Journal of Tropical Crop Science Welcome to the online submission and editorial system of the Journal of Tropical Crop Science. The Journal of Tropical Crop Science (JTCS; p-ISSN: 2356-0169; e-ISSN: 2356-0177) is an open-access, international, peer-reviewed journal that publishes articles reporting research findings on in vivo and in vitro crop production and management under tropical conditions. Our open access policy allows immediate, free access to the articles and permits any user to read, download, copy, distribute, print, search, or link to the full texts of articles; crawl them for indexing; pass them as data to software; or use them for any other lawful purpose. The scope of the journal includes studies on crop production, breeding, seed technology, physiology, postharvest management, pests, and pathology of tropical cereals, vegetables, fruits, ornamentals, medicinal and plantation crops, soil, landscape, turf, and agroecological management. All articles are published under the Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0) license. Under the terms of this license, authors retain copyright and grant the journal the right of first publication. Others are free to copy, redistribute, and remix the material in any medium or format. Users must give appropriate attribution/credit, link to the original, include the name, provide license info, and keep their derivative work under CC BY-SA. JTCS is published by the Department of Agronomy and Horticulture, IPB University, Indonesia. We accept submissions from researchers worldwide. Our Editorial Board members are prominent and active international researchers in agriculture, horticulture, and biosciences. All accepted articles will be published upon payment of an article-processing charge of IDR 2,500,000 and will be freely available to all readers worldwide. JTCS has been indexed/registered in SCOPUS as of 20 March 2024 (SJR rating in progress), ASCI (Asian Science Citation Index), AGRIS FAO, and WORLD CATALOGUE LIBRARY. Journal of Tropical Crop Science accepts the following types of papers Original research papers: report the results of original research. The material should not have been previously published elsewhere. Review articles: cover a part of the subject with an active current interest. They may be submitted or invited. Original research papers and review articles should have a maximum of 8,000 words, including figures and tables. Short Communications: report of preliminary research results, newly developed methodology or modification of existing methodology, and results of the application of an earlier published research methodology on other crops or under different conditions. Short communications should be as completely documented, both by reference to the literature and description of the experimental procedures employed, as a regular research paper with a maximum of 2000 words, with a maximum of three tables or figures, and up to 20 references. PRINTED ISSN: 2356-0169 ELECTRONIC ISSN: 2356-0177 The Department of Agronomy and Horticulture, Faculty of Agriculture, IPB University JOURNALS: Jurnal Agronomi Indonesia Jurnal Hortikultura Indonesia Journal of Tropical Crop Science The Journal of Tropical Crop Science content is currently preserved in LOCKSS.
Department of Agronomy and Horticulture, IPB University
All publications by Journal of Tropical Crop Science is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Assessment of Major Diseases and Insect Pests of Horticultural Crops in Eastern Amhara, Ethiopia
Diseases and insect pests are serious problems affecting horticultural crops grown in mid and lowland areas. A systematic survey was conducted to assess the distribution, incidence, and severity/damage levels of diseases and insect pests of horticultural crops in the mid- and lowland areas of the North and South Wollo zones (Kalu, Tehuledere, Habru, and Kobo districts) during the 2017/2018 main and irrigation seasons. During the survey, a total of 279 fields on 14 different horticultural crop types were addressed. As revealed by the assessment, horticultural crops are subjected to numerous pests. Citrus woolly whitefly (Aleurothrixus floccosus) and leaf miner (Phyllocnistis citrella) on citrus; fruit flies (Thepritidea species) on coffee; diamondback moth (Plutella xylostella) on cabbage; and thrips on onion were the most destructive insect pests in the area. Especially, woolly whitefly in Kobo and leaf miner in Kalu districts were the major pests of citrus, with severities of 38.97% and 31.84%, respectively. Regardless of location, leaf miner was the most severe pest (42.31%) at the seedling stage of citrus. whereas, anthracnose (Colletotrichum species) and powdery mildew (Oidium caricae) on mango, anthracnose on avocado, purple blotch (Alternaria porri) on onion, and black sigatoka (Pseudocercospora fijiensis) on banana were found to be the major diseases in their order of damage level and occurrence. This clearly indicates the need for regular and targeted pest monitoring on the one hand and the development of management options for the most important horticultural crop pests of the area on the other.
