Contents lists available at ScienceDirect Agricultural and Forest Meteorology journal homepage: www.elsevier.com/locate/agrformet Identifying optimal sowing and flowering periods for barley in Australia: a modelling approach Ke Liu a,b , Matthew Tom Harrison b, ⁎ , James Hunt c , Tefera Tolera Angessa d , Holger Meinke b , Chengdao Li d , Xiaohai Tian a , Meixue Zhou a,b a Hubei Collaborative Innovation Center for Grain Industry/School of Agriculture, Yangtze University, Jingzhou, China b Tasmanian Institute of Agriculture, University of Tasmania , Tasmania 7320, Australia c Department of Animal, Plant and Soil Sciences, La Trobe University, Bundoora, Victoria 3086, Australia d Western Barley Genetics Alliance, School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA, Australia ARTICLE INFO Keywords: Breeding Deterministic modelling Drought Climate Anthesis Frost Heat ABSTRACT Frost, drought and heat are key abiotic constraints to barley production in Australia. To maximise grain yield, crop life-cycle needs to be timed to minimise growth stresses associated with insufficient radiation, frost, heat and drought stress during the critical period for yield determination that occurs prior to and during flowering. To identify optimal flowering times for commercial Australian barley genotypes, we conducted a genotype (G) × environment (E) × management (M) analysis using climate data from locations distributed throughout the Australian barley growing regions. Prior to conducting the G×E×M, we parameterised key phenological variables in the APSIM-Barley module for all genotypes using photoperiod and vernalisation data from experi- mental treatments, then we verified the model using seven independent field experiments. The verification process showed an average RMSE of 1.4–7.2 days and R 2 values of 0.83–1.00 depending on genotype, indicating reasonable performance of the model in simulating phenology. Using the parameterised model, we then char- acterised water, frost and heat stress patterns for a range of sowing date × genotype combinations. The G×E×M showed that optimal flowering period (OFP) was a function of the environment more so than the genotype, and the relative importance of insufficient radiation, frost, heat and water stress varied signficantly with location. OFP was earlier (mid August to late September), in Western Australia and South Australia, while OFP was later (mid-October to mid-November) in Tasmania and Victoria. In low rainfall environments, the duration of the OFP was shorter in most cases than in high rainfall environments. In general, earlier sowing (1 April to 22 April) resulted in lower yield across sites, and this was more pronounced for fast developing gen- otypes La Trobe, Fathom, Compass and Alestar. Later sowing (1 June to 30 June) at Condobolin (NSW), Hopetoun (WA) and Loxton (SA) also resulted in a lower yield for all genotypes. Knowledge of OFPs based on long-term abiotic stresses will allow breeders to develop genotypes with phenological durations that are perti- nent to each location. This will also allow farmers to select sowing dates according to genotype duration and thus minimise the combined risk of frost, heat and water stresses, which collectively should allow yield to approach its maximum potential. 1. Introduction Barley (Hordeum vulgare) is the second-largest cereal crop in Australia after wheat (Triticum aestivium), and on average is grown on almost four million hectares from Western Australia across to the eastern seaboard. Although barley is grown in many environments, there are several factors which reduce potential yield. In Australia, barley foliar diseases (e.g. net blotches, scald, barley leaf rust etc.) are some of the major biotic stress factors attributed to yield and quality losses (Angessa and Li., 2016). The main abiotic stress factors of barley production in Australia are water stress coupled with heat stress during spring and summer, and frost events in winter and early spring. It is these stresses during the critical period for yield determination, which occurs in barley just prior to anthesis (Arisnabarreta and Miralles, 2008), which can cause severe yield reductions (Barlow et al., 2015; Hossain et al., 2012; Murray et al., 2010). In Australian barley cropping regions, spring and winter barley genotypes are generally sown in autumn, grow through the winter, flower in early spring, and https://doi.org/10.1016/j.agrformet.2019.107871 Received 21 August 2019; Received in revised form 10 December 2019; Accepted 10 December 2019 ⁎ Corresponding author. E-mail address: matthew.harrison@utas.edu.au (M.T. Harrison). Agricultural and Forest Meteorology 282–283 (2020) 107871 0168-1923/ © 2019 Elsevier B.V. All rights reserved. T