Tolerance of Vegetables to Salinity and Alkalinity-A Review

Abstract

Salinity and alkalinity stress have major impact on vegetable crops in the form of their growth, development and yield. Tolerance and yield of a crop are complex genetic traits which are difficult to maintain simultaneously since salt tress may occur as a catastrophic agent, be imposed continuously or intermittently or become gradually more severe stress. Adverse effects of salinity may be due to ion cytotoxicity and osmotic stress which disrupt homeostasis in water potential and ionic distribution due to disordering in cohesions of membrane lipids and proteins, and influence various physiological and biochemical processes. To review the tolerance of vegetable crops to salinity and alkalinity, the present paper collates the existing experimental data sets establishing the salt tolerance limits of various vegetable crops under saline/alkali environment either in the soil root zone or that created due to application of saline/alkali water for crop production. The relative tolerance of different vegetable crops can easily be seen through the data presented in this paper. Since a good crop stand is necessary for higher yields, the crop sensitivity at germination/initial growth stage must be kept in view while selecting a crop and to ensure optimum root environment for the selected crop. Vegetable crops are generally more sensitive to salts than arable, fodder, pulse and oil seed crops. Spinach, celery and cabbage are highly tolerant, as 50% reduction in yield takes place at a high ECe of 10 dS m-1. Selection and breeding of salt-resistant crop varieties offer tremendous possibilities of utilizing saline water resources for crop production. Genetic enhancement using molecular technologies has revolutionized plant breeding.