More on rice shortages
Thais hold key to rice shortages
http://news.bbc.co.uk/2/hi/asia-pacific/7222043.stm

selil I think the term you were looking for is mono-culture and in the perpetual war between pathogens and our food crops the pathogens will always adapt faster (this is an inevitable result of the differences in their evolutionary genetic strategy). Loss of bio-diversity is a major long term problem and concern regarding pandemics not misplaced. The widespread use of infertile hybrids and genetic modification of food species giving improved yields will aggravate the problem as they promote a further curtailing in genetic diversity (only in the food crop not in the pathogen).