Acevedo, E. (1991). Improvement of winter cereal crops in Mediterranean environments. Use of yield, morphological and physiological traits. In Acevedo, E. (ed): physiology – breeding of winter cereals for stressed Mediterranean Enviroments. Le Colloque No. 55, pp 273 – 305, INRA, Paris
Addinsoft (2009). XLSTAT. France: Addinsoft. http://www.xlstat.com/en/products/xlstat-pls/
Anjum F, Yaseen M, Rasul E, Wahid A. and Anjum S. (2003). Water stress in barley (Hordeum vulgare L.). Pak. J. Agr. Sci. 40:45– 49
Badu-Apraku, B., Akinwale, R.O., Menkir, A., Fakorede, M.A.B. and Oyekunle, M.,(2011). Relationships among traits of tropical early maize cultivars in contrasting environments. Agronomy Journal 103 (3): 717-729
Bekele, A. and Nageshwar, R. T. (2013). Estimates of heritability, genetic advance and correlation study for yield and it’s attributes in maize (Zea mays L.). Journal of Plant Sciences 2(1):1-4
Bolanos, J. and Edmeades, G. O. (1996). The importance of the anthesis-silking interval in breeding for drought tolerance in tropical maize. Field Crop. 48:65-80
Edmeades, G. O., Bolaños, J., Hernandez, M. and Bello S., (1993). Causes for silk delay in a lowland tropical maize population. Crop Science 33: 1029-1035
FAO (2011). Food and Agricultural Organization of the United Nations (FAO), FAO Statistical Database, 2010, from http://faostat.fao.org
Hurley, M. B. and Rowart, J. S. (1999). Resistance to root growth and changes in the concentrations of ABA within the root and xylem sap during root-restriction stress. J. Exp. Bot. 50:799–804
IPCC (2007). Fourth Assessment Report: Synthesis, published online 17 November 2007. http://www.ipcc.ch/pdf/ assessment report/ar4/syr/ar4_syr.pdf
Ismail, A., Hall, A. and Bray, E. (1994). Drought and pot size effects on transpiration efficiency and carbon isotope discrimination of cowpea accessions and hybrids. Funct. Plant. Biol. 21:23–35
Ismail, M. R. and Davies, W. (1998). Root restriction affects leaf growth and stomatal response: the role of xylem sap ABA. Sci Hortic-Amsterdam. 74:257–268
Li, F., Mistele, B., Hu, Y., Chen, X. and Schmidhalter, U. (2014). Reflectance estimation of canopy nitrogen content in winter wheat using optimized hyperspectral spectral indices and partial least squares regression. Eur. J. Agron. 52:198-209.
Menkir, A. and Akintunde, A. O (2001). Evaluation of the performance of maize hybrids, improved open- pollinated and farmers’ local varieties under well-watered and drought stress conditions. Maydica, 46:227-238
Nayyar, H. and Gupta, D. (2006). Differential sensitivity of C3 and C4 plants to water deficit stress: association with oxidative stress and antioxidants. Environ. Exp. Bot. 58:106–113
Nguyen, H. T and Lee, B. W (2006). Assessment of rice leaf growth and nitrogen status by hyperspectral canopy reflectance and partial least square regression. Eur. J. Agron. 24:349-356.
Roberto, T. (2012). Phenotyping for drought tolerance of crops in the genomic era. Frontiers in physiology. 3:347. doi: 10.3389/fphys.2012.00347
SAS Institute Inc. (2015). SAS University Edition: Installation Guide for Windows. Cary, NC: SAS Institute Inc.
Shaibu, A. S., Rabiu, I. U., and Adnan A. A. (2015a). Variability of root and physiological traits of different groups of maize (Zea mays). Journal of Plant Breeding and Crop. 7(7): 233-239
Shaibu, A. S., Adnan, A. A. and Umar I. R. (2015b). Predicting grain yield of maize using drought tolerance traits. African Journal of Agricultural Research. 10(33): 3332-3337.
Shaibu, A. S., Adnan, A. A. and Rabiu I. U. (2015c). Genetic Correlation and Contribution of Some Physiological Traits to Yield in Some Selected Maize Genotypes. International Journal of Research in Science and Technology. 5(4): 1-11.
Vargas, M., Crossa, J., Sayre, K., Reynolds, M., Ramirez, M. E and Talbot, M. (1998). Interpreting genotype × environment interaction using partial least square regression. Crop Sci. 38:679-689
Wahid, A., Rasul, E., Rao, R. and Iqbal, R. (2005). Photosynthesis in leaf, stem, flower and fruit. In Mohammad P. (ed): Handbook of Photosynthesis Second Edition. Pp 479 – 500, CRC London.