PEST CONTROL

Scientists release new, weed-resistant sorghum variety

It resists striga, a destructive parasitic weed that can cause up to 100 per cent yield loss.

In Summary

• The striga weed is a parasitic weed that has beautiful flowers. The weed attaches itself to roots of host crops such as maize, sorghum, millet, rice (mainly cereals) and it sucks out nutrients and kills the host crop.

• The weed causes up to 100 per cent yield loss and affects about 50 million hectares of African croplands, causing Sh1 trillion in crop loss annually.

The striga weed
The striga weed
Image: GOOGLE

Researchers have developed a sorghum variety that is resistant to the striga weed.

Prof Steven Runo, an associate professor at Kenyatta University, said the striga-smart sorghum has been developed through the modern technology of gene editing.

Gene editing is the use of naturally occurring molecular scissors to improve crops and animals' interaction with the environment for better traits such as weed resistance.

Speaking during a virtual media science café on the deployment of Striga Smart Sorghum in Kenya, Runo said science and technology have the potential to increase food productivity in Africa.

He said that Calestous Juma, the late Kenyan scientist and scholar, once said that weeds have done more harm to Africa than colonialism. This is because weeds always come back immediately after they are uprooted.

“One weed, in particular, is the striga weed, which is a parasitic weed that has beautiful flowers. The weed attaches itself to roots of host crops such as maize, sorghum, millet, rice (mainly cereals) and it sucks out nutrients and kills the host crop. The striga weed is a major threat to food security in sub-Saharan Africa,” said Runo.

He is from the Department of Biochemistry, Microbiology and Biotechnology.

According to the Kenya Agricultural and Livestock Research Organisation (Karlo) striga is a destructive parasitic weed that can cause up to 100 per cent yield loss.

It attacks the roots of staple crops such as maize, sorghum, millet, cowpea and upland rice. It affects about 50 million hectares of African croplands, causing Sh1 trillion in crop loss annually.

“In Kenya, the parasite is a serious pest that mainly threatens maize production with yield losses of between 65 and 100 per cent. With increasing demographic pressure and demand for food, there has been an intensification of land use, monocropping and consequently a decline in soil fertility. This depletion of soil fertility is one of the main causes for the increase in Striga incidence,” says Kalro report.

Runo said in order to address this challenge, scientists have developed the striga smart sorghum.

“Scientists collected samples of sorghum varieties grown in Africa that are resistant to the striga weed whose genome can be utilised for other important varieties but susceptible to the parasitic weed and then took that to the field and we explored the technic of genome editing. Genome editing is one of the modern tools that scientists can use to improve crop productivity,” he said.

He said the variety was tested in Busia, Kisumu and Homa Bay Counties where the weed is common.

“There is a lot of potential in agricultural technology and we need to harness it. African scientists must do this and must leverage partnerships with other countries to be able to use and harness technologies for crop improvement,” said Runo.