Chickpea (Cicer arietinum L.) physiological, chemical and growth responses to irrigation with saline water

Chickpea (Cicer arietinum L.) is the third most important food legume grown in the world and a favourite food crop in Morocco. Morocco is a semi-arid country with limited fresh water resources. In order to meet the food demand, increasing attention is being given to the use of non-conventional water resources such as saline/brackish water and treated waste water for irrigation. With this in mind, an experiment was conducted in the south of Morocco to investigate the effect of irrigation with saline water on a local variety of chickpea. Irrigation with water of different salinity levels was carried out on pot experiments. Differences in water uptake and plant growth; as well as proline, soluble sugar, and Na+ and K+ contents of the plant were quantified. The results showed a negative relationship between increasing water salinity and most of the measured plant growth parameters. Irrigation water salinity has negatively affected growth and biomass accumulation and led to reduced grain yield, water uptake and water productivity. In contrast, proline, soluble sugars, Na+ and Na+: K+ ratio increased with increasing irrigation water salinity. The findings highlighted the role of proline and soluble sugars as osmolytes produced by chickpea to mitigate the effect of salinity stress. The added value of these results is that the crop’s responses to salinity are quantified. The obtained values can be used to determine ‘threshold values’; should the salinity of the irrigation water go above these threshold values one may expect the crop yield parameters to be affected. The quantified responses also indicate the rate of change of yield parameters in response to the irrigation water salinity level. This could help in avoiding significant yield reduction when deciding on the irrigation water salinity level to be used for the studied chickpea variety.