**Conflicts of interest**

*Landraces - Traditional Variety and Natural Breed*

activity soil salinity tolerance can be enhanced. It also determined that this approach can improve the plant tolerance towards salinity, ROS and Na<sup>+</sup>

**6.2 Combined effects of biochar and plant growth-promoting bacterial** 

Employing the salt tolerant PGPR to enhance crop productivity has been a sustainable and efficient method [119–122]. Researchers have documented that PGPR produced the exopolysaccharide (EPSs) that prevent the uptake of Na + ions by sequestering these ions [123, 124]. Studies demonstrated that few PGPR have an important enzyme, ACC- deaminase, which can reduce ethylene production by metabolizing ACC into ammonia. ACC is the precursor of ethylene and a-ketobutyrate [125–127]. Unlike PGPR, plant growth-promoting bacterial endophytes colonize the internal tissues of plants without causing any harm to the plants [128]. It can lead to several physiological modifications that contribute to plant growth and development [129–131]. These, plant growth-promoting bacterial endophytes may promote plant growth by adopting the similar mechanisms as observed in PGPR [132]. Thus, it is proved that plant growth-promoting bacterial endophytes are more effective in promoting plant growth even under severe stresses as compared to PGPR. Different researchers have demonstrated that for reducing soil salinity addition of biochar along with endophytic bacteria is an efficient and environment

For enhancing crop growth and yield, use of biochar is cost effective and eco-friendly option to boost water and nutrient-holding capacity of soil [134–137]. Application of biochar has positive effects on physicochemical properties of soil. Moreover, Biochar can also improve a variety of soil microbes by providing them a favorable habitat and nourishment [138]. Thus, it is an excellent solution for

There are three important mechanisms underlying biochar-mediated reduction

b.Regulation of ions concentration in soil solution by liberating mineral nutrients

c.Dilution of soil solution via increasing available moisture contents of soil to

Reclamation of saline soils is mainly achieved by employing various physicochemical processes. However, these processes are not sustainable and considered inefficient in the case of high salt concentration. PGPR contain a vital enzyme, 1-aminocyclopropane-1-carboxylate deaminase that can decrease salinity induced ethylene production. Silicon and elemental sulfur can also be applied to reduce the negative effects of soil salinity on plants. The organic matter such as press mud usually contains about 70% lime, 15–20% organic matter and 23% sugar. This organic

on biochar resulting in reduced availability of Na<sup>+</sup>

recycling organic waste and solution to environmental pollution.

saline environment to improve growth and yield of plants [118].

**endophytes on alleviating salt stress in maize**

friendly approach [133].

of salt stress in plants. These include:

reduce the osmotic stress [139].

a.High adsorption of Na<sup>+</sup>

soil solution

**7. Conclusion**

[118]. PGPR promote the growth of plants via synthesis of phytohormones, exopolysaccharides, volatile organic compounds and different other mechanisms [118]. Recently, it has been found that both Si and PGPR can enhance plants tolerance to

/K+ ratio

in

**124**

The authors declare no conflict of interest.
