Changes in the Abiotic Stress Tolerance of Wheat as a Result of an Increased Atmospheric CO2Concentration

Abstract

Climatic change, a global environmental problem particularly affecting agriculture and the natural environment, is now seen to be associated with an increase in the frequency and intensity of climatic anomalies. Weather extremes in Hungary have included droughts in the 1980s, hot, dry summers in 2001-2003, and excessive rainfall in 2004 and 2005 Research on the effect of climate extremes on the biomass, yield and abiotic stress tolerance of wheat has been done in the phytotron of the Agricultural Research Institute in Martonvasar. Studies on the frost resistance, heat tolerance and drought tolerance of wheat varieties with various genetic backgrounds were made when grown under normal and increased atmospheric CO2 concentrations and at various nutrient supply levels. The following conclusions were drawn from the results\rThe frost resistance of wheat grown and cold-hardened at double the current level of atmospheric CO, concentration improved to various extents; this effect was more pronounced in frost-sensitive genotypes\rHeat stress had severe effects: it decreased biomass accumulation and the thousand kernel weight, resulting in a yield loss of between 27% and 37%. Increased CO, concentration was able to counteract the deleterious effects of the heat stress\rWhen plants were exposed to heat stress, the yield loss was lower at low nitrogen levels\rDepending on the genotype the yield quality deteriorated to various extents in heat-stressed plants at doubled CO2 concentration\rThe doubled CO2 concentration was able to reduce the deleterious effects of drought stress on yield components\rIt can be seen from the results that genetic differences among winter wheat varieties can allow breeders to select genotypes with better adaptability, enabling them to be grown reliably even under altered environmental conditions.