52 Felekariet al. Int. J. Biosci. 2014 RESEARCH PAPER OPEN ACCESS The effect of post anthesis source and sink limitation in wheat cultivars under moderate condition Hamzeh Felekari * , Mohammad Eghbal Ghobadi, Mokhtar Ghobadi, Saeid Jalali Honarmand, Mohsen Saeidi Department of Agronomy and Plant Breeding, Campus of Agriculture and Natural Resources, Razi University, Kermanshah, Iran Key words: Grain yield, wheat, source and sink reduction. http://dx.doi.org/10.12692/ijb/5.5.52-59 Article published on September 05, 2014 Abstract Source and sink reduction can effect on wheat (Triticumaestivum L.)yield. In order to determine the effect of source and sink limitation on yield and some agronomic characteristics in 4 bread wheat cultivars were performed an experimental at farm of Campus of Agriculture and Natural Resources, Razi University in Kermanshah in 2008-2009. Treatments included wheat cultivars as the main plot at 4 levels (‘Parsi’, ‘DN-11’, ‘Roshan’ and ‘Kohdasht’) and source and sink limitation as the sub plot at 5 levels (control (no defoliation), source limitation treatments includes defoliation flag leaf, defoliation other leaves, defoliation all leaves, and removing spikelet on one side of each spike using the forceps (sink limitation). Experiment was a randomized complete block design with three replications. Cultivar and source and sink limitation treatment had significant effect on dry mass, grain yield, grains spike -1 , 1000 grain weight, HI, Seed Length, Seed width, L/W and FFD. Highest grain yield was control (no limitation), Reduction percentage in spikelet removing, defoliated all leaves, defoliated flag leaf, and defoliated other leaves were 36%, 20%, 18% and 9%, respectively. Roshan cultivar had highest grain yield. Spikelet removing caused 41 percent reduction then control. Spikelet removing increased thousand grain weight (60.49 g), grain length (6.82 mm) and grain width (3.39 mm). L/W in defoliation of flag leaf (2.17) and defoliation of all leaves (2.13) were maximum. * Corresponding Author: HamzehFelegari  hamze1365@gmail.com International Journal of Biosciences | IJB | ISSN: 2220-6655 (Print) 2222-5234 (Online) http://www.innspub.net Vol. 5, No. 5, p. 52-59, 2014