effect of drought stress on photo assimilate allocation of pinto bean (phaseolus vulgaris l.)

in order to estimate effects of drought stress on dry matter allocation of pinto bean (phaseolus vulgaris l.), an experiment was carried out as split plot based on complete randomized block design with four replications at zanjan university research farm. in this experiment,  two irrigation levels (optimum irrigation during growth season and post flowering drought stress) were set at main plots and  six pinto bean cultivars (khomein, cos16, sadri, ks21193, ks21191, ks21189) were set at sub plots. results showed that drought stress had significant effects on stem weight ratio and pod weight ratio. also, ks21191 genotype had the highest grain yield under drought stress because of less allocation of photoassimilates to leaves and higher pod weight and higher biomass. generally, cultivars that allocate less photoassimilates to leaves and stems and higher photoassimilates to pods had the priority under drought stress.