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Optimizing Rice Seed (Oryza sativa L.) Production and Quality through Organic Fertilizer Application
Rice (Oryza sativa L.) is a vital cereal crop and primary food source for over half of the global population, especially in Asia, Africa, and Latin America. This study evaluated the effect of organic fertilizers on optimizing rice seed production and quality. Organic fertilizers improve soil physical, chemical, and biological properties, thereby enhancing nutrient availability. A study was conducted standard and premium organic fertilizers (petroganik), in a completely randomized design with six treatments: no fertilizer (control), (12.5% organic C) at 500 kg/ha, and the premium organic fertilizer (15% organic C) at 250, 500, 750, and 1000 kg/ha. With four replications, 24 experimental plots were established. Results showed that while application of premium organic fertilizer did not affect vegetative growth, it significantly increased the number of productive tillers and overall yield. Applying 500 kg/ha of premium organic fertilizer increased rice yield by up to 13% compared to the control, with a relative agronomic effectiveness of >95%. Seed quality improved, indicated by higher germination rates, vigor index, and maximum growth potential. The after-ripening period was shortened by two weeks compared to control seeds, i.e., from 5 to 3 weeks, but did not affect seed storability.
Genetic Variability, Correlation, and Path Analysis in F2 Population of Sorghum
Indonesian sorghum (Sorghum bicolor L.) germplasm with the highest genetic diversity can serve as a valuable resource for developing high-yielding cultivars. Therefore, the present research aimed to obtain information on genetic variability in the population and also determine the key traits associated with grain yield using correlation and path analysis in sorghum F2 population. The sorghum parental genotypes 'Demak 4' and 'Soraya 3', and a local high yielding IPB line, NS 19, NS 109, and NS 111, were used in the crosses. The F2 population was evaluated against parental cultivars and four check genotypes. The results showed that 64 individual plants were observed as transgressive segregants. Meanwhile, the number of leaves and plant height were controlled polygenically through additive genes. The traits of panicle diameter, dry panicle weight, and grain weight per panicle possessed the highest genotypic coefficient of variance. The traits dry panicle weight and diameter were significantly positively correlated with grain yield. The considerable positive correlation with dried panicle weight, panicle length, and diameter could be used as selection criteria. The path analysis reported that the observed agronomic traits explained 97.07% of the total variation in grain weight per panicle.
Effects of Ethephon and Fertilization on Latex Physiology and Rubber Yield in GT1, BPM 24, PB260 and IRR112 Clones
This study was conducted to evaluate the effects of ethephon stimulation and fertilization on latex production and physiological latex in different clones. This study was conducted in the experimental field of the Indonesian Rubber Research Institute in South Sumatra. The experiment was laid out in a randomized complete block design with three replications. The main block is the rubber clones, and the subblocks are fertilization rate and ethephon stimulation. The rubber clones for this research were GT 1, BPM 24, PB 260, and IRR 112. The different fertilization rates used in the experiment were control (no fertilizer), 50% recommended rate (50 RR), 100% recommended rate (100 RR), and 150% recommended rate (150 RR). Ethephon stimulation was applied every two months during the observation period with a rate of S/2 d3 ET2.5% 6/y. The observed parameters included: latex yield, physiological latex (sucrose, inorganic phosphorus, and thiol), and tapping panel dryness. Results showed that rubber yields, such as latex production and dry rubber content, increased by 10%–16% with fertilization and ethephon stimulation. Latex characteristics, including thiol, inorganic phosphate, and sucrose, remained within their optimal ranges, with thiol levels increasing from 0.11 to 0.29 mM, inorganic phosphate from 7.29 to 1.58 mM, and sucrose from 0.42 to 7.12 mM upon fertilization.
Optimizing the Application of Complete Microfertilizer in Fertigation for Cayenne Pepper (Capsicum frutescens L.)
