عنوان مقاله [English]
For assessment of yield changes of wheat (cv. Sardari) and 14 modified genetically cultivars, a simulation experiment was conducted to select optimal plant characteristics based on maximum leaf area index, biomass of seed at filling time, biological yield, seed yield and harvest index, using SSM-Model in rain-fed conditions of urmia for 3 years (2011-2013). Results of simulations showed that the major effective parameter in increasing of grain yield was 20% decreasing in time till grain filling beginning (vegetative phase), 20% increasing in time till grain growth ending and 30 % inversing in radiation use efficiency. The maximum leaf area index, the highest biomass at grain filling time, biological yield, grain yield and harvest index were determined in modified cultivars like: C2, C12, and C8 respectively which was made by increasing in vegetative phase, upgrading of flowering phase (grain filling phase) and improvement of radiation use efficiency (RUE). In cluster analysis which was used by three methods (mean linkage, single linkage and centroid), three groups were obtained: C12 and C8 in group 1, C11 in group 2 and other cultivars in group 3(C1, C2, C3, C4, C5, C6, C7, C9, C10, C13, C14 and Sardari). Recognition analysis of functions indicated that the main effects on clustering of genotypes are LAImax and biomass at the beginning of seed growth. Results, as a whole, showed that it is necessary to take into account climatically changes, methods of increasing of grain filling period, earlier enterance to grain filling period and improvement of RUE in addition to achieving optimum LAI during vegetation growth period in wheat, because it could be the important impacts in increasing of grain yield of wheat.
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