Drought-hardy bean touted as solution to food security

Drought-prone regions around the world could benefit from a climate resilient bean to bolster food security, scientists have said.

The hyacinth bean or lablab bean native to Africa and cultivated throughout the tropics producing highly nutritious beans, which are used for food and livestock feed, has shown capacity for different adaptive genotypes for different environments and climatic challenges.

Researchers have sequenced the bean paving the way for its wider cultivation across the globe.

In a study published in Nature Communications in April, the scientists said it is drought-resilient and thrives in a range of environments and conditions, contributing to food and economic security, and improving soil fertility by fixing nitrogen.

Lablab is also used medicinally as it contains bioactive compounds with pharmacological potential.

Also known as Rongai dolichos, or poor man’s bean, it is a multipurpose legume since its immature seeds and pods, and young leaves are edible and cooked as vegetables.

Research shows the bean’s genetic diversity also holds clues for widespread climate smart agriculture and could unlock the broad genetic variations which may substantially contribute to future plant improvement.

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According to Associate Professor at the University of Southampton, Mark Chapman, “This opens the door to studying whether agronomic traits can evolve more than once using the same genes, or if different pathways can evolve to give the same outcome.”

In the wild, lablab is found in grassland and bushland. As a cultivated crop, lablab has many favourable traits such as its ability to grow in a diverse range of environmental conditions.

Dry season

It is a summer growing legume that remains green during the dry season when other fodder is scarce and dry.

Lablab withstands high temperatures and grows where daily temperatures are in the range of 18-35 degrees Celsius, and thrives in full sunlight and where annual rainfall is between 650mm and 2,500-3,000mm.

Thanks to its taproot, the drought-tolerant bean can extract water from two meters below the soil surface, which makes it drought hardy and allows it to grow during the dry periods of the year.

It can also tolerate some flooding but does not withstand poor drainage or prolonged waterlogging. It also thrives in a wide range of soils.
The lablab bean is one of a long list of ‘orphan crops’ indigenous species that play an important role in local nutrition and livelihoods, but that receive little attention from breeders and researchers.

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Underutilised crops like lablab hold the key to diversified and climate-resilient food systems, and genome-assisted breeding is one promising strategy to improve their productivity and adoption.

“The plant’s adaptability suggests high genetic diversity, which means it’s possible to select different adaptive genotypes for different environments and climatic challenges.

ut lablab’s potential for genetic improvement to boost its productivity and facilitate wider cultivation – especially in drought-prone areas – has yet to be fully exploited,” explained Chris Jones, programme leader for Feed and Forage Development at the International Livestock Research Institute (ILRI).

“When it comes to valuing a crop, people often focus on its global market value in dollars,” said Jones.

“However, for farmers who struggle to produce enough food, the value of a crop like lablab is incredibly high. Although it may be cultivated on a smaller scale compared with major crops, its impact on food security can be significant, and we need to recognise that,” he added.