Effects of biofertilizers and nano iron-silicon oxide on yield, dry matter remobilization, and trend of changes of the grain filling of triticale under salinity stress

Salinity is the major abiotic stress factor negatively affecting numerous crop plants’ morphological and biochemical traits, resulting in reduced agricultural production and sustainability. Iron-silicon (Fe-Si) nanoparticles (NPs) and plant growth-promoting rhizobacteria can decrease abiotic stress and improve crop yield. Accordingly, a factorial experiment was conducted in 2021 under greenhouse conditions using a randomized complete block design with three replicates. The treatment included salinity at three levels (no salinity, 35 mM and 70 mM with sodium chloride), four levels of NP foliar application (foliar application with water as control, nano Si, nano Fe, and Fe-Si NPs), and four levels of plant growth-promoting rhizobacteria (PGPR; no application, Pseudomonas, Azospirillum, and Azospirillum and Pseudomonas applications). According to the results, the highest dry matter remobilization from shoot and stem and the contribution of stem reserves to the grain yield were found in severe salinity stress conditions. In addition, under 70 mM salinity stress conditions, PGPR and nano Fe-SiO applications increased carotenoid content (51.1%), leaf area index (39.4%), total Chl (31.4%), chlorophyll a (29.1%), grain-filling duration (22.2%), effective grain-filling duration (EGFD, 16.3%), and grain yield (12.8%) when compared to control (no PGPR and NP applications) at the same level of salinity. According to the findings, the application of PGPR and NPs increased the grain yield of triticale in salinity stress conditions because of improving the components of grain filling and some physiological features.