Asian Journal of Research in Crop Science

Assessment of Drought Tolerance Indices of Sorghum (Sorghum bicolor L.) under Different Water Regimes

Taiwo Temidayo Grace — 2026-06-27

Drought stress is one of the major environmental factors limiting sorghum productivity, particularly in semi-arid and drought-prone regions where water availability is often inadequate for optimum crop growth and yield. Sorghum (Sorghum bicolor (L.) Moench), an important cereal crop cultivated for food, feed and industrial purposes, exhibits varying levels of tolerance to moisture stress among genotypes.

This study was therefore conducted in two trials to evaluate the drought tolerance of six sorghum varieties using yield-based drought tolerance indices under differential watering regimes.

The experiment was conducted in a screenhouse at the Department of Crop, Soil and Pest Management, Federal University of Technology, Akure, Nigeria, using a 6 × 3 factorial arrangement laid out in a completely randomised design (CRD) with three replications. The treatments consisted of six sorghum varieties (CSR-01, Bida local, SK5912, SAMSORG 14, SAMSORG 17 and SAMSORG 44) and three watering regimes corresponding to 40%, 60% and 100% field capacity. Data collected included grain yield under stress (Ys) and non-stress (Yp) conditions, from which drought tolerance indices, including tolerance index (TOL), mean productivity (MP), geometric mean productivity (GMP), stress susceptibility index (SSI) and stress tolerance index (STI), were computed.

The results from both trials revealed significant variation among the sorghum varieties under different watering regimes. Grain yield generally increased with increasing water availability. In Trial 1, Bida local recorded the highest grain yield under stress and non-stress conditions, with Ys and Yp values of 5.62 and 10.02 g plant⁻¹, respectively, whereas CSR-01 recorded the lowest yield values. Similarly, in Trial 2, Bida local maintained the highest Ys value (2.87 g plant⁻¹), while its Yp value was 3.39 g plant⁻¹. Bida local consistently recorded the highest MP, GMP and STI values across both trials, indicating superior drought tolerance and yield stability. SK5912 also demonstrated relatively high drought tolerance and stable yield performance under moisture stress conditions. Correlation analysis revealed strong positive associations between grain yield under stress and MP (r = 0.96), GMP (r = 0.97) and STI (r = 0.94), while grain yield under non-stress conditions showed highly significant positive correlations with MP (r = 0.97), GMP (r = 0.95) and STI (r = 0.99). In contrast, stress susceptibility index (SSI) exhibited negative associations with grain yield and other drought tolerance indices.

The study concluded that MP, GMP and STI are reliable indices for identifying drought-tolerant sorghum genotypes. Bida local and SK5912 were identified as the most drought-tolerant and stable varieties across the two trials and are therefore recommended for cultivation in drought-prone environments and for use in sorghum breeding programmes aimed at improving drought tolerance and yield stability.

Protective Effects of Humic Acid on Growth and Photosynthetic Pigment Content of Tomato Plants (Solanum lycopersicum L.) under Salt Stress

Fatma Kaplan — 2026-07-02

Salinity is an important abiotic stress factor that restricts tomato growth and productivity, particularly in arid and semi-arid regions. This study evaluated the effects of foliar humic acid application on the growth and photosynthetic pigment responses of tomato plants exposed to salt stress. Tomato plants (Solanum lycopersicum L. cv. Falcon) were grown under greenhouse conditions in a randomised complete block design with four replications. Four treatments were applied: control, 100 mM NaCl, 200 ppm humic acid, and 100 mM NaCl combined with 200 ppm humic acid. Treatments were applied once weekly for eight weeks. Plant height, plant fresh and dry weight, root fresh and dry weight, root length, chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid contents were determined. Salt stress reduced plant fresh weight by 17.4%, plant dry weight by 11.7%, root length by 10.0%, and total chlorophyll content by 49.4% compared with the control. Humic acid application under salt stress improved several growth parameters compared with salt stress alone. In the combined salt and humic acid treatment, plant fresh weight increased by 13.2%, plant dry weight by 23.3%, root fresh weight by 29.4%, and root length by 14.0% compared with the salt-stressed group. Total chlorophyll content was also numerically higher under the combined treatment than under salt stress alone, although this difference was not statistically significant. Correlation analysis showed a strong positive relationship between chlorophyll a and chlorophyll b. Multivariate analyses indicated that salt-stressed plants differed from control and humic-acid-treated plants, while humic acid partially moderated the salt-stress response. These findings suggest that 200 ppm foliar humic acid may help reduce some adverse effects of salt stress in tomato plants under greenhouse conditions.

Comparative Effects of Organic and Inorganic Fertilizers on Growth and Yield of Maize (Zea mays L.) in Ogbomosho, Oyo State, Nigeria

Adebowale Eniola Yusuf — 2026-07-10

Aim: This study evaluated the comparative effects of organic fertilizer (poultry manure) and inorganic fertilizer (NPK 15-15-15) on the growth and yield of maize (Zea mays L.) in Ogbomosho, Oyo State, Nigeria.

