coming from afar.

Of these, a total of 99 farmer varieties of four species were registered by the competent authority of government - 16 citrus, 6 garcinia, 75 mangifera and 2 nephelium in the name of the local community or the custodian farmer. This is the first step in recognizing the eminent role that farmers play in the conservation and use of fruit tree diversity and means that they can multiply and commercially market these fruit trees.


The ‘Tropical Fruit Tree’ project – also called ‘Conservation and Sustainable Use of Cultivated and Wild Tropical Fruit Tree Diversity: Promoting Sustainable Livelihoods, Food Security and Ecosystem Services’ – was launched in 2009 with the funding of the Global Environment Facility (GEF). It is implemented through the United National Environment Programme (UNEP) and lead by Bioversity International with the four country partners:

  • India: Indian Council of Agricultural Research (ICAR)
  • Indonesia: Indonesian Centre for Horticulture Research and Development (ICHORD) Malaysia: Malaysian Agricultural Research and Development Institute (MARDI)
  • Thailand: Department of Agriculture (DoA)

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