Screening and field trials of high-carotenoid sweet potatoes in Solomon Islands and Papua New Guinea to improve human vitamin A status

A collaborative project in Solomon Islands and Papua New Guinea (Lowlands) has started screening for carotenoid-rich sweet potato varieties (i.e. orange-fleshed sweet potato, OFSP), along with carefully considering the social aspects of these and other micronutrient-dense foods, how they fit into the traditional food system, and what factors may be important for promoting them. This project was prompted by studies which indicate suboptimal vitamin A status in population sub-groups in Solomon Islands and PNG, notably in infants, children and pregnant or nursing women. Moreover, during the past 50 years throughout the Pacific and PNG there have been large increases in rates of the so-called metabolic/lifestyle diseases such as diabetes, obesity, cardiovascular disease and certain cancers. These result from overconsumption of refined, nutritionally-poor products such as white flour, white rice and sugar, combined with lack of proper exercise.
Agencies involved include ACIAR, HarvestPlus, International Potato Centre (CIP), Secretariat of the Pacific Community (SPC), Kastom Gaden Association (KGA), Solomon Islands Ministry of Agriculture and Livestock, Island Food Community of Pohnpei, PNG National Agricultural Research Institute (NARI), World Vision, Queensland Department of Primary Industries and Fisheries (QDPIF), and Makira Ulawa Province and community groups.
Over 50 orange/yellow sweet potato varieties were collected and analysed (using high-performance liquid chromatography), as well as a selection of sweet potato leaf samples and other food crops. Collecting areas included the remote Santa Cruz Islands, Makira, Santa Ana, Guadalcanal, Western Solomons/Isabel (by Pita Tikai, KGA), and samples were also sent from Madang, PNG by World Vision. Project activity in PNG was limited in 2007 due to the leader's commitments to biofortification programs in several countries, and also the project aim of being mostly Solomons-based.
Promising varieties (with beta-carotene levels over 100 mg/kg dry weight, and which are highly regarded by local consumers for their insect/pathogen resistance, yield, flavour, texture and storage ability) have been identified from this survey and are being multiplied by KGA. This is where the workshops, talks and distribution of promotional material (see below) are essential, as knowledge of the health benefits of micronutrient-rich local foods is not widespread at present. In addition, financial support has been provided to key agriculture and education officers on Makira, who are involved in sweet potato field trials, banana seed gardens, training programs for women, and agricultural extension in the Star Harbour/Weathercoast area.
Cassava and sweet potato leaves were found to be useful sources of carotenoids; for example the reddish leaves of Beraha cassava contained nearly 400 mg/kg of beta-carotene. Cooking in coconut cream enhances carotenoid bioavailability.
Seven nutritional workshops promoting OFSPs, high-carotenoid bananas and nutritious local foods generally, and including information gathering, were held on Makira in October 2007. The workshops were led by Dr Lois Englberger, renowned anthropologist and nutritionist from the Island Food Community, Pohnpei, Micronesia. There was great interest among local people in this activity and over 700 people attended the workshops in total. Participants were particularly keen on the "Go Local" and "Going Yellow" slogans. Several of the workshops were held on the Makira Weathercoast, a remote area with nutrition/food security/income/transport issues.
The social research methods used included ethnography, key informant interviews, informal focus group discussions, free listing, pile sorting, photography, market survey and literature review. In addition, rare high-carotenoid banana germplasm was collected and transferred to Fiji for tissue culture. Names of the sweet potato and banana varieties, as well as characteristics, beliefs, practices, and traditional knowledge, and factors relating to production, marketing, consumption, and acceptability, all of which impact on the potential for promoting these crops, were explored. Plans are underway to initiate similar efforts on other islands of Solomon Islands and in PNG (in Madang Province, where the population has been identified as having the highest risk of vitamin A deficiency in PNG) in collaboration with World Vision and NARI. Suitable promotional materials (including posters of high-carotenoid local foods) are being developed.
In addition to the survey and social marketing components of the program, imports of OFSP varieties with valuable traits from CIP Peru (via SPC, Fiji) and Indonesia (via QDPIF, Australia) are in progress. Once they clear quarantine, these imported varieties will be tested at several sites in Solomon Islands and PNG.
Health benefits of OFSP aside, the AusAID report "Solomon Islands Smallholder Agriculture Study (Vol 1)" recommended efforts to raise productivity of staple food crops in Solomon Islands to give a much needed boost to the economy. Increasing the appreciation of sweet potato and banana diversity is part of the larger ongoing effort that is needed.
APPENDICES
1. A report, "An exploratory study of banana and sweet potato varieties, including beliefs, practices, and potential for promotion: a collaborative project with communities on Makira Island, October 1-16, 2007" by Englberger et al.
2. Progress report for HarvestPlus, January 2008 by G Lyons
3. Results of 2007 OFSP beta-carotene survey.
4. ACIAR Newsletter article by Englberger et al.