Cayenne pepper (Capsicum frutescens) is one of the important horticultural commodities in Indonesia. According to Central Statistics Agency data, annual consumption has been rising amid fluctuating production, including a 37.68-thousand-ton decline in 2023 compared with 2022. Cayenne pepper requires a specific nutrient profile to achieve optimal yields. Micronutrients, including boron, copper, iron, manganese, molybdenum, and zinc, are vital for photosynthesis, flower development, and nutrient uptake; deficiencies impair growth, fruit quality, and disease resistance, underscoring the need for balanced fertilization. Micronutrient deficiencies can reduce plant growth, fruit quality, and disease susceptibility. Research on micronutrient provision in cayenne pepper plants remains limited. This research aims to determine the most effective method of nutrient application for cayenne pepper plants. The design used was a single-factor randomized group design. The results of the study demonstrate that micronutrient applications can increase the height and diameter of cayenne pepper stems, with foliar spray applications yielding the best response in terms of vegetative parameters. However, micro-nutrient application has not significantly affected the yield and yield components of cayenne pepper.
Fruit and Seeds Development and Seed Germination of Andaliman Pepper (Zanthoxylum acanthopodium DC.)
Andaliman is a species found in the Lake Toba region of North Sumatra, Indonesia. To determine its optimal harvest time and the length of its physiological maturity, it is necessary to observe fruit development in new locations outside its natural habitat. Andaliman seeds are known for their low germination rates and are classified as endospermic seeds. This study aims to analyze the stages of fruit and seed development, evaluate the effects of seed treatments, and identify the most effective germination test methods for andaliman seeds. Seeds were treated with a 50% H2SO4 solution for 15 min and with a 200 ppm GA3 + 100 ppm kinetin solution for 48 hr. The seeds were then tested using pleated paper and top paper media to assess germination response. Changes in fruit coloration indicated various stages of development: intense yellowish-green at 17 weeks after anthesis, deep yellowish-green at 20 weeks, deep red at 23 weeks, and dark greyish-yellowish-brown at 26 weeks. During development, some fruits experienced embryo abortion, resulting in many empty or wrinkled seeds. The seeds reached physiological maturity at 23 weeks after anthesis, as indicated by a deep red fruit color, increased seed dry weight, and enhanced germination and seed growth rates. The treatment with GA3 and kinetin yielded the highest germination rate of 20%, with the pleated paper method proving to be the most effective for germination testing.
Potential of Silybum marianum Aqueous Extract to Inhibit Rhizoctonia solani Growth and Pathogenesis
The present study evaluated the effects of a cold aqueous extract of milk thistle (Silybum marianum) on the growth of the soil-borne pathogen Rhizoctonia solani and on wheat seed germination and seedling development. In vitro assays demonstrated that the extract significantly inhibited fungal growth, with concentrations up to 7.5% completely preventing proliferation. Pot experiments further revealed that soil treated with both R. solani biomass and its culture medium, particularly in the presence of milk thistle extract, resulted in a drastic reduction in wheat seed germination to 30% and complete seedling mortality within 10 days. Notably, when fungal biomass and its medium were treated with increasing concentrations of milk thistle extract (2.5%–10%), wheat seed germination rates improved markedly, ranging from 83% to 93%. In comparison, seedling death decreased from 16% to 10%. Furthermore, seedlings grown under these conditions exhibited significant increases in shoot and root length, as well as overall biomass, compared with controls grown on potato dextrose agar (PDA) alone. These results suggest that milk thistle extract may serve as an effective pre-planting seed treatment, enhancing wheat germination and seedling vigor while reducing susceptibility to Rhizoctonia solani during early developmental stages.
Improved Performance of SiDREB2-SNAP Marker in Foxtail Millet by Optimum Primer Concentration, PCR Cycle, and DNA Polymerase Specificity
Foxtail millet (Setaria italica L. Beauv.) is an emerging carbohydrate-producing crop. It is considered a climate-resilient crop due to its tolerance to abiotic stresses. Breeding for abiotic-tolerant crops requires powerful tools such as molecular markers. The single-nucleotide amplified polymorphism (SNAP) marker, developed from a single-nucleotide DNA variation at a specific location in the plant genome, is a simple yet powerful PCR-based marker widely used in phenotype-related selection. A SiDREB2-based SNAP marker was previously developed based on a base variation at the 558th base pair (an A/G transition) in the SiDREB2 gene and used to estimate the drought tolerance in foxtail millet. However, the specificity of the marker depends on technical aspects, including the type of DNA polymerase used, primer concentration, and the number of PCR cycles. Here, we reported that non-specific and false positive amplicons can be eliminated by utilizing DNA polymerase with no 3’ to 5’ proofreading activity and reducing the final primer concentration to 1.25 μM. PCR cycle number 25 yielded the optimum specificity, while increasing the cycle to 30 resulted in false positive results. Altogether, our results showed that technical optimization is necessary for improving the specificity of the SNAP marker.
