Development and characterization of the 4th CSISA-spot blotch nursery of bread wheat Pawan K. Singh & Yong Zhang & Xinyao He & Ravi P. Singh & Ramesh Chand & Vinod K. Mishra & Paritosh K. Malaker & Mostofa A. Reza & Mokhlesur M. Rahman & Rabiul Islam & Apurba K. Chowdhury & Prateek M. Bhattacharya & Ishwar K. Kalappanavar & José Crossa & Arun K. Joshi Accepted: 10 July 2015 /Published online: 19 July 2015 # Koninklijke Nederlandse Planteziektenkundige Vereniging 2015 Abstract Spot blotch (SB) caused by Cochliobolus sativus is a serious biotic stress to wheat in warm and humid areas, particularly South Asia (SA). In order to support South Asian farmers to combat SB, International Maize and Wheat Improvement Center (CIMMYT) established an efficient SB screening sys- tem at Agua Fria, Mexico and developed a nursery under the project - Cereal Systems Initiative for South Asia (CSISA). The materials used to form CSISA-SB nursery were selected from advanced breeding lines from different wheat breeding programs at CIMMYT. Seed of CSISA-SB nursery was produced at disease- free plots at El Batan and Mexicali, and distributed to SA after rigorous seed health checks. The 4th CSISA- SB, made available in 2012, comprised 50 entries in- cluding two resistant and two susceptible checks. The nursery was evaluated in seven locations in Mexico, India, and Bangladesh in the 2012–13 cropping season. The results indicated that although few lines exhibited stable resistance across locations due to strong G × E interaction, promising lines with SB resistance and good agronomy can still be identified in each location. The two most promising lines showing consistent spot blotch resistance across the regions were CHUKUI#1 (CIMMYT germplasm bank identification number, GID 6178575) and VAYI#1 (GID 6279248). These lines Eur J Plant Pathol (2015) 143:595–605 DOI 10.1007/s10658-015-0712-x Electronic supplementary material The online version of this article (doi:10.1007/s10658-015-0712-x) contains supplementary material, which is available to authorized users. P. K. Singh (*) : Y. Zhang : X. He : R. P. Singh : J. Crossa International Maize and Wheat Improvemnet Center (CIMMYT), Apdo. Postal 6-641, 06600 Mexico, DF, Mexico e-mail: pk.singh@cgiar.org Y. Zhang Lixiahe Region Institute of Agricultural Sciences of Jiangsu Province, Yangzhou 225007, China R. Chand : V. K. Mishra : A. K. Joshi Department of Genetics and Plant Breeding, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, India P. K. Malaker : M. A. Reza Wheat Research Centre, Bangladesh Agricultural Research Institute, NashipurDinajpur, Bangladesh M. M. Rahman Regional Agricultural Research Station, Bangladesh Agricultural Research Institute, Jamalpur, Bangladesh R. Islam Regional Agricultural Research Station, Bangladesh Agricultural Research Institute, Jessore, Bangladesh A. K. Chowdhury : P. M. Bhattacharya Department of Plant Pathology, Uttar Banga Krishi Vishwa Vidyalaya, Coochbehar, W. Bengal, Indiax I. K. Kalappanavar Dr. Sanjaya Rajaram Wheat Laboratory, University of Agricultural Sciences, Dharwad, Karnataka, India A. K. Joshi CIMMYT South Asia Regional Office, Kathmandu, Nepal