title: Variation and impact of drought-stress patterns across upland rice target population of environments in Brazil.
abstract: The upland rice (UR) cropped area in Brazil has decreased in the last decade. Importantly, a portion of this decrease can be attributed to the current UR breeding programme strategy, according to which direct grain yield selection is targeted primarily to the most favourable areas. New strategies for more-efficient crop breeding under non-optimal conditions are needed for Brazil's UR regions. Such strategies should include a classification of spatio-temporal yield variations in environmental groups, as well as a determination of prevalent drought types and their characteristics (duration, intensity, phenological timing, and physiological effects) within those environmental groups. This study used a process-based crop model to support the Brazilian UR breeding programme in their efforts to adopt a new strategy that accounts for the varying range of environments where UR is currently cultivated. Crop simulations based on a commonly grown cultivar (BRS Primavera) and statistical analyses of simulated yield suggested that the target population of environments can be divided into three groups of environments: a highly favorable environment (HFE, 19% of area), a favorable environment (FE, 44%), and least favourable environment (LFE, 37%). Stress-free conditions dominated the HFE group (69% likelihood) and reproductive stress dominated the LFE group (68% likelihood), whereas reproductive and terminal drought stress were found to be almost equally likely to occur in the FE group. For the best and worst environments, we propose specific adaptation focused on the representative stress, while for the FE, wide adaptation to drought is suggested. 'Weighted selection' is also a possible strategy for the FE and LFE environment groups.
authors: Embrapa Rice & Beans Rodovia GO-462 km 12 Zona Rural, 75375-000 Santo Antônio de Goiás, GO, Brazil alexandre.heinemann@embrapa.br.
authors: Alexandre Bryan
authors: AB
authors: Heinemann
authors: International Center for Tropical Agriculture (CIAT), Km. 17 Recta Cali-Palmira A.A. 6713, Cali, Colombia.
authors: Camilo
authors: C
authors: Barrios-Perez
authors: International Center for Tropical Agriculture (CIAT), Km. 17 Recta Cali-Palmira A.A. 6713, Cali, Colombia CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS), Cali, Colombia School of Earth and Environment, University of Leeds, Leeds, UK.
authors: Julian
authors: J
authors: Ramirez-Villegas
authors: International Center for Tropical Agriculture (CIAT), Km. 17 Recta Cali-Palmira A.A. 6713, Cali, Colombia.
authors: David
authors: D
authors: Arango-Londoño
authors: International Center for Tropical Agriculture (CIAT), Km. 17 Recta Cali-Palmira A.A. 6713, Cali, Colombia CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS), Cali, Colombia.
authors: Osana
authors: O
authors: Bonilla-Findji
authors: Embrapa Rice & Beans Rodovia GO-462 km 12 Zona Rural, 75375-000 Santo Antônio de Goiás, GO, Brazil.
authors: João Carlos
authors: JC
authors: Medeiros
authors: International Center for Tropical Agriculture (CIAT), Km. 17 Recta Cali-Palmira A.A. 6713, Cali, Colombia CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS), Cali, Colombia.
authors: Andy
authors: A
authors: Jarvis
mesh_terms: D001938:Brazil; D002980:Climate; D003198:Computer Simulation; D018556:Crops, Agricultural / Q000502:physiology; D055864:Droughts; D004777:Environment; D005843:Geography; D012275:Oryza / Q000502:physiology*; D018526:Plant Transpiration; D013312:Stress, Physiological; D014867:Water
chemical_list: D014867:Water
keywords: Breeding; Oryza sativa; environment classification; modelling; water deficit.