Improvement of Chlorophyll, Antioxidant Properties, and Biomass Yield in Sweet Basil (Ocimum basilicum L.) Using Chitosan at Various Growing Stages
Sweet basil (Ocimum basilicum L.) is known for its numerous health-promising antioxidant phytochemicals and is primarily used in nutritive, medicinal, and cosmetic products. Previous attempts to increase the antioxidant content of sweet basil were associated with disadvantages, including ecological problems, reduced biomass yield, and increased cost. Alternatively, the current study aimed to improve selected antioxidants and biomass yield by using chitosan as an organic and cost-effective growth promoter. In this experiment, a total of four different concentrations of chitosan were applied ( 0%, 0.2%, 0.4%, and 0.6% v/v) at two different growing stages: early growth stage (GS1: 45-day-old plant), late growth stage (GS2: 65-day-old plant), and at both growth stages (known as GS3: 45 & 65-day-old plants). Results showed that plants treated with 0.4% chitosan at GS1 reached the highest chlorophyll a (4.33 mg/cm2), chlorophyll b (2.50 mg/cm2), total chlorophyll (6.84 mg/cm2), total leaf area (2234.31 cm2), total dry biomass (22.72 g per plant), total flavonoid content (33.23 mg QUE/g DE) and DPPH inhibition (92.34%) compared to other treatments. Based on the yield and phytochemical content, it is recommended to apply chitosan at 4% on the 45-day-old plant.
The Potential of Metarhizium anisopliae (Metsch.) Sorokīn as the Biocontrol Agent Against Cacao Pod Borer (Conopomorpha cramerella Snellen)
Metarhizium anisopliae (Metsch.) Sorokīn is an entomopathogenic fungus with broad bio insecticidal potential, widely recognized for its role in sustainable pest management. This review examines the taxonomy, pathogenesis, infection symptoms, environmental requirements, host specificity, and dual role as both a biocontrol agent and an endophyte. Special emphasis is placed on its efficacy against the cacao pod borer (Conopomorpha cramerella Snellen), a significant pest in Southeast Asia that causes yield losses exceeding 50% in cacao plantations. Laboratory and semi-field studies report larval mortality rates of up to 80%–90% under controlled conditions. However, field-level efficacy varies due to environmental factors such as temperature, relative humidity, UV exposure, and soil characteristics. The review also discusses formulation strategies, including conidial suspensions and granular formulations, that improve fungal persistence and infection success. Despite promising outcomes, the effectiveness of M. anisopliae is influenced by strain variability, local adaptation, and integration with cultural practices. Understanding these dynamics is crucial for optimizing the application of this approach in integrated pest management (IPM) systems and advancing sustainable cacao production.
Effect of GA3 Application on the Germination of 5-Year Stored Bambara Groundnut (Vigna subterranea (L.) Verdc.)
Bambara groundnut (Vigna subterranea (L.) Verdc.) is a leguminous crop originating from North Africa, valued for its high protein and carbohydrate content, as well as its ability to adapt to marginal environments. These characteristics make it a promising candidate to support food and nutritional security, particularly in tropical regions. However, its cultivation and seed quality management remain limited, requiring strategies to improve germination and seedling establishment. Gibberellic acid (GA3) is a plant growth regulator widely known to stimulate seed germination and enhance vigor. This study aimed to assess the effect of GA3 on the germination performance of Bambara groundnut seeds stored for five years. Three genotypes (SS 3.4.2, BBL 1.1, and TVSU 8.6) were treated with GA3 at concentrations of 0, 75, 150, and 225 ppm, and germination and vigor parameters were evaluated. The results showed that GA3 application improved the performance of aged seeds, with 225 ppm identified as the most effective dose. Genotype SS 3.4.2 responded particularly well at this concentration, while BBL 1.1 consistently exhibited superior overall performance across treatments. These findings highlight the potential of GA3 to mitigate the adverse effects of seed aging and enhance seedling establishment. The application of GA3 represents a practical approach for improving the viability of stored seeds.
