Picture the harvest festival scene at a typical Scottish school and yams do not immediately spring to mind. But at Preston Street primary, the success or otherwise of this particular sub-tropical food crop has a special place in the celebrations. At a school such as this, located close to the Scottish Parliament building as well as a number of medical and higher-education establishments, a certain cosmopolitan outlook is perhaps to be expected. After all, in the average week, some 25 cultures might be represented among Preston's 280 children.
But concern for the yam harvest has a more specific focus - namely, a primary school more than 4,000 miles away, in Northern Ghana. It began two years ago, when a parent with Ghanaian family connections paid a visit to the village of Saboro and returned with a collection of photographs and artefacts.
Alison Noble, the head at Preston Street, says that staff saw at once how setting up a link with the school might lend a global dimension to teaching and learning. They approached Link Community Development, an organisation that helps to facilitate partnerships between schools in Africa and the UK, and were soon in regular contact with staff and children at Saboro.
"I suppose initially we thought of the link as an opportunity to encourage enterprise through raising funds to support Saboro," says Ms Noble. "But we soon realised that it was so much more, and that there was great learning potential there. It is contributing to significant areas of the curriculum and learning and teaching in the school.
"In terms of literacy, the children are now writing letters, using IT skills, taking photographs and sending them out, and using word processing skills. Meanwhile, the fundraising - the enterprise side - has grown, from bring-and-buy sales and coffee mornings to making and selling magazines.
"What has impressed me is that it has been the children volunteering and asking, 'Could we write a magazine and could we sell it to the other girls and boys in the family and give the money to Saboro?' As a result, we have had small writing groups at playtime and lunchtime and in class.
"The children are very enthusiastic about the letters, drawings, photographs and reports that we receive from Ghana. They tell us what they have done with the money we send - bought some books, perhaps, repaired a roof, or planted some trees that have environmentally enhanced the area.
"Reading this factual information is again supporting the literacy curriculum. Our children are listening and talking. They are reading the reports for information, and looking for the meaning in the words."
Although the school in Ghana is of a similar size to its Edinburgh partner and has roughly the same number of children, it is very different in terms of facilities. There are no toilets or electricity, for a start.
Nevertheless, the children at the two schools have found that they share an interest in football, while their teachers have exchanged school and career development plans, school handbooks and parent and pupil information.
With its varied population, Preston Street primary is well-practised at celebrating cultural diversity, so reports on the Ghanaian yam harvest are a welcome addition to assemblies and gatherings. The parent-teacher association holds regular international food evenings, and a forest of "family and language trees", each of whose leaves describes a different culture, gives an exotic feel to the traditional Victorian fabric.
Children are taking part in a family story project, sharing tales told by their parents and grandparents. This sharing of ancestral heritage will naturally extend to the children in Saboro, whose own family stories will no doubt be read with enthusiasm by their friends in Edinburgh.
At the same time, Preston Street is working towards achieving eco-school status, an aim which Alison Noble believes chimes in well with the growing emphasis on global awareness. "We are trying to embed the Saboro link within the wider eco-school project," she says. "After the recent elections for our Kids Council, we had a tour of the Scottish Parliament and held a meeting in a committee room there. I suppose what we're trying to say to the children with all this is: 'The Parliament's going to make a difference and you're making a difference as well, within our school, within our local community and globally'."
For more information about Link Community Development and its school sponsorship and Global Teachers programmes, visit www.lcd.org.uk