In traditional plant breeding, some inbred maize plants destined to be crossed with others have their male, pollen-producing tassels cut off to prevent self-fertilisation (maize is a horticultural hermaphrodite, carrying both male and female sex organs).

ECONOMIST: Terminator genes

In the tropics, the higher temperatures could be expected to cut yields of the primary food crops, maize and rice, by 20-40%, the researchers said.

BBC: Heat may spark world food crisis

October's harvest is expected to produce only some 2m tonnes of grain, and that is assuming North Koreans do not try to cut the crops before they have fully ripened (maize output doubles in the last few weeks of the growing season).

ECONOMIST: Something on the table in North Korea