Purple Cleome (Cleome rutidosperma) Growth, Yield, and Total Flavonoid Under Different Media Compositions and Harvesting Frequencies
Purple cleome (Cleome rutidosperma) is a medicinal plant known for its flavonoid content, which confers multiple pharmacological benefits. However, cultivation methods to optimize both biomass production and bioactive compound accumulation remain underdeveloped. This study aimed to assess the influence of planting media composition and harvesting frequency on the growth, yield, and total flavonoid concentration of purple cleome. The experiment was conducted in Gunung Batu, Bogor, Indonesia, from January to April 2025, employing a two-factor randomized block design. The first factor was planting media composition, with four treatments: 100% soil (0) and soil mixed with cow manure at ratios of 1:1, 1:2, and 1:3 (v/v). The second factor was harvesting frequency, with two levels: A single harvest at 8 weeks after planting (WAP) and two harvests at 4 and 8 WAP. Results indicated that all tested media compositions supported plant growth effectively. Notably, total flavonoid concentration was significantly higher at 4 WAP compared to 8 WAP. Moreover, cumulative flavonoid yield from two harvests was significantly greater, reaching 5,639.80 mg quercetin equivalents (QUE) per plant dry weight, compared to 1,456.50 mg QUE per plant from a single harvest. These findings suggest that harvesting at multiple intervals enhances flavonoid yield in purple cleome cultivation.
Coffee (Coffea spp.) Production Systems, Postharvest Innovations, and Quantitative and Agroecological Dynamics in the Davao Region, Philippines
Coffee (Coffea spp.) is a globally significant tropical plantation crop, and the Davao Region in the Philippines is one of the country’s most dynamic production zones, thanks to its favorable volcanic soils, diverse microclimates, and evolving value chain ecosystems. With an estimated 15,821.68 ha under cultivation, the region supports all major Coffea species. Coffea arabica thrives above 1,000 m asl in highland zones such as Balutakay, Maragusan, and upland Davao City; Robusta dominates lower elevations, while Liberica and Excelsa occupy smaller areas as complementary tropical crop components. Agroecological sustainability is promoted through shade-based agroforestry systems that enhance biodiversity, soil fertility, and climate resilience. Postharvest innovations such as natural, honey, and micro-lot fermentation, alongside the expansion of community-based roasting facilities, have enabled specialty-grade production and improved access to premium domestic and international markets. Emerging trends presented at the Davao Regional Coffee Expo (DRCE) 2025 include the increased adoption of climate-resilient genetic varieties artificial intelligence-based plantation monitoring, gender-inclusive entrepreneurship, and youth participation in value-added roles such as roasting, cupping, and barista craftsmanship. However, persistent constraints, including aging plantations, low productivity, limited seedling supply, postharvest infrastructure gaps, market dependency on intermediaries, and inconsistent institutional support, continue to limit the sector’s tropical crop competitiveness. This status report consolidates insights on production systems, agroecological management, postharvest innovations, and socio-economic challenges to provide a strategic outlook for strengthening coffee as a sustainable tropical plantation crop within the Davao Region and similar highland environments in Southeast Asia.
