Effects of drought stress and nitrogen on grain yield and some agronomic traits of red kidney bean cultivars

To study the effects of different irrigation levels and nitrogen on yield and yield components of red kidney beans, a factorial split plot experiment in a randomized complete block design with four replications was conducted at College of Agriculture and Natural Resources, University of Tehran (Karaj) in 2015. Three irrigation levels comprised of 60 (normal), 90 (mild water stress) and 120 mm (sever) cumulative evaporation from open pan class A assigned as main plots, four fertilizer treatments of zero (control), 50, 100 and 150 kg N ha-1 and bean cultivars (Akhtar & D81083) compound as sub plots.The results showed that water stress significantly reduces the number of pods per plant, seeds per pod, seed weight, seed yield, biological yield, harvest index, number of branches and plant height. Applied nitrogen significantly intensified all traits, except pod weight, plant height and harvest index. Two kidney beans significantly differed in all traits; however the line D81083 in terms of grain yield and other components performed better than Akhtar. D81083 line at normal irrigation with 150 kg N and the Akhtar line at water stress condition with no N fertilizer application, respectively had the highest and the lowest harvest index and seed weight. The interaction of water stress and nitrogen fertilizer on grain yield showed that the treatments of 150 kg N in normal irrigation had the highest and the control (not fertilizer) under severe water stress had the lowest yield however, the difference between 100 and 150 kg N ha- was not significant.