Diversity within maize. Image source: Sam Fentress, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=1293212
16 October is World Food Day (#WFD2016); this year’s theme is ‘Climate is changing. Food and agriculture must too.’ Jennifer Cunniff, plant scientist in CABI’s editorial team looks at how harnessing crop diversity is vital for us to meet the challenge.
Of the wide variety of edible plant species growing on our planet it’s amazing how few of them we actually include in our diet. Around 30 000 edible plant species are known, yet only 30 of these feed the world, and we are heavily reliant on a handful of cereals – rice, bread wheat, maize, millets and sorghum – provide 60% of the energy intake of the world population (FAO). This narrowing of our food base largely started with the advent of farming – before then, there is plentiful archaeological evidence that shows we were foraging across a much wider breadth of plant species (e.g. Weiss et al. 2004; Fairbairn et al. 2006). Once we formed settled societies we began to focus on crops that offered the best level of return and were best adapted to the cultivated environments we created. Furthermore, even though multiple accessions1 of our widely grown cereal species exist (naturally and through breeding) only a few dozen are grown on a wide scale. This strategy has consequences – genetic variability for adaptation to future climate change is lost.
1 A single collected variety or cultivar. It could be a wild variety, a landrace or a bred cultivar.