CROPS AND SOILS RESEARCH PAPER Wheat seedlings growth response to water deficiency and how it correlates with adult plant tolerance to drought D. DODIG 1 *, M. ZORIC ´ 2 , M. JOVIC ´ 3 , V. KANDIC ´ 1 , R. STANISAVLJEVIC ´ 4 AND G. Š URLAN-MOMIROVIC ´ 5 1 Maize Research Institute, ‘Zemun Polje’, Slobodana Bajic ´ a 1, 11185 Belgrade, Serbia 2 Institute of Field and Vegetable Crops, Maksima Gorkog 30, Novi Sad 21000, Serbia 3 Center for Agricultural and Technological Research, Zajecar, Grljanski put bb, 19000 Zajecar, Serbia 4 Institute for Plant Protection and Environment, Teodora Drajzera 9, 11000 Belgrade, Serbia 5 Institute of Field Crop Science, Faculty of Agriculture, University of Belgrade, Nemanjina 6, 11080 Belgrade, Serbia (Received 22 April 2013; revised 7 October 2013; accepted 24 March 2014; first published online 25 April 2014) SUMMARY Improving resistance to water and osmotic stresses at the seedling stage is becoming a much more important target for wheat breeders due to an increase in the frequency and severity of drought occurrences at the crop establishment and tillering phases in many wheat growing areas of the world. Ninety-six diverse wheat genotypes were laboratory tested for germination and growth response under osmotic stress induced by polyethylene glycol (PEG). Germination percentage, mean germination time, coleoptile length, shoot length and shoot growth rate were compared under stress (- 0·4 MPa) and control (0·0 MPa) conditions. The same genotypes were previously grown in field trials exposed to drought stress during the anthesis and/or grain filling growth stage along with control (optimum) conditions. Grain yield (GY) and 19 other traits of agronomic importance (earliness, stem- related traits, number of kernels, mass of 1000 grains, etc.) were recorded. All seedling traits under PEG-induced water stress showed the highest relationship with the stem and stem-related traits of adult plants. To study the correlation between stress tolerance in the seedling and reproductive stages, three stress indices (tolerance index (TOL), stress susceptibility index (SSI) and stress tolerance index (STI)) for the seedling traits and GY under pre- and post-anthesis drought stress were calculated, based on a mean trait value obtained under stress and the corresponding trait value under control conditions. The ranking of the genotypes based on TOL and STI from seedling traits was found in most cases to be significantly correlated with the ranking of genotypes based on TOL and STI from GY, respectively. INTRODUCTION The main factors currently limiting the world’s crop production are osmotically challenged conditions such as drought and soil salinity. Water resources are limited in most of the countries around the eastern and southern Mediterranean (Parry et al. 2005) and in many other parts of Africa and Asia (FAO 2003) as well as Australia (Chapman 2008). Some estimates indicate that half of the total global area of wheat sown annually is affected regularly by drought (Pfeiffer et al. 2005). The reduction of wheat yield, depending on time and intensity of drought and also additional kinds of biotic and abiotic stresses, varies from 10 to 90% of its potential yield under non-stressed conditions (Reynolds et al. 2005). Three stages in wheat growth are particularly sensitive to the effects of water deficiency, namely seedling establishment, booting and grain filling (Fischer & Turner 1978). The last of these stages, being at the end of the season, is usually accompanied by damaging high temperatures during the summer months. If soil has insufficient moisture at the time of sowing then germination and seedling establishment will be poor, leading to fewer plants per unit area with smaller growth potential. Drought at meiosis * To whom all correspondence should be addressed. Email: ddodig@mrizp.rs Journal of Agricultural Science (2015), 153, 466–480. © Cambridge University Press 2014 doi:10.1017/S002185961400029X