Abdollahi, H. 2011. Pear, Butany, Cultivars and Rootstocks. Publication of Agricultural Education, Iranian Ministry of Agriculture, Tehran, Iran. 196pp. (in Persian). Abdollahi, H., Atashkar, D., and Alizadeh, A. 2012. Comparison of dwarfing effects in two hawthorn and quince rootstocks on some commercial pear cultivars. Iranian Journal of Horticaltural Sciences 43: 53-63 (in Persian). Alonso, J. M., Gomez-Aparisi, J., Anson, J. M., Espiau, M. T., and Carrera, M. 2011. Evaluation of the OHxF selections as an alternative to quince rootstocks for pear: Agronomical performance of ‘Conference’ and‘Doyenne du Comice’. Acta Horticulturae 903: 451-456. Anonymous 2011. Agricultural Statistics. Ministry of Jihad-e-Agriculture, Tehran, Iran (in Persian). Bakshi, P., and Singh, D. R. 2010. Rootstocks. pp.147-161. In: Sharma, R. M., Pandeyand, S. N., and Pandey, V. (eds.), The pear: Production, Post-Harvest Management and Protection. IBDC Publishers, Punjab, India. Davarynejad. G. H., Shahriari, F., and Hassanpour, H. 2008. Identification of graft incompatibility of pear cultivars on quince rootstock by using isozymes banding pattern and starch. Asian Journal of Plant Sciences 7: 109-112. Du Plooy, P., Jacobs, G., and Cook, N. C. 2002. Quantification of bearing habit on thebasis of lateral bud growth of seven pear cultivars grown under conditions ofinadequate winter chilling in South Africa. Scientia Horticulturae 95: 185-192. Elkins, R., Bell, R., and Einhorn, T. 2012. Needs assessment for future US pear rootstock research directions based on the current state of pear production and rootstock research. Journal of the American Pomological Society 66: 153-163. Francescatto, P., Pazzin, D., Gazolla Nero, A., Fachinello, J., and Giacobbo, C. 2014 .Evaluation of graft compatibility between quince rootstocks and pear scions. Acta Horticulturae 872: 253-259. Galli, F., Ancarani, S., Serra, S., and Musacchi, S. 2011. Training systems and rootstocksfor high density planting (HDP) of the cultivar ‘Abbé Fétel’: Developmental trials in Italy. Acta Horticulturae 909: 277-280. Galli, F., Ancarani, V., and Musacchi, S. 2010. La medio-alta densita del pero assicuraproduzioni e qualita. L’informatore Agrario 49: 46-48. Ghasemi, A., Nasiri, J., and Yahyabadi, M. 2010. Study of the relative tolerance of quince (Cydonia oblonga Mill.) rootstocks to different bicarbonate concentrations. Seed and Plant Production Journal 26-2: 137-151 (in Persian). Haak, E., Kviklys, D., and Lepsis, J. 2006. Comparison of Cydonia and Pyrus rootstocks in Stonia, Latvia and Lithuania. Sodininkyste Ir Darzininkyste 25: 322-326. Hartmann, H. T., Kester, D. E., Davies, F. T., and Geneve, R. L. 2002. Plant Propagation: Principles and Practices. Prentice Hall, New Jersey, USA. 880pp. Hassani, G. H., Doulati Baneh, H., and Mahmoud Zadeh, H. 2012. Fruit yield efficiency and some vegetative characteristics of commercial and spur type apple cultivars. Plant and Seed Production Journal 28-2: 373-376 (in Persian). Iglesias, I., and Asin, L. 2005. Performance of ‘Conference’ pear on self-rooted trees and several Old Home× Farmingdale, seedling and quince rootstocks in Spain. Acta Horticulturae 671: 485-491. Ikinci, A., Bolat, I., Ercisli, S., and Kodak, O. 2014. Influence of rootstocks on growth, yield, fruit quality and leaf mineral element contents of pear cv. Santa Maria in semi- arid conditions. Biological Research 47: 71-79. Jackson, J. E. 2003. Biology of Apples and Pears. Cambridge University Press, Cambridge, United Kingdom. 488pp. Lepsis, J., Lepse, L., Kviklys, D., and Univer, N. 2013. Evaluation of pear rootstocks for the cultivar ‘Suvenirs’ in the Baltic region. Natural, Exact and Applied Sciences 67: 145-150. Maas, F. 2008. Evaluation of Pyrus and quince rootstocks for high density pear orchards. Acta Horticulturae 800: 599-609. Machado, B. D., Rufato, L., Kretzschmar, A. A., Bogo, A., Silveira, F. N., and Magro, M. 2014. Effect of plant densities and cultivars on vegetative and productive variables of European pears in Southern Brazil. Acta Horticulturae 1058: 193-197. Musacchi, S., Ancarini, V., Grandi, M., and Sansavini, S. 2008. Comparative field performance of cvs. Sensation, Red Bartlett and Cascade grafted to six quince and pear clonal seedling rootstocks. Acta Horticulturae 596: 385-388. North, M., and Cook, N. 2008. Effect of six rootstocks on ‘Forelle’ pear tree growth, production, fruit quality and leaf mineral content. Acta Horticulturae 772: 97-103. Palmer, J. W. 2002. Effect of spacing and rootstock on the performance of ‘Comice’ pear in New Zealand. Acta Horticulturae 596: 609-614. Radnia, H. 1996. Fruit Tree Rootstocks. Publication of Agricultural Education, Karaj, Iran. 637pp. (in Persian). Rahmati, M., Arzani, K., and Yadollahi, H. 2015. Variation in some european pear (Pyrus communis L.) seedling rootstock populations using morphological characteristics. Seed and Plant Improvement Journal 31-1: 391-397 (in Persian). Robinson, T. L. 2010. High density pear production: an opportunity for NY Growers. New York Fruit Quarterly 18: 5-10. Rufato, L., Machado, B. D., Kretzschmar, A. A., Bogo, A., Luz, A. R., and Marcon Filho, J. L. 2014. Effect of high plant density on growth and production variables of european pear cultivars and quince rootstock combinations in southern Brazil. Acta Horticulturae 1058: 71-76. Webster, A. D. 1998. A brief review of pear rootstock development. Acta Horticulturae 475: 135-142. Webster, A. D. 2002. Factors influencing the flowering, fruit set and fruit growth of European pears. Acta Horticulturae 596: 699-709. Webster, A. D., Tobutt, K. R., James, D. J., Evans, K. M., and Alson, F. A. 1997. Rootstock breeding and orchard testing at horticulture research international-East Malling. Acta Horticulturae 451: 83-88. Wertheim, S. J. 2002. Rootstocks for European pear: A review. Acta Horticulturae 596: 299-309.