Methodology: The experiment was conducted using a Randomised Complete Block Design (RCBD) with three treatments: poultry manure, NPK 15-15-15 fertilizer, and a control with no fertilizer application, each replicated five times. The growth parameters measured included plant height and number of leaves, while yield per plant was assessed at harvest. The data collected were subjected to analysis of variance (ANOVA) at the 5% probability level.

Results: Fertilizer application significantly (P < 0.05) improved maize growth and yield compared with the control. Inorganic fertilizer recorded the highest mean plant height (93.0 cm), number of leaves (17.0), and yield per plant (1.91 kg), followed by organic fertilizer (86.2 cm, 15.2 leaves, and 1.36 kg), while the control recorded the lowest values. The ANOVA results indicated significant differences among treatments for all measured parameters.

Conclusion: Both organic and inorganic fertilizers significantly improved maize growth and yield under the conditions of this study. Although NPK 15-15-15 produced higher growth and yield values, poultry manure remains an important nutrient source for improving soil quality and supporting sustainable crop production. An integrated nutrient management approach that combines organic and inorganic fertilizers is recommended to enhance maize productivity while maintaining long-term soil fertility in the study area.

Beyond Soil: Plant Intelligence, Bio-Digital Farming Systems, and the Architecture of a Post-Soil Civilisation

Moaed Ali Al Meselmani — 2026-06-15

Hydroponic cultivation uses up to 90 percent less water than conventional soil-based agriculture, can produce substantially higher yields per unit of land area, and can operate in environments entirely unsuitable for traditional farming, from arid desert facilities to orbital space stations. This paper presents a conceptual and technical framework for the next generation of soilless agriculture: the Bio-Digital Hydroponic Ecosystem (BDHE), a four-layer architecture in which farms continuously monitor, interpret, and respond to the biological signals of their plants. Eight paradigm shifts follow from this framework. Continuous bioelectric sensing will guide robotic repositioning of crops toward their optimal light environment (Kinetic Phytometric Farming). Multimodal electrical signal monitoring will detect disease and nutritional stress days before any visible symptom appears (Bioelectric Crop Interfaces). Chemical messages that roots release into the nutrient solution will be read and answered in real time (Hydrolingual Nutrient Networks). Electrical, acoustic, optical, and volatile chemical signals will combine into a continuous well-being index for every individual plant (Phyto-Sentiment Analysis). Engineered microbial consortia will adjust nutrient chemistry dynamically in response to real-time plant demand (Adaptive Living Solutions). All cultivation operations will synchronise with the plant's circadian biology for measurably superior outcomes (Phyto-Chronobiological Farming). A predictive computational model will be updated continuously from sensor data for every plant (Digital Plant Twins). And knowledge gained at the individual plant and module level will propagate across facilities and globally (Distributed Phyto-Intelligence Networks). Each paradigm is grounded in published science, with limitations acknowledged throughout. The paper addresses economic feasibility, energy demands, regulatory pathways, equity of access, and workforce requirements. A phased commercialisation roadmap spans 2028 to 2065. The paper concludes that advanced hydroponics is not merely an agricultural technology but the foundation of a food system capable of sustaining human civilisation without dependence on soil or predictable rainfall.

Vermicomposting as a Sustainable Detoxification Strategy for Pesticide-Contaminated Agricultural Wastes: Mechanisms and Earthworm Physiological Responses

Chittimothu Suresh Babu — 2026-06-20

Pesticide-contaminated agricultural residues represent an important waste-management concern because residues may persist in crop biomass after harvest and enter soil, water, or atmospheric pathways through unsuitable disposal practices. This review examines vermicomposting as a biological approach for reducing pesticide loads in agricultural wastes and discusses the mechanisms by which earthworms and associated microorganisms may contribute to detoxification. The manuscript synthesises literature on pesticide-contaminated crop residues, pesticide fate during vermicomposting, earthworm physiological responses, process-control factors, and safety evaluation of vermicompost outputs. Particular attention is given to enzymatic hydrolysis, oxidative transformation, microbial co-metabolism, sorption, humification, and bound-residue formation within the vermicomposting matrix. Earthworm responses, including acetylcholinesterase inhibition, oxidative stress, coelomocyte activity, heat-shock protein expression, reproduction, and survival, are considered potential indicators of pesticide stress and process performance. The review also discusses operational variables, including feedstock pre-treatment, carbon-to-nitrogen ratio, moisture, temperature, aeration, and worm species selection. Available evidence suggests that vermicomposting can contribute to the reduction of several pesticide classes in organic residues under controlled conditions, although degradation efficiency varies with pesticide chemistry, initial concentration, substrate composition, earthworm species, and processing duration. The review further highlights the need for standardised analytical methods, mixture-toxicity studies, field-scale validation, and clearer regulatory benchmarks for vermicompost derived from contaminated feedstocks. Overall, vermicomposting appears to be a promising component of sustainable agricultural waste management, but its application to pesticide-contaminated residues requires careful feedstock characterisation, process monitoring, and ecotoxicological verification before routine agronomic use.