Norah Johal

Wheat ( Triticum aestivum L.), a major global staple, suffers yield and quality losses due to high temperature stress. This study evaluated 60 spring × winter derivative lines, including five checks, for yield stability under early, timely, and late sowing during 2019‐2020 and 2020‐2021 at Punjab Agricultural University, Ludhiana, India. Thirteen yield‑based stress indices (stress tolerance [TOL], stress tolerance index, stress susceptibility percentage index, yield index, yield stability index [YSI], relative stress index, mean productivity, geometric mean productivity, harmonic mean, mean yield (relative) performance [MYP], percent yield reduction [PYR], reduction rate of 1000 kernel weight, and heat susceptibility index) were calculated from grain yield across environments. Hierarchical clustering (Ward's method, Euclidean distance) produced three clusters, with final merging distances of 15.19 for timely versus early (TE) and 13.78 for timely versus late (TL), indicating clear divergence among environments. Under timely sowing, lines showed better tolerance (mean TOL: −166.32) and stability (mean YSI: 1.19), with some yield gains (mean PYR: −19.10%). Late sowing caused higher susceptibility (mean TOL: 265.39) and marked yield loss (mean PYR: 29.33%). Although temperature differed among sowing dates, maximum temperature during grain filling stayed below terminal heat thresholds, so responses reflect sowing‑time‑associated temperature variations rather than true heat stress. Across indices and multivariate analyses, lines EWS 78, EWS 252, EWS 431, EWS 421, EWS 439, and EWS 282 combined higher mean yield with favorable tolerance in both TE and TL, whereas EWS 1, EWS 139, EWS 93, EWS 92, and EWS 94 were consistently temperature‑sensitive. Principal coordinate analysis confirmed strong shifts between TE and TL but highlighted a small subset of stable derivatives as promising donors for breeding wheat adapted to variable sowing windows and associated thermal regimes.

The over‐exploitation of groundwater in agriculture necessitates the adoption of water‐efficient practices. A field study (2020–2022) under cotton–wheat cropping in semi‐arid Punjab, India, evaluated subsurface drip irrigation (SSDI) with lateral depths (20, 25 and 30 cm), emitter spacings (20, 30 and 40 cm) and irrigation levels (60%, 80% and 100% ETc). Bayesian optimization was used for multicriteria decision‐making. The results revealed wheat sensitivity to lateral depth, with a significant yield reduction at 30 cm compared to 20 cm, whereas the deep root system of cotton mitigated such effects. Overall, SSDI at 80% ETc maintained system productivity (SP; 4343 kg ha ⁻¹ ) and net returns (NR; 2001.1 $ ha ⁻¹ ) comparable to full irrigation, in addition to 20% higher irrigation water productivity (WP). Additionally, it also resulted in 5%, 11%, 5% and 23% greater SP, NR, irrigation and net economic WP, respectively, than the recommended surface drip practice. Furthermore, multiresponse optimization identified 25.5‐cm lateral depth, 31.2‐cm emitter spacing and irrigation at 81% ETc as the optimum combination for SSDI. This configuration optimized productivity, water saving and profitability within permissible drainage losses (RMSE 0.4223). These findings not only underscore the resource conservation potential of SSDI but also demonstrate its capacity to maximize economic and environmental benefits.

The current study was carried out to study the changes in activities of carbohydrate metabolizing enzymes under drought stressed wheat (Triticum aestivum L.) (HD2967, PBW660 and WH1105) genotypes and how their regulation was maintained by exogenously applied cytokinins (kinetin and benzyl adenine) and trehalose: an osmoprotectant. Alterations in contents of various sugars (total soluble sugars, reducing sugars and non-reducing sugars) were recorded under control and drought stressed crop plants on foliar application of cytokinins and trehalose at vegetative and flag leaf stages. Drought stress significantly increased total soluble sugars (1.2, 1.4 folds), reducing sugars (1.1, 1.3 folds), non-reducing sugars (1.2, 1.5 folds) and sucrose content (1.3, 1.2 folds) at both vegetative stage and flag leaf stage respectively. Carbohydrate metabolizing enzymes viz., sucrose phosphate synthase (1.2 folds), acid invertase (1.1 folds) and sucrose synthase (1.4 folds) were significantly upregulated under drought stressed plants at flag leaf stage. However, the osmoprotectant mitigated the effect by lowering the enzymatic activities in treatments (T3-T6), T4 treatment (Drought + Kn(40g)+ Tre (1.5mM) had the most promising mitigating effect against drought stress at both the stages. A significant negative correlation was observed between grain yield and sugar metabolizing enzymes, specifically SPS (r = -0.70), SS (r = -0.67), and sucrose content (r = -0.70), during the vegetative stage. Moreover the acuteness of the grain yield with the starch content in loading plot indicates the regulation of sugar metabolism that underwent modifications in presence of exogenous PGRs (trehalose, kinetin and benzyl adenine) that leads to significant increase in starch content that ultimately enhances grain yield of wheat.

The current study was conducted to investigate the effects of EMF-r on germination parameters, stress indices and the antioxidative defense system in seedlings of the chickpea variety PBG 7 upon 0 (control), 1-hour, 2-hours, and 4-hours exposure durations to EMF-r with a frequency of 2850 MHz. Chickpea seeds (0–7 days) were exposed daily to the EMF-r and 4-h exposure showed the most prominent effect. The effect was more pronounced in terms of germination parameters, stress indices and antioxidative status. In terms of germination parameters, vigour index of seedlings was the most affected with respect to control counterparts. An increase in the MDA content indicates the membrane damage, which intensified along with increasing duration of EMF-r exposure. Antioxidative status in terms of SOD and POD was upregulated, especially after 4-h exposure to EMF-r. Also, photosynthetic pigments, i.e. chlorophyll a, total chlorophyll content reduced at this duration of exposure. Our findings suggest that 2850 MHz EMF-r affected the germination and growth of chickpea seedlings, and also altered the oxidative metabolism of irradiated samples, especially at 4-h exposure. Our results contribute to research focused on the effect of EMF-r on the entire life cycle and to identify the threshold window limit of EMF-r radiations and to what factors contribute for the plant to be attenuators.