Differential Sensitivity of Pisum sativum L. Cultivars to Water-deficit Stress: Changes in Growth, Water Status, Chlorophyll Fluorescence and Gas Exchange Attributes

In recent years, drought has been a serious problem in Ethiopia and elsewhere which has adversely affected plant productivity.This study aimed to investigate the effects of water stress on growth, biomass and foliar characteristics in three cultivars (Brukitu, Tegegnech and Adi) of Pisum sativum.The control plant pots were uniformly irrigated at 3 day intervals to maintain 100% field capacity.Water-stress conditions were imposed by subjecting plants to a gradual decrease of soil water availability such as watering at 6 day intervals (slight-stress condition), 9 day intervals (mild-stress condition) and 12 day intervals (severe-stress condition).Results revealed significant differences among the cultivars, water-stress treatments and their interaction, indicating the cultivars variability and differential response to water stress.Water stress adversely affected growth, biomass production, leaf water status and other leaf characteristics such as pigment concentration (chlorophyll a, b and total chlorophyll), maximum quantum yield of photosystem II (PS II) (Fv/Fm), net photosynthetic rate, stomatal conductance and transpiration rate in all cultivars, as stress level was increased in comparison to control plants.The relatively less decline in the studied parameters of Tegegnech exhibited a reasonable tolerance ability of this cultivar, whereas Brukitu and Adi proved to be sensitive to water-deficit condition.