Evaluation of some organic ameliorants in mitigating drought stress and enhancing agronomic and physiological traits in Watermelon (Citrullus lanatus L.)
Doctoral Program of Agricultural Science, Faculty of Agriculture, Universitas Sebelas Maret, St. Ir. Sutami No.36A, Surakarta 57126, Central Java, Indonesia
Department of Agrotechnology, Faculty of Agriculture, Universitas Sebelas Maret, St. Ir. Sutami No.36A, Surakarta 57126, Central Java, Indonesia
Center for Research and Development of Biotechnology and Biodiversity, Universita Sebelas Maret. St. Ir. Sutami No.36A, Surakarta 57126, Central Java, Indonesia
Abstract
Water hyacinth bokashi, manure, and rice husk biochar are organic ameliorants known for their potential to improve productivity, particularly under drought stress. This study aimed to evaluate the effectiveness of some important organic ameliorants in reducing the negative effects of drought on watermelon (Citrullus lanatus L.). A factorial randomized block design (FRBD) was used, involving two factors: (1) combination of organic ameliorants —water hyacinth bokashi + manure (BoM), water hyacinth bokashi + rice husk biochar (BoBi), manure + rice husk biochar (MBi), and a mixture of all three (BoMBi); and (2) four levels of drought stress (100%, 75%, 50%, and 25% of field capacity, FC). The results showed that under optimal moisture conditions (100% FC), BoBi and BoMBi treatments significantly enhanced plant height, leaf area, and fruit weight, indicating their strong growth-promoting effects. However, under moderate to severe drought stress (50% and 25% FC), the ameliorants provided limited mitigation, with reductions in stomatal size and only modest improvements in growth. Notably, the highest total soluble solids (TSS) were observed under 25% FC in BoMBi50 (12.00°Brix) and MBi25 (11.33°Brix), suggesting a stress-induced increase in fruit quality. Overall, the study identifies BoBi and BoMBi as the most effective treatments for enhancing watermelon productivity under normal to moderate drought conditions. These combinations show potential for practical application by farmers, especially in areas with intermittent water availability. However, under severe drought, their effectiveness is limited, highlighting the need for additional drought mitigation strategies.
Submitted: 18/03/2025 | Revised: 31/05/2025 | Accepted: 18/06/2025
Pages 860-869 | Full Text PDF| https://doi.org/10.21475/ajcs.25.19.08.p02
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Agronomic performance of melon cultivars in the Amazon Savannah environment of Brazil
Edgley Soares Silva, Roberto Dantas de Medeiros, José de Anchieta Alves de Albuquerque, Musibau Oyeleke Azeez*, João Luiz Lopes Monteiro Neto, Wellington Farias Araújo, Ozimar de Lima Coutinho, Laura Soliane Cruz Braz, Hananias dos Santos Cruz, Felipe Fernandes Dias
Instituto de Educação e Inovação (IEDi), Av. Ville Roy, 1908. Bairro Caçari, CEP: 69307-970.
Boa Vista, RR. Brazil
Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA), BR 174, Km 8, Distrito Industrial Caixa Postal 133, CEP: 69301-970. Boa Vista, RR. Brazil
Programa de Pós-Graduação em Agronomia (POSAGRO), Universidade Federal de Roraima (UFRR) em parceria com a EMBRAPA-RORAIMA, BR 174, Km 12, Campus do Cauamé, Bairro Monte Cristo, CEP: 69.301-970. Boa Vista, RR. Brazil
Department of Soil Science and Land Resources Management, Obafemi Awolowo University, Ile-Ife. Nigeria
Curso de Agronomia, Centro de Ciências Agrárias (CCA), Universidade Federal de Roraima (UFRR), BR 174, Km 12, Campus do Cauamé, Bairro Monte Cristo, CEP: 69.301-970. Boa Vista, RR. Brazil
Abstract
An experiment was conducted with the objective of evaluating the agronomic performance of eight melon cultivars under the soil and climatic conditions of the Amazon savannah. The experimental design was a randomized complete block with four replications and five plants per plot. The treatments consisted of eight cultivars: Eldorado 300, Favo, and Goldex (Yellow type), Hales Best Jumbo, Imperial, and Rock (Cantaloupe type), Gaúcho (Caipira type), and Juazeiro (Piel de Sapo type). Productive characteristics, seed characteristics, and fruit quality were evaluated. The highest commercial yields were obtained with the cultivars Juazeiro (27,551.75 kg ha⁻¹), Rock (24,170.0 kg ha⁻¹), and Imperial (24,116.75 kg ha⁻¹), respectively. Seed characteristics varied depending on the cultivar, with the highest seed quantity in the 'Favo' cultivar and the highest seed mass in 'Eldorado 300'. Regarding fruit quality, the cultivars Juazeiro and Goldex exhibited greater pulp firmness and higher soluble solids content, which meet the qualitative demand of both domestic and international markets. The cultivars Juazeiro, Rock, and Imperial demonstrated high potential for cultivation under the soil and climatic conditions of the Amazon savannah. It was concluded that the soil and climatic conditions of the Amazon Savannah favored productive characteristics and fruit quality for different analyzed cultivars.
