Day-glo potato will use genes from jellyfish

THE 21ST-CENTURY farmer could grow "smart plants" such as fluorescent potatoes and glowing wheat to decide when a field needs watering or fertiliser. He could also be driving farming equipment on paths determined by satellites orbiting the Earth.

And fewer people will work on farms, which will increase in size through conglomeration of smallholdings, scientists at the conference said yesterday.

"Smart plants" are already being planned, incorporatingjellyfish genes. A team at the Edinburgh University intends to produce genetically modified potatoes which would glow to indicate they need water. "They would be sentinels in a field," said Ann Haley, one of the researchers. "The technology is there."

With potatoes, providing the right amount of water and avoiding dehydration can triple yields. The sentinel plants would be harvested first, so they would not be eaten. The technology could be applied to almost any plant which can be genetically modified, and used to indicate a wide range of plant "stresses". Researchers are also developing "precision agriculture" using global positioning system (GPS) satellite technology to spray herbicides and plough fields more accurately

"Every field varies - soil type and moisture, slope, tree shade," said John Stafford of the Silsoe Research Institute. "Farmers had to just apply herbicide uniformly, though weed distribution might be patchy, and dig seeds at the same depth, which produces a seed bed of uneven quality."

The solution is to vary spraying and digging according to a detailed map of the field, but that requires precise positioning of machines. Using GPS, "we can target themright down to the square metre," said Mr Stafford.

Potential savings are huge. The four million hectares of arable land in England and Wales each year use 1.6 million tonnes of nitrogenous fertiliser and 21.6 million kilos of agrochemicals, including 11.6 million kilos of herbicide.