US agency sets sights on grass in bid to make a better biofuel

Arpa-E project deploys drones and robots to breed fast-growing, drought-resistant and greener biofuel from sorghum which could replace corn ethanol

A US government agency is trying to build a better biofuel, using a higher energy-producing plant with a lower environmental impact than corn ethanol or other known biofuels.

Sorghum, a food and forage crop widely grown in Africa and Central America which has tens of thousands of varieties, has emerged as one of the most exciting prospects.