**Abstract**

Soil salinity has emerged as a global threat to sustainability of farming systems by deteriorating the quality and productivity of crops particularly in the coastal regions of the world. Although, as a C4 plant, maize (*Zea mays* L.) has ability to tolerate a medium level of salinity; but initial growth stages of maize are sensitive to salinity stress. Therefore, it is crucial to expand our understanding pertaining to maize response to salt stress and tolerance mechanisms for devising approaches to enhance maize adaptability in saline environments. Moreover, maize crop undergoes several physiological changes and adapts some mechanism to overcome the salinity stress. Different mitigation strategies like application of chemicals, plant growth-promoting hormones, and use of genetic and molecular techniques are used to manage salinity and may ensure crop productivity under changing climate. This chapter aimed to assess the recent advancement pertaining to salinity stress influence on the physio-biochemical processes in maize and to draw the relationship between yield components and salinity stress. In addition, current study also highlights research gaps by focusing the seed enhancement techniques, phytohormones exogenous application and genetic improvement of maize under soil salinity.

**Keywords:** Salt stress, adverse effects, maize, productivity, seed enhancement

#### **1. Introduction**

Among various abiotic stresses, salt stress has posed one of the most severe threat to modern commercial oriented and profit-driven crop production at a global scale [1–4]. Besides soil salinity, utilization of saline water for irrigation purposes, particularly in the

#### **Figure 1.**

*Effect of salt stress on the initial growth of maize (adapted from Farooq et al. [12].*

low-lying coastal regions of many countries, has also been identified as a major yieldlimiting factor for boosting agriculture production [5, 6]. The detrimental impacts of salt stress manifest through a reduction in the relative water potential of plants which causes decline in plants growth [7], coupled to a negative effect in soil and water quality both in the short and long term [8, 9]. Salt stress is associated with the moisture stress that decreases plant growth and ultimately reduces plant yield even at soil moisture contents that are not limiting for crop productivity (**Figure 1**) [10, 11].

Similar to other C4 plants, maize is able to grow in both saline and non-saline conditions due to its stress adaptive potential and relatively tolerance against salinity [12–14]. Although salinity adversely affects maize growth and yield attributes throughout most of the plant cycle, the final impact on plant productivity depends upon the length and severity of the stress and the growth phase when the stress occurs [15, 16]. In general, and similar to the case for other row crops, the initial growth stage of maize is highly sensitive to salt stress. In a hydroponically grown study, Farooq et al. [12] observed the growth of roots and shoots of salt-treated (1.0 and 100 mM NaCl, applied one week after transplanting) maize variety cv. 'Pioneer 3906'. Authors reported a significant reduction in the plant height and dry matter biomass of plants treated with the highest salt concentration just 21 days after the beginning of the salt soaking study [12]. However, lower salt concentrations can severely impact normal crop growth and several studies have demonstrated that very low salt concentrations can reduce the growth cycle of maize plant due to oxidative stress before the occurrence of sodium toxicity in the plant [17–19]. The objectives of this chapter are to discuss a) the current and most recent knowledge regarding the influence of salinity stress on physio-biochemical processes and yield components in maize, and b) the seed enhancement technologies, phytohormones exogenous application and genetic improvement of maize against soil salinity stress.
