Multiple heat and drought events affect grain yield and accumulations of high molecular weight glutenin subunits and glutenin macropolymers in wheat

Spring wheat plants were subjected to water deficit and/or high temperature episodes at spikelet initiation, anthesis or both stages. The stresses modified the early dough stage and maturity, shortened the kernel desiccation period and caused grain yield loss. Plants subjected to stress at the early growth stages had higher grain yields than the non-early-stressed plants when stress reoccurred at anthesis. Concentrations of high molecular weight glutenin subunits in grain were up-regulated by the single early drought, the early drought combined with late heat and the double drought stress treatments, but was down-regulated by the early heat and double heat stress events. Concentration of glutenin macropolymers 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 stress, but was reduced by the early heat stress and double heat events.

► Multiple heat and drought shorten kernel desiccation period and reduce wheat yield.
► Multiple heat and drought modify HMW-GS and GMP formation in grain.
► Early drought alleviates the damage to grain quality by late drought and heat stress.