Submitted: 24/03/2025 | Revised: 22/05/2025 | Accepted: 06/06/2025
Pages 870-875 | Full Text PDF| https://doi.org/10.21475/ajcs.25.19.08.p03
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Maize under heat stress in lowland tropics: Learnings and the way forward
Sara Fatma*, Hema Singh, Pawan Kumar Singh, M.T. Vinayan, P.H. Zaidi*
Department of Botany, Banaras Hindu University, Varanasi-221 005, Uttar Pradesh, India
Department of Plant Breeding and Genetics, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi-221 005, Uttar Pradesh, India
Global Maize Program, International Maize and Wheat Improvement Centre (CIMMYT), ICRISAT campus, Hyderabad-502324, India
Abstract
The two main factors contributing to heat stress are higher temperatures and low relative humidity at high temperatures. Growing almost year-round, maize crops in the lowland tropics are exposed to rising temperatures, negatively affecting crop productivity, especially under rainfed conditions. Studies have identified several morphological, biochemical, and physiological changes in field crops, including maize under heat stress. Among these, a few changes enable plants to adapt to heat stress (stress-adaptive traits), while others exhibit adverse effects of stress (stress-responsive traits). At the biochemical level, heat stress results in increased levels of superoxide dismutase (SOD) and catalase enzyme activities in cells, as well as elevated levels of Heat Shock Proteins (HSPs). Options have been identified to mitigate the effects of heat stress on maize crops, such as suitable planting time to avoid a high-temperature regime coinciding with critical crop growth stages, furrow sowing, and frequent irrigation to maintain a vital minimum relative humidity in the air. Efforts on genetic improvement for heat tolerance in maize resulted in the development of new heat-tolerant maize hybrids, which can thrive at temperatures beyond threshold limits for tropical maize and suffer relatively less under heat stress. However, the challenge remains mainly due to low genotypic variability for stress in elite maize germplasm and strong genotype-by-environment interaction under heat stress, resulting from varying vapor pressure deficits (VPD) at high temperatures. Therefore, diving deeper and exploring local landraces and wild accessions is necessary to explore wider genotypic variation for heat stress tolerance in tropical maize. Recent advances in genomics-assisted breeding may help identify genomic regions associated with heat stress tolerance in maize and target the introgression of validated genomic regions into elite maize germplasm to develop the next generation of maize cultivars with improved, stable performance under heat stress conditions. In this article, we reviewed the progress and key findings on various aspects of research on heat stress in field crops, with an emphasis on tropical maize, which may help refine the approaches of research programs working on heat stress and aiming to develop crop varieties with improved tolerance to heat stress.
Submitted: 25/03/2025 | Revised: 24/05/2025 | Accepted: 18/06/2025
Pages 876-886 | Full Text PDF| https://doi.org/10.21475/ajcs.25.19.08.p04
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Optimizing spatial arrangements and planting schedules for cassava-watermelon intercropping in the Amazon Savannah
Edgley Soares Silva, Roberto Dantas de Medeiros, José de Anchieta Alves de Albuquerque, João Luiz Lopes Monteiro Neto, Musibau Oyeleke Azeez*, Ademar Bezerra Alves, José Maria Arcanjo Alves, Valdinar Ferreira Melo, Maria Beatriz Bernades Soares, Everton Luis Finoto
Programa de Pós-Graduação em Agronomia (POSAGRO), Universidade Federal de Roraima (UFRR) em parceria com a EMBRAPA-RORAIMA, BR 174, Km 12, Campus do Cauamé, Bairro Monte Cristo, CEP: 69.301-