Akmal, M., and Janssens, M.J.J. 2004. Productivity and light use efficiency of perennial ryegrass with contrasting water and nitrogen supplies. Field Crops Research 88: 143-155.
Andrade, F.H., Otegui, M.E., and Vega, C. 2000. Intercepted radiation at flowering and kernel number in maize. Agronomy Journal 92: 92-97.
Andriou, B., and Sinquet, H. 1993. Evaluation of structure description requirements for predicting gap fraction of vegetation canopies. Agricultural and Forest Meteorology 65: 207-227
Andriou, B., Ivanov, N., and Boissard, P. 1995. Simulation of light intercropping from a maize canopy model constructed by stereo plotting. Agricultural and Meteorology 75: 85-102.
Beheshti, A.R., and Behbodifard, B. 2010. Study dry matter accumulation and remobilization in grain sorghum Genotypes (Sorghum bicolor L. Moench) under drought stress. Australian Journal of Crop Science 4: 185-189.
Beheshti, A.R., Koocheki, A.R., and Nassiri Mahallati, M. 1999. Effect of planting pattern on light interception and radiation use efficiency in maize cultivars. Seed and Plant 4(18): 431-437. (In Persian with English Summary)
Birch, C.J., and Stewart, A.D. 1989. The effect of nitrogen fertilizer rate and timing on yield of hybrid forage sorghum from serial harvest. Australian Sorghum Workshop, Toowoomba, Australia.
Castro, F., and Fetcher, N. 1999. The effect of leaf clustering in the interception of light in vegetal canopies: theoretical considerations. Ecological Modelling 116: 125-134.
Ceotto, E., and Castelli, F. 2002. Radiation use efficiency in flue-cured tobacco (Nicotiana tabacum L.): Response to nitrogen supply, climatic variability and sink limitation. Field Crops Research 74: 117-130.
Dwyer, L.M., Stewart, D.W., Hamilton, R.I., and Honwing, L. 1992. Ear position and ver-tical distribution of leaf area in corn. Agronomy Journal 84: 430-438.
Eltelib, H.A. 2004. Effect of nitrogen application on growth yield and quality of four forage sorghum cultivars. MSc Thesis University of Khartoum Sudan, Sudan.
Flenet, F., Kiniry, J., Board, J., Westage, M., and Reicosky, D.C. 1996. Row spacing effects on light extinction coefficients of corn, sorghum, soybean, and sunflower. Agronomy Journal 88: 185-190.
Gardner, F.D., Walle, R., and Mecloud, D.E. 1990. Yield characteristic of ancient race of maize compared to a modern hybrid. Agronomy Journal 82: 864-868.
Green, D.S., Erickson, J.E., and Kruger, E.L. 2003. Foliar morphology and canopy nitrogen as predictors of light use efficiency in terrestrial vegetation. Agricultural and Forest Meteorology 115: 163-171.
Eltelib, H.A., and Eltom, E.A. 2006. Effect of time of nitrogen application on growth, yield and quality of four forage sorghum cultivars. Agricultural Journal 1(2): 59-63.
Javadi, H., Saberi, M.H., Azari Nasr Abad, A., and Khosravi, S. 2011. Investigation of effect of rates and methods of distribution of nitrogen fertilization on characteristics of quality and quantity of sorghum var, speed feed. Iranian Journal of Field Crops Research 8: 384-392. (In Persian with English summery)
Kemanian, A.R., Stockle, C.O., and Huggins, D.R. 2004.Variability of barley radiation use efficiency. Crop Science 44: 1662-1672.
Lecoeur, J., and Ney, B. 2003.Change with time in potential radiation use efficiency in field pea. European Journal of Agronomy 19: 91-105.
Madoni, G.A., and Otegui, M.E. 1996. Leaf area, light interception, and crops development in maize. Field Crops Research 48: 81-87.
Monteith, J.L.1979. Solar radiation and productivity in tropical ecosystems. Journal of Applied Ecology 9: 747-766.
Muchow, R.C., Sinclair, T.R., and Rennetl, I.M. 1990.Temperature and solar radiation effect on potential maize yield across location. Agronomy Journal 82: 238-243.
Novoa, R., and Loomis, R.S. 1981. Nitrogen and plant production. Plant and Soil 58: 177-204
Parsa, S., Koocheki, A., Nassiri Mahallati, M., and Ghaemi, A. 2007. Trend absorption and radiation use efficiency in sugar beet. Iranian Journal of Field Crops Research 8(3): 384-392. (In Persian with English summery)
Richter, G.M., Jaggard, K.W., and Mitchell, R.A.C. 2001. Modelling radiation interception and radiation use efficiency for sugar beet under variable climatic stress. Agricultural and Forest Meteorology 109: 13-25.
Rietveld, M.R. 1987. A new method for estimating the regression in the formula relating solar radiation to sunshine. Agricultural Meteorology 19: 243-252.
Rizzalli, R.H., Villalobos, F.J., and Orgaz, F. 2002. Radiation interception, radiation use efficiency and dry matter partitioning in garlic (Allium sativum L.). European Journal of Agronomy 18: 33-43.
Rooney, W.L., Blumenthal, J., Bean, B., and Mullet, J.E. 2007. Designing sorghum a dedicated bioenergy feedstock. Biofuels Products and Biorefining 1: 147-157.
Rosati, A., and Jong, T.M.D. 2003. Estimation photosynthetic radiation use efficiency using incident light and photosynthesis of individual leaves. Annals of Botany 91: 869-877.
Rosati, A., Metcalf, S.G., and Lampinen, B.D. 2004. A simple method to estimate photosynthetic radiation use efficiency of canopies. Annals of Botany 93: 567-574.
Rosenthal, W.D., Arkin, G.F., and Howell, T.A. 1985. Transmitted and absorbed photosynthetically active radiation in grain sorghum. Agronomy Journal 77: 841-845.
Rosenthal, W.D., and Gerik, T.J. 1991. Radiation use efficiency among cotton cultivars. Agronomy Journal 83: 655-658.
Sinclaur, T.R., and Horie, T. 1989. Leaf nitrogen photosynthesis and crop radiation use efficiency: A review. Crop Science 29: 90-98.
Sinclaur, T.R., Shiraiwa, T., and Hammer, G.L. 1992.Variation in crop radiation use efficiency with increased diffuse radiation. Crop Science 32: 1281-1284