OVERWINTERING OF WINTER CEREALS IN HUNGARY IN THE CASE OF GLOBAL WARMING

Under phytotronic conditions investigations were made on the effect of important environmental factors, such as temperature, water and an in creasing concentration of atmospheric CO2, on the hardening of young c ereal plants. In all the varieties derived from the major wheat growin g regions of the world the hardening process was favourably influenced by a doubling of atmospheric CO2 content, so that a significantly lar ger number of plants survived the frost test than for plants of the sa me variety raised under normal conditions. A reduction in freezing tem perature and an increase in soil moisture content caused a slight redu ction in survival % for varieties with excellent frost resistance and a great reduction for those with medium or poor frost resistance. Pred ictions suggest that in Central Europe, as the result of global climat ic changes, there will be a reduction in the quantity of winter precip itation, a considerable rise in winter temperatures and an increase in atmospheric CO2 concentration. Judging by the experimental results, t hese changes could improve the overwintering of winter cereals; at the same time, however, a number of factors (mainly the reduction of prec ipitation) leading to yield losses must be expected during the vegetat ion period.