Spring wheat plants were subjected to water deficits and / or high temperature episodes at spikelet initiation,anthesis or both stages.The stresses modified the early dough stage and maturity,shortened the kemel desiccation period,and caused loss of grain yield.Plants subjected to stress at the early growth stages had higher grain yields when stressed again at anthesis.Concentrations of high molecular weight glutenin subunits (HMW-GS) in the grain was up-regulated by the single early drought event,the early drought combined with late heat stress and the double drought stresses,but was down-regulated by the early heat and double heat stresses.Concentration of glutenin macropolymer (GMP) was increased by the single early drought episode,the single late drought and heat events,as well as the early drought combined with the late heat stresses,but was reduced by the early heat and double heat stresses.The results of the effect of various stress combinations are discussed in relation to the changes in concentrations of HMW-GS in grain and the modified growth periods under different stress combinations.