Effect of water stress and plant density on canopy temperature, yield components and protein concentration of red bean (Phaseolus vulgaris L. cv. Akhtar)

In order to study the effects of different irrigation regimes and plant density on yieldcomponent and protein concentration and crop water stress index (CWSI), under research fieldconditions a split plot arrangement was conducted in completely randomized block designduring two years. The first factor of variables was the effects of 4 irrigation levels 120% (I1),100% (I2), 80% (I3) and 60% (I4) of Standard evapotranspiration and the second factor was thespacing of 5 cm (D1), 10 cm (D2) and 15 cm (D3) between plants within a row. Results indicatethat the number of pods in each plant and the grains in each pod decreased when densityincreased, but the hundred-grains-weight and the height of bean plants increased. Whenirrigation increased, various increases were observed in the yield, the number of pods in eachplant, the grains in each pod, the hundred-grains-weight and the height of bean plants, but thegrain protein decreased. Protein concentration increased with more severe water deficit in thesoil. The protein concentration directly correlated with total irrigation water during the growingseason (TI) and the exponential equation P=33* e -4E-04TI can be used for protein concentrationprediction. The effect of the irrigation water was significant and CWSI increased with increasedsoil water deficit. The effect of the density for CWSI was not significant. Grain yield (GY)directly correlated with CWSI and the exponential equation, GY=696.2(CWSI)-0.51 can be usedfor the prediction of grain yield. The CWSI value is useful for evaluating crop water stress inbeans and thus it could be useful in timing the irrigation. Results of this research indicate thatyield components such as height of bean plant, the number of pods in each plant and the numberof grains in each pod were significantly different by applying the different irrigation strategies atthe three different lengths of plant spacing within a row.