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.
A young man in drought conditions in Ethiopia (Author: USAID African Bureau)
We are all told to improve our diet; increasing our fruit and vegetable consumption and reducing our red meat intake. But a new study, ‘Global and regional health effects of future food production under climate change; a modelling study,’ published in The Lancet has revealed that climate change may make eating our 5 a day more challenging, and that subsequent dietary shifts and changes in body weight will lead to more than half a million additional deaths worldwide by 2050.
Hunger and undernutrition are amongst the most persistent global development challenges. Part of Millennium Development Goal 1 is to ‘Halve, between 1990 and 2015, the proportion of people who suffer from hunger’ (UN, 2012). With global numbers of undernourished people static at 870 million for the past 5 years and undernutrition contributing to the deaths of 2.6 million children under five each year (FAO, 2012), at the global level, clearly insufficient progress has been made towards achieving this target. But, at a national level, how are governments doing?
Pity the poor editor on BBC’s news programme “Breakfast” (11 jan 2011) subtitling, as Professor Robert Winston and others discussed the possibility of gender selection to "complete your family in the way you desire" i.e. to finally achieve that longed for girl or boy.
Throughout the discussion the text editor had kept up admirably, coping with explanations of these gender selection techniques:
- at fertilisation (by enriching for male sperm)
- pre-implantation (by removing a cell from a fertilised embryo to check the sex.
(Both techniques are tried and tested. Sperm enrichment is used for cattle breeding and pre-implantation tests are used to select healthy embryos without a gender-linked genetic defect)
In vivo fertilisation was rendered accurately too, which just shows how much the public has come to know and understand about IVF since it was first introduced all those years ago.
Then Professor Winston mentioned in passing “epigenetic influences” which was transcribed rapidly onto my TV screen as “EDGE THE GENETIC”!
Clearly the editor hadn’t a clue. So I’ve decided to define (& explain) for you the term “epigenetic” so that you will. Along the way, I hope, you emerge fascinated…