ORIGINAL PAPER Effect of waterlogging at different growth stages on some morphological traits of wheat varieties Mohammad Eghbal Ghobadi 1 & Mokhtar Ghobadi 1 & Alireza Zebarjadi 1 Received: 25 April 2016 /Revised: 18 August 2016 /Accepted: 20 August 2016 # ISB 2016 Abstract Excess rainfalls may be the cause of waterlogging in soil, which affects the growth and development of wheat. Therefore, the objectives of this study were to examine the effects of waterlogging on shoot and root growth and physiological characteristics of wheat. Three experiments were conducted: ex- periment 1 (E1): evaluation of seedling growth on ten Iranian winter wheat varieties with waterlogging periods (1–4, 4–8, 8– 12, and 12–16 days starting from seed germination). Seminal roots and plumule were investigated at seedling. The others are E2: pretreatment of waterlogging (15 days) at tillering and stem elongation stages and its effects on shoot and root growth at anthesis stage and experiment 3 (E3): pretreatment of waterlogging (15 days) at tillering and jointing stages and its effects on yield and yield components and also evaluation of stress tolerance indexes. The results of the seedling growth test (E1) showed that 1–4- and 4–8-day waterlogging severity re- duced seminal root length (94.5 to 93.7 %) and plumule length (86.2 to 50.0 %) compared to control. Results of E2 indicated that waterlogging stress decreased shoot dry weight, root dry weight, total secondary root length, and chlorophyll a + b content of flag leaf by 28–31, 44–35, 20–31, and 28–35 %, respectively. Also, result of E3 showed that the grain yields of wheat varieties at two conditions of stress were different in base tolerance index- es. In general, the responses of wheat varieties to waterlogging were different at the three experiments. The varieties that had the most of dry weight and length of the root were tolerant. Thus, it is possible to use these characteristics as an index for selecting the varieties with tolerance to waterlogging. Keywords Waterlogging . Wheat . Root and shoot growth . Tolerance indexes . Yield and yield components Introduction Noteworthy areas of arable land in the world are exposed to waterlogging or flooding. Soil waterlogging is common in areas that have high rain intensity. Other factors, including heavy texture (clay) soil, low slopes, and poorly drained soils, also contribute to flooding, even in drought regions (Alam and Rabbani 2007; Dickin and Wright 2008 Setter et al. 2009). During waterlogging, the gas exchange decreases between soil and air. In this condition, oxygen in the soil is depleted rapidly, and the soil may become hypoxic (low oxygen) or anoxic (no oxygen) within a day (Araki et al. 2012b; Armstrong et al. 2009). Lack of soil oxygen can limit plant yield directly by altering root metabolism or indirectly by changing plant nutrient availability (Bailey-Serres et al. 2012; Setter et al. 2009; Zhang et al. 2011). Oxygen is needed to produce energy for growth during the breakdown of organic compounds. When the oxygen is depleted in soil, the roots and aerobic microorganisms lose almost all capacities to produce energy; therefore, they stop growing and may die (Ahsan et al. 2007; Armstrong et al. 2009; Licausi and Perata 2009; Sauter 2013). Waterlogging can produce an effect on several physiological processes such as absorption of water and root and shoot hor- mone relations (Jackson 2008; Licausi and Perata 2009) and decrease the uptake and transport of ions through roots causing nutrient deficits; element toxicities such as Mn, Fe, Na, Al, and B (Setter et al. 2009 Zhang et al. 2011); and activities of superoxide dismutase (Huang et al. 2015; Simova-Stoilova et al. 2012). Waterlogging or flooding reduces shoot and root growth and final yield (Jackson and Colmer 2005; Romina et al. 2014; Tiryakioglu et al. 2015). Waterlogging tolerance in plants is * Mohammad Eghbal Ghobadi eghbalghobadi@yahoo.com 1 Razi University, Kermanshah, Iran Int J Biometeorol DOI 10.1007/s00484-016-1240-x