In search of the solution to Cr toxicity a two-year pot experiment (completely randomized design with three replications), in three genetically different varieties of sorghum (SSG 59-3, HJ 513 and HJ 541) under Cr toxicity (2 and 4 ppm) was conducted to determine the effect of glycine betaine (50 and 100mM) and Arbuscular mycorrhizal fungi (AMF) on the antioxidant system (enzymes viz. superoxide dismutase, ascorbate peroxidase, catalase, glutathione reductase, peroxidase and metabolites viz. glutathione, ascorbate, proline, β-carotene) along with Cr accumulation and indices of oxidative stress parameters (polyphenol oxidase, hydrogen peroxide and malondialdehyde) at two growth stages (vegetative and grain filling). According to results; Cr stress (2 & 4 ppm) increased its accumulation and indices of oxidative stresses significantly (p≤0.05) in all varieties of sorghum at both growth stages. However, soil application of glycine betaine (GB) and AMF decreased Cr accumulation and indices of oxidative stress by increasing antioxidant enzymes and metabolites activities at both growth stages in all varieties. The combination of 100mM GB with AMF was observed most significant (p≤0.05) in decreasing oxidative stress and improved the antioxidant system’s activities. The SSG 59-3 cultivar showed the lowest Cr accumulation indices of oxidative stress and highest antioxidant system’s activity among these three cultivars at both growth stages. Thus, SSG 59-3 was found most tolerant cultivars followed by HJ 513 and then HJ 541. These findings suggest that both GB and AMF, either individually or combined can play a positive role to reduce oxidative stress and increased antioxidant attributes under Cr toxicity in sorghum.

The present research was conducted in the screen house of the department of biochemistry, college of basic sciences & humanities, Chaudhary Charan Singh Haryana Agricultural University, Hisar, Haryana (India). Three varieties of sorghum (Sorghum bicolour L.) viz. HJ-541, HJ 513 and SSG 59-3 were procured from the forage section of the university. The toxic effects of hexavalent Cr, observed on sorghum plant growth along with possible reasons at two growth stages viz. vegetative (35 DAS) and grain filling (95 DAS) stages. The varieties of sorghum were tested for the amelioration of chromium toxicity (2 & 4 ppm) by exogenous application of GB (50 & 100 mM) and AMF in soil both individually and their combination, in completely randomized block design. The observations were recorded for chromium accumulation; antioxidant defence system enzymes viz. SOD, APX, CAT, GR, POD and metabolites viz. glutathione, proline, AsA, β-carotene; and indices of oxidative stress parameters viz. H₂O₂, MDA, PPO. The effects of GB and AMF on these different biochemical and antioxidant parameters during Cr stress were studied and analysed fresh leaf sample except for Cr accumulation which was performed in all three parts viz. roots stems and leaves.

The dataset represent the analysis of mean values of data collected randomly from three replications from two year experiments; respectively.