Effect of Shape and Size of Purple Nutsedge (Cyperus rotundus L.) Tuber Bioherbicide Granules on the Germination of Weed and Crop Seeds
The use of synthetic herbicides is an effective way to control weeds, but their widespread use has negative environmental impacts. A bioherbicide made from purple nutsedge tubers can be an alternative for weed control. Purple nutsedge’s tuber contain allelopathy compounds that can inhibit the growth of other plants (weeds). This study aims to evaluate the response of various shapes and sizes of bioherbicide granules made from purple nutsedge’s tuber in suppressing the germination of weed seeds and crop seeds. The experiment used a completely randomized design one factor and eleven treatments: control without herbicide treatment, synthetic herbicide active ingredient oxyfluorfen 240 g/L, purple nutsedge’s tuber powder bioherbicide without carrier, very small round granule bioherbicide, small round granule, medium round granule, large round granule, very small cylindrical granule, small cylindrical granule, medium cylindrical granule, and large cylindrical granule. Each treatment was tested on four species: Bidens pilosa and Cynodon dactylon (weeds), cucumber, and rice (crops). The experimental results showed that the application of purple nutsedge’s tuber-based bioherbicides exerts a noticeable influence on several germination parameters. The smaller the bioherbicide granule, the higher the germination inhibition rate. Very small, round-shaped granule bioherbicides showed greater effectiveness in suppressing seed sprout percentage, reducing growth rate, increasing the percentage of abnormal sprouts, and inhibiting plumula and radicle growth.
Cryopreservation of Terap (Artocarpus elasticus Reinw. ex. Blume) Seeds: Viability and Structural Characterization
Terap (Artocarpus elasticus Reinw. ex Blume) is an underutilized fruit tree native to Indonesia, valued both for its edible fruit and its diverse applications in traditional medicine. Terap seeds are recalcitrant, so cryopreservation is the most effective method for their long-term preservation. This study aimed to determine the optimal loading and vitrification times for cryopreservation to maintain seed viability. A factorial, completely randomized design was employed with two factors: loading time (0 and 20 min) and vitrification time (0, 30, and 60 min). Seed viability after loading and vitrification treatment with or without freezing in liquid nitrogen was evaluated using tetrazolium chloride (TTZ) and germination tests. Results indicated that the loading and vitrification treatments did not yet improve the viability of terap seeds after cryopreservation, as determined by the TTZ and germination tests. The TTZ test showed that the viability of all treated seeds decreased, regardless of whether they were frozen in liquid nitrogen. Germination tests revealed that all treated seeds without freezing had reduced germination, while none of the seeds treated with freezing germinated. Structural analysis indicated that freezing alters cell degradation, likely due to the formation of ice crystals and mechanical stress. To improve the success of terap seed cryopreservation, future efforts should focus on optimizing exposure times, reducing PVS2 toxicity, and enhancing cryoprotectant penetration by removing the seed coat or using the embryo axis as an explant.
Economic Viability and Ecological Outcomes of Organic Horticulture: Evidence from Highland Farming Communities in Bali, Indonesia
Organic horticulture is an essential component of sustainable agriculture, offering agronomic, ecological, economic, and social benefits. This study investigates the economic viability and ecological outcomes of organic horticultural practices among highland farming communities in Bali, Indonesia. Utilizing a case study of certified organic farmer groups, data were collected via interviews, field observations, and secondary sources. Analysis included market trends, cost-benefit ratios, productivity, and environmental indicators. Findings show that organic horticulture enhances soil fertility with compost and manure, and manages pests through crop rotation, intercropping, and plant derived pesticides. Economically, organic horticulture is highly profitable, with a benefit-cost (B/C) ratio of 14.18, driven by strong consumer demand for pesticide-free produce in urban and tourist markets. Environmentally, organic farming reduces chemical contamination, boosts soil organic matter, and strengthens agroecosystem resilience. Socially, it promotes cooperative farming, knowledge sharing, and community engagement. Challenges include higher input costs, complex certification processes, and limited access to organic farming technology. This research’s novelty is its integrative assessment of agronomic productivity, environmental sustainability, and economic feasibility in a unique tropical context, offering a holistic sustainability model. Findings contribute to organic agribusiness theory, sustainable development, and resilient food system policymaking.
Effects of Chicken Manure Dose and Application Timing on the Productivity and Microbiological Safety of Lettuce (Lactuca sativa L.)
