CANBERRA, Sept 27 AAP - Global crop yields must soar in coming years orthe world will face a grain shortage, one of the world's leading grainsexperts warned today.

Professor Monkombu Swaminathan, one of the pioneers of the greenrevolution and a winner of the World Food Prize, told a crop conference inBrisbane that the world was going through a major decline in yieldimprovements. And he said all forms of technology, including conventionalbreeding and genetic modification, would be needed to address apotentially devastating drop off in crop yields.

Around 1,000 crop scientists from across the globe have gathered inBrisbane this week to discuss the fate of cropping, from Australia's wheatcrops to beetroot and exotic fruits. Prof Swaminathan said crop yield, therate of production per hectare, had grown strongly through much of the20th century on the back of scientific breakthroughs, new breeds and theadvent of improved farming systems. But yield improvements were nowslipping to the point that production of major crops may not be able tomeet demand in coming years. He said degradation of the environment,spreading cities that devoured cropping land, huge population increasesand increasing wealth all meant that demand for grains and cereals wasgrowing strongly. Without major improvements in crop yields, this would gounmet.

"Crop yield simply must continue to grow in order to meet this demand, aswell as to counter arable land losses from degradation and urbanisation,"he said. Prof Swaminathan said research had to be poured into boostingcrop yields. He said although there was some consumer resistance,particularly in the western world, to genetically modified crops they hadto be considered as part of the solution. No technology should be rejectedin the pursuit of new ways of lifting crop production.

"Investment in successful science like conventional breeding and agronomyand agricultural extension cannot be lessened, but nor can newtechnological possibilities be ignored or pursued in isolation from theconventional," he said. "Besides the farmer cannot be overlooked in thisprocess, not the broader public who will largely pay for and benefits fromthis crop science."

Prof Swaminathan said a return to the distant past is already helpingfarmers in some countries. He said reduced tillage, in some cases bysimply using a stick to poke a hole in the soil and then depositing aseed, was one way of saving soils to boost productivity. "In a sense weare returning to Neolithic farming where human effort planted the earlycrops with little soil disturbance," he said.