Effect of salt stress during early seedling growth on phenology and yield of spring wheat

Abstract

Grain yield potential of wheat (Triticum aestivum L.) can be markedly affected by environmental stresses that occur early in the life cycle of the crop. This study was conducted in greenhouse sand cultures to determine the effects of salinity either applied or withdrawn at three different stages of wheat shoot organogenesis: (1) late in the leaf primordium initiation phase (LLPI), (2) double ridge stage (DRS), or (3) terminal spikelet formation (TSF). Plant response to changes in salinity was evaluated in terms of mainstem phenology, timing of tiller appearance, yield, and yield components. Leaf primordium initiation was more sensitive to changes in salinity than was spikelet primordium initiation. For changes in salinity at LLPI, final mainstem leaf number was controlled by the new, rather than the original, stress level, whereas when salinity was changed at DRS, final spikelet number was controlled by the original salinity level. Changes in salinity level did not inhibit tiller bud initiation, but affected the timing of tiller emergence. Grain yields were reduced by relatively brief periods of salinity, but losses were minimized if stress was withdrawn at LLPI or DRS or if stress application was delayed until TSF.