Organic lettuce is widely regarded as a healthier alternative because it is free of chemical contaminants. Chicken manure is commonly used as an organic fertilizer because of its high nutrient content, which is readily available to plants. However, applying manure poses a risk of pathogenic bacterial contamination. This study aimed to evaluate the effects of different chicken manure doses and application times, as well as their interactions, on lettuce (Lactuca sativa L.) productivity and microbiological safety. The experiment was conducted from March to May 2023 in Cianjur, West Java, using a factorial randomized block design (RBD) with three replications. Treatments included a control and two factors: (1) manure dose (10, 20, and 30 t/ha), and (2) application times (1, 2, and 3 weeks before transplanting). Microbiological analysis of harvested lettuce leaves was performed in the laboratory to assess contamination levels of Escherichia coli, Salmonella spp., and Shigella spp. Manure doses significantly influenced all growth and yield parameters but had no significant effect on quality variables, including flavonoid, nitrate, and total chlorophyll content. Application times showed no significant effect on any measured parameter. The interaction between dose and time was also not statistically significant for most variables. The highest productivity and marketable yield were observed at the 30 t/ha dose. Salmonella spp. was not detected in any samples; however, E. coli and Shigella spp. were present in all samples at levels exceeding the Indonesian National Standard (SNI) for food safety. In addition to the required dose of chicken manure, to minimize microbial contamination, fully decomposed manure is recommended for application, as it can be applied to land shortly before planting. The use of microbial-free water for washing vegetables is recommended, including in further research.
Water and Crop Management Technologies: Physiological Response and Yield of Biofortified Rice
Biofortified rice has emerged as one of the most promising strategies to enhance the micronutrient content of staple crops, offering a practical pathway to reduce stunting and improve nutritional security. In response to the challenges posed by climate change, water scarcity, and the need for more efficient production systems, this study examined the effects of water- and crop- management technologies on the physiological performance and yield of biofortified rice. A factorial randomized complete block design compared continuous flooding and alternate wetting and drying (AWD) irrigation with two crop management systems: conventional and a new technology. The AWD system enhanced photosynthesis without significantly affecting transpiration or stomatal conductance, indicating improved carbon assimilation and more efficient water use. Both AWD and the new technology individually increased dry grain yield per clump, while their combination produced heavier grains, higher productivity, greater 1000-grain weight, and improved water-use efficiency compared with other treatments. Although yield differences were not statistically significant, the consistent upward trends indicate synergistic potential when nutrient management is optimized. Overall, integrating AWD irrigation with new technology crop management can enhance resource efficiency in biofortified rice cultivation while maintaining yield stability under water- limited conditions.
Effect of Herbicides and Azotobacter chroococcum Bacteria on Soil Bacterial Growth, Growth, and Yield of Maize (Zea mays L.)
To obtain high yield, herbicides are applied to food crops, including maize. It is important to adopt sustainable agricultural practices to enhance soil fertility by bacterial inoculation. Two experiments were conducted at the Faculty of Agriculture, University of Kufa, Iraq, to investigate the effects of glyphosate and 2,4 D herbicides on soil bacterial activity, growth, and maize (Zea mays L.) yield. A laboratory experiment, using a completely randomized design, evaluated the response of Azotobacter chroococcum and Bacillus subtilis to varying herbicide concentrations. Bacterial populations were quantified after 24 hr of incubation to determine the minimum inhibitory concentration within the nutrient medium. Subsequently, a f ield experiment was conducted in a sandy loam soil during the 2024–2025 autumn season using a randomized complete block design; the factors included bacterial inoculation and herbicide application at three rates: half, full (recommended), and double the recommended dose. Results indicated that high concentrations of glyphosate and 2,4-D significantly reduced total bacterial counts to 3.50 × 10⁶ CFU/g dry soil. Conversely, inoculation with A. chroococcum increased the population to 18.83 × 10⁶ CFU/g, with the interaction between A. chroococcum and the recommended glyphosate dose achieving the highest density of 37.00 × 10⁶ CFU/g. Regarding plant physiology, inoculation increased total chlorophyll content from 1.33 to 1.68 mg/g and leaf area from 415.34 to 879.71 cm2 per plant. Leaf nutrient concentrations also improved significantly; nitrogen rose from 1.18% to 2.08%, phosphorus from 0.17% to 0.23%, and potassium from 1.26% to 1.50%. These improvements were reflected in vegetative growth and productivity; the dry weight of the vegetative system increased from 199.25 g in uninoculated controls to 278.36 g in the full-recommended glyphosate treatment with inoculation. Total grain yield ranged from 12.31 to 16.29 t/ha, with A. chroococcum inoculation alone reaching a mean yield of 15.57 t/ha.
