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\hypersetup{pdftitle={Modelling of Leaf Area Senescence in Field"=grown Wheat},pdfauthor={Esmail Bakhshandeh, Afshin Soltani, Rahman Gadiryan},pdfsubject={Tropentag 2010: Abstract},pdfkeywords={LAI senescence, leaf area index, Model, Wheat},pdfpagemode=None,colorlinks=true}
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\parbox[b]{13.4cm}{\centering \large{\textbf{Tropentag, September 14-16, 2010, Zurich}}\\[1ex] \Large{``World Food System  ---\\A Contribution from Europe''\\[2ex]}}
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\Large{\textbf{Modelling of Leaf Area Senescence in Field"=grown Wheat\footnote{\textbf{Contact Address:} Esmail Bakhshandeh, Gorgan University of Agricultural Science and Natural Resources, Gorgan, Iran, Department of Agronomy, Iran Gorgan Department of Agronomy of Gorgan University of Agricultural Science and Natural Resources Gorgan Iran, 48131-81344~Gorgan, Iran, \mbox{e-mail}: \email{bakhshandehesmail@yahoo.com}}\\[0.8ex]}}
\normalsize{\textsc{Esmail Bakhshandeh$^{1}$, Afshin Soltani$^{2}$, Rahman Gadiryan$^{3}$}}
\end{center}
\begin{itemize*}
\item[]{\small{\textit{$^{1}$Gorgan University of Agricultural Science and Natural Resources, Gorgan, Iran, Department of Agronomy, Iran}}}
\item[]{\small{\textit{$^{2}$Gorgan University of Agricultural Sciences and Natural Resources, Department of Agronomy, Iran}}}
\item[]{\small{\textit{$^{3}$Gorgan University of Agricultural Science and Natural Resources, Gorgan, Iran, Department of Agronomy, }}}
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\index[author]{Bakhshandeh, Esmail}
\index[author]{Soltani, Afshin}
\index[author]{Gadiryan, Rahman}
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\textbf{Abstract}
\begin{abstract}
\normalsize{
The ability to predict leaf area development is crucial for crop simulation models. Leaf area development involves the appearance of new leaves, expansion of newly emerged leaves and the senescence of old leaves. LAI is most important factor on physiological and ecological studies. It is required to estimate interception of solar radiation and biomass production and it is also an important determination factor to partitioning evapotranspiration between evaporation and transpiration. Therefore, in order to quantify LAI senescence in wheat an experimental design of composite of analysis under randomised complete block design with four replications was conducted in 2008--2009 at Research Field of Gorgan University of Agricultural Science and Natural Resources, Gorgan, Iran. Treatments were included seven wheat cultivars (Arya, Darya, Kohdasht, Shirudi, Tajan, Taro and Zagros) and two conditions (Rainfed and Irrigated). Sampling was carried out to end growth season. An exponential equation [Y=a exp"=bx] was used to describe LAI senescence. Fitting of equation was performed two times \textbf{(1)}~for each treatment, separately and \textbf{(2)}~for pooled data. The results showed that there were not significantly difference between cultivars and conditions in equation coefficients [LAI at beginning phase of senescence \textbf{(a)}~and LAI senescence relative rate (b)]. Therefore, in this study an equation for all cultivars and conditions obtained based on mean coefficients that could describe as well as relationships between LAI senescence and growth degree day (GDD). As LAI senescence in wheat was best estimated by the equation [LAI=155.8 exp-0.0025×GDD, R$^{2}$ =0.81]. These parameters can satisfactory used in simulation of LAI senescence in wheat.}

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\noindent \textbf{Keywords:} LAI senescence, leaf area index, Model, Wheat
\index[key]{LAI senescence}
\index[key]{Leaf!area index}
\index[key]{Model}
\index[key]{Wheat}
\end{document}