Why we need to expand our crop menu

Names are steeped in meaning in Uganda. They reflect parents' hopes and aspirations for their children, as well as ties to their culture and environment.

Traditionally, among the Banyoro and Batooro communities in western Uganda, clan members hold special ceremonies when they bestow a name to a baby. At these ceremonies, known as okuruka amabara, villagers examine the baby for family features and distinctive qualities in order to pick the name befitting what they believe is the child's character.

Towards the climax of the naming ritual, those present are given millet bread, served fresh from the fire in wicker baskets called endiiro, alongside pots of steaming smoked beef or pigeon peas and peanut butter stew. The fresh millet bread is also a signifier of the change of season, releasing a scent like that of clean air and rain falling on dry ground.

Historically, every family would cultivate their own plot of millet and harvesting the crop was a communal activity. Towards the harvest season, children would patrol millet fields, banging empty tins with sticks to scare away the insatiable quelea birds. Then in November and December, groups of women armed with baskets and knives would harvest millet. Wooden granaries, raised off the ground on stilts close to the homes, would heave with the grain by Christmas.

But millet, a major crop in both Africa and Asia and one of the world's most nutritious cereals, is now under threat. Production is decreasing and many families have flattened the wooden granaries where they used to store the crop, using them as firewood. A dish of millet bread and pigeon peas-groundnut stew is no longer a common traditional meal in many households. 

Nearly one million plant and animal species are threatened with extinction, including the closely related wild relatives of domesticated crops such as maize, avocado, common bean, cotton, potato, vanilla, chilli pepper, squash and husk tomato.

The loss of wild varieties represents a grave risk to global food security, as they are a key source of genetic diversity, which can be used to reintroduce desirable traits such as drought and disease resistance to crops through breeding. According to the Royal Botanic Gardens at Kew, UK, we now rely on just 15 crops for 90% of the world's energy intake

In Uganda, the wet and dry seasons are becoming more intense and lasting longer, while human lives and crops are now lost to floods nearly every year. Erratic rains and floods have led to the failure of pearl millet at various times – the world's most common millet type. 

When it comes to finger millet – the most popular type in Uganda, Kenya and Tanzania – excessive rains result in poor germination, while severe drought can lead to total crop failure. Pigeon pea crops are also experiencing significant yield loss as heat stress disrupts the bloom stage by damaging the pods. 

"Seasons have changed [so much] that we now have rain at Christmas, which was not the case in the 1990s, when it used to be a dry season," says Byakagaba. "It's around this time that people harvest millet. Due to losses from rains, farmers have abandoned millet. Excessive rain is responsible for high rates of abandonment in crops."

In Kenya, traditional crops like yam, cassava, sweet potato and pumpkin have slowly disappeared from the diets of many households. "We have lost them as cultural foods. They used to feature a lot previously," says Wanjira Mathai, regional Africa director at the World Resources Institute.

Kenyan farmers have suffered successive drops in yields of crops like millet, dolichos lablab bean and pigeon pea due to climate change, according to the Kenya Climate Change Working Group (KCCWG) and Women's Climate Centers International. "These are the traditional crops which were suitable in these semi-arid areas and contributed to food security and incomes," says KCCWG's chairman, John Kioli. 

There are over 2,000 overlooked native grains and fruits in Africa, including finger millet, African rice, pearl millet and sorghum, which constitute a huge food resource for the growing population. 

For farmers battling falling millet yields from dry spells, irrigation holds part of the answer. For instance, the average millet yield on dry lands is 1.8 tonnes per hectare (0.73 tonnes per acre) in Uganda and one tonne per hectare (0.4 tonnes per acre) in India. But on irrigated lands, yields can go up to six tonnes per hectare.

Increasing yields of traditional crops is part of the agenda at the Kenya Agricultural and Livestock Research Organisation. Here, researchers have developed six improved varieties of finger and pearl millet adapted to varying climate conditions and different soil types.

The three pearl millet varieties, which are said to be high-yielding, coupled with a recently approved genetically modified cassava variety, are part of Kenya's efforts to combat food insecurity. On top of these, the Kenyan researchers have developed four drought-resistant sorghum varieties which mature within two to three months of planting.

Some of these crops, such as pearl and finger millet, are descended from grasses in Africa that were domesticated thousands of years ago. The modern varieties could borrow genes for tolerance to heat, cold, drought, water logging and the ability to mobilise nutrients from their wild relatives.

It is an approach that will be necessary to ensure the survival of a wide range of crops – some of which are hugely important commodities at the centre of global industries.

Researchers hope to retain genetic diversity by preserving natural habitats where wild varieties and landraces thrive. But, as an insurance policy, genetic materials can also be conserved outside the natural environment in seed banks.

Gayle Volk, a research plant physiologist at the National Laboratory for Genetic Research Preservation (NLGRP), a US seed bank with 550,000 samples, says the diverse genetic resources held in the facility are accessible to breeders and researchers. 

But not all crops can be kept in seed banks, which means we need alternatives, too. Wild coffee plants, already threatened with extinction, cannot be preserved indefinitely in a cold, dry facility – which is how seeds are stored at the bank. Nevertheless, there's another way of conserving coffee – cryopreservation, an ideal method for preserving plants with limited seed storage capability. 

Ashley Shepherd, a lab technician at NLGRP, explains that shoot tips are harvested from coffee plants and frozen in liquid nitrogen, halting the metabolic processes.

Technology can help to preserve genetic material, but we also need to use a greater variety of crops in the field. Traditional crops like millet – once so important in parts of Africa – are often overlooked in Western diets (though millet is predicted to increase in demand in Europe over the next few years).

Even if the granary where Businge used to keep millet all year round is no more and the crop's traditional function and naming custom are coming under greater threat than ever before, he hopes that one day millet will get the same research attention as crops like rice and maize. 

"Millet has been a major source of food for our family and a key part of our traditions like naming for many years," he says. "Losing millet is not only loss of traditional food, but some of our customs as well. My family will continue to grow it for its unique traditional and nutritional benefits regardless of the reducing yields."

For now, Businge will rely on his traditional hand-hoe farming tool to grow the crop in the hope that his worn out land will continue to yield this delicious and nutritious grain so it doesn't become a thing of the past in his family.