RESEARCH ARTICLE Radiation efficiency and nitrogen fertilizer impacts on sunflower crop in contrasting environments of Punjab, Pakistan Wajid Nasim 1,2,3 & Ashfaq Ahmad 4 & Asad Amin 1 & Muhammad Tariq 5 & Muhammad Awais 6 & Muhammad Saqib 6 & Khawar Jabran 7 & Ghulam Mustafa Shah 1 & Syeda Refat Sultana 1 & Hafiz Mohkum Hammad 1 & Muhammad Ishaq Asif Rehmani 8 & Muhammad Zaffar Hashmi 9 & Muhammad Habib ur Rahman 10 & Veysel Turan 11 & Shah Fahad 12,13 & Shah Suad 14 & Aziz Khan 15 & Shahzad Ali 16 Received: 13 July 2017 /Accepted: 24 October 2017 # Springer-Verlag GmbH Germany 2017 Abstract Sunflower (Helianthus annuus L.) is the leading non-conventional oilseed crop in Pakistan. Nitrogen fertilizer can affect plant growth and productivity by changing canopy size which has an effect on the radiation use efficiency (RUE) of the crop. The response of sunflower hybrids in terms of phenology, fraction of intercepted radiation (F i ), and RUE to nitrogenous rates (0, 60, 120, 180, and 240 kg ha -1 ) was studied in three field experiments conducted in three various environments: Multan (arid), Faisalabad (semi-arid), and Gujranwala (sub-humid) during spring seasons 2008 and 2009. The treatments were laid out according to a randomized complete block design with split plot arrangements, keeping the sunflower hybrids in main plots and nitrogen rates in sub- plots, and replicated three times. The results showed Hysun- 38 took a maximum number of days to anthesis (101) as compared to Pioneer-64A93 (100) and Hysun-33 (99). The mean values of F i were 0.850, 0.903, and 0.978, and the esti- mated values of RUE for total aboveground dry matter were 2.14, 2.47, and 2.65 g MJ -1 at experimental locations of Multan, Faisalabad, and Gujranwala, respectively. The values Responsible editor: Philippe Garrigues * Wajid Nasim wajidnaseem2001@gmail.com * Shah Fahad shah.fahad@mail.hzau.edu.cn; shahfahad@uoswabi.edu.pk 1 Department of Environmental Sciences, COMSATS Institute of Information Technology (CIIT), Vehari, Pakistan 2 CIHEAM-Institut Agronomique Mediterraneen de Montpellier (IAMM), Montpellier, France 3 CSIRO Sustainable Ecosystems, National Research Flagship, Toowoomba, QLD 4350, Australia 4 US-Pakistan Center for Advanced Studies in Agriculture and Food Security (USPCAS-AFS), University of Agriculture, Faisalabad 38040, Pakistan 5 Agronomy Section, Central Cotton Research Institute (CCRI), Multan, Pakistan 6 Department of Agronomy, University College of Agriculture and Environmental Sciences, The Islamia University of Bahawalpur Pakistan, Bahawalpur, Pakistan 7 Department of Plant Protection, Faculty of Agriculture and Natural Sciences, Düzce University, Düzce, Turkey 8 Department of Agronomy, Ghazi University, Dera Ghazi Khan, Pakistan 9 Department of Meteorology, COMSATS Institute of Information Technology, Islamabad, Pakistan 10 Department of Agronomy, MNS University of Agriculture, Multan, Pakistan 11 Department of Soil Science and Plant Nutrition, Division of Soil Microbiology, Faculty of Agriculture, Bingöl University, Bingöl, Turkey 12 College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China 13 Department of Agriculture, University of Swabi, Khyber Pakhtunkhwa, Pakistan 14 College of Horticulture, Northeast Agricultural University Harbin, Harbin, Heilongjiang 150030, China 15 Key Laboratory of Plant Genetic and Breeding, College of Agriculture, Guangxi University, Nanning, China 16 The Chinese Institute of Water-saving Agriculture, Northwest A&F University, Yangling, Shaanxi, China Environ Sci Pollut Res https://doi.org/10.1007/s11356-017-0592-z