Assessment of salinity stress effect on six contrasting wheat genotypes during grain filling in simulated field growing conditions

A field experiment was conducted to evaluate the effect of the salinity stress on plants physical and grain yields attribute, also changes at proteomic level in grains of different stages were investigated. Six contrasting wheat genotypes, salt-tolerant (Kharchia-65, KRL-19, KRL-99, KRL-213), and salt-susceptible (HD-2329, PBW-373) were selected and exposed to four salinity levels (control, 100-, 200-, and 300-mM NaCl). Significant changes were observed in 1000 kernel weight, spike length, and the number of seeds per spike, while changes in plant height were negligible. The kernel weight of the wheat cultivar ‘Kharchia-65’ showed a minimum reduction (7%) when subjected to salt stress of 300 mM compared with the control, followed by ‘KRL-213’ (8%), ‘KRL-99’ (9%), ‘KRL-19’ (16%), and ‘PBW-373’ (32%), and HD-2329 showed maximum reduction (36%). The protein content was increased significantly in stressed plants than control plants, and in HD-2329, protein content was 10.07 ± 0.01% in control which increased to 13.46 ± 0.02% at 300-mM NaCl. It was observed that stress has more effect on susceptible lines than the tolerant lines. Seed protein fractionation was done, and the percent composition of albumin–globulin, gliadin, and glutenin was calculated during seed developmental stages. An increasing pattern of gliadin and the gli–glu ratio (1.01 in control to 2.99 in stressed condition in PBW-343) was observed in all the genotypes with increasing salt stress-induced conditions. The changes in polypeptide pattern were also analyzed for gliadin and glutenins using 1D SDS-PAGE under reducing conditions, and it was concluded that as stress conditions increases, it negatively affects the wheat cultivars.