The effect of different levels and stages of low irrigation on some morphological traits of amaranth cv. Koniz (Amaranthus hypochindriacus L.× Amaranthus hybridus L.)

Drought is one of the most stressful environmental factors that strongly influence the growth and yield of crops. However, the plant’s response to this stress differs depending on the stage of its growth. The present study set out to investigate the effect of different levels of low irrigation regimes (irrigation after 50, 80, 110, 140 and 170 mm evaporation from pan A) in different growth stages (plant establishment, branching, flowering and grain filling). The results of the study showed that irrigation after 170 mm evaporation of pan following the plant establishment, branching, flowering and grain filling, caused biomass reduction by 8%, 27%, 43% and 53%, respectively. Irrigation levels after 80, 110, 140 and 170 mm evaporation from pan led to the reduction of yield by 12%, 22%, 33% and 45% compared to the irrigation after 50 mm evaporation from the pan. In case of stress per delay time of irrigation based on evaporation from the evaporation pan, the grain yield decreased by 3.03 units. Results showed that applying low levels of irrigation before pollination leads to further reduction of the yield; so that the stress in the stages of plant establishment, branching, and flowering reduced the yield by 34, 27 and 22% compared to the irrigation after 50 mm evaporation from pan.