EFFECT OF WATER SHORTAGE ON MAIN SHOOT DEVELOPMENT AND TILLERING OF COMMON AND SPELT WHEAT

Water stress was imposed by cessation of watering (CW) on bread wheats and, in some experiments two spelt wheats, during 9-17 days, starting at the 4-5 leaves stage. Main shoot foliar stages (MSS) were delayed by CW and the effect remained thereafter. The presence of side tillers (intact or partly destroyed by heat or potassium iodide (KI) was not beneficial to main shoot foliar development after the end of CW. Emerg ence of tillers after the onset of CW was also delayed, but the effect was small if timing was expressed in MSS. Secondary tillers were the most sensitive to water shortage, their number, size and foliar stage were drastically reduced. The two cultivars of spelt wheats were not l ess sensitive to CW than the bread wheat tested.