Biopesticide Potential of Laurus nobilis and Inula viscosa Essential Oils for the Management of Tomato Leaf Miner (Tuta absoluta)
The tomato leaf miner, Tuta absoluta, is one of the most destructive tomato pests worldwide. The use of chemical pesticides can improve yield and fruit quality; however, it poses serious risks to human health and the environment. Consequently, research efforts are increasingly focusing on sustainable, eco-friendly pest management strategies, including the use of essential oils as biopesticides. This study evaluates the insecticidal activity of Laurus nobilis and Inula viscosa essential oils against the four larval instars of T. absoluta. Essential oils were assessed using a contact toxicity assay, with each dose tested across all larval instars and compared with an untreated control. Lethal doses (LD50 and LD90) were estimated using Probit regression analysis. The bioassays showed that both essential oils exhibited significant larvicidal activity with dose- and stage-dependent mortality. Early larval instars required lower doses to achieve 50% and 90% mortality (10, 20, and 30 µl for I. viscosa; 3, 5, and 10 µl for L. nobilis), whereas later instars were more tolerant and required higher doses. Complete mortality of all four larval instars was obtained at 100 µl of I. viscosa and 30 µl of L. nobilis. Overall, these findings demonstrate the larvicidal potential of these essential oils and support their use as biopesticides within integrated pest management programs in agriculture. To our knowledge, this is the first report of the larvicidal activity of the essential oils from I. viscosa and L. nobilis against T. absoluta in Algeria.
Using Bioremediation to Reduce Groundwater Salinity
A study was conducted to evaluate the effectiveness of microorganisms in reducing groundwater salinity and to identify the most effective organisms. A laboratory experiment was performed using a completely randomised block design with a factorial arrangement, with four treatments and three replicates, yielding 12 experimental units for the biological treatment of groundwater. This experiment included the sequential addition of microorganisms (control, Providencia rettgeri, Bacillus amyloliquefaciens, and Rhizoctonia solani) to groundwater with a salinity of 13108 µS/cm, with continuous monitoring of changes in EC, pH, and other water chemical properties. Providencia rettgeri achieved the highest temperature on June 26th, reaching 29.0 °C, whereas the control treatment recorded a lower temperature on the same date. Meanwhile, Bacillus amyloliquefaciens outperformed the control, achieving the highest nitrogen content in the treated water at 1499 mg/L, compared with the control at 1372 mg/L. Rhizoctonia solani excelled by recording the lowest electrical conductivity and pH for the treated water on 6/25, at 11607 ds/cm and 6.73, respectively, compared to the control treatment, which recorded the opposite in both characteristics.
Effects of Gibberellin and Melatonin Foliar Sprays on Basil Chemical Composition and Volatile Oil Yield under Water Stress
This study investigated the potential of exogenous gibberellic acid (GA3) and melatonin (MT) to mitigate the adverse effects of drought stress on basil (Ocimum basilicum L.). Conducted in 2022 at the University of Baghdad, Iraq, the experiment employed a split-plot design within a completely randomized block design. Three irrigation intervals (3, 5, and 7 days) were assigned to the main plots, while subplots received a factorial combination of the plant growth regulator gibberellic acid (GA3; 0, 100, and 200 mg/L) and melatonin (0, 20, and 40 mg/L). Results indicated that moderate water stress with a 5-day irrigation interval significantly enhanced leaf nitrogen, phosphorus, and potassium nutrient content, total phenolic content, and volatile oil yield compared with the 3-day and 7-day irrigation intervals. The application of 200 mg/L GA3 and 40 mg/L melatonin consistently yielded the highest values for all physiological and chemical parameters. Significant double- and triple-interactions suggest that the synergistic application of GA3 and melatonin effectively improved basil secondary metabolism under water-limited conditions. These findings highlight a strategic approach for optimizing essential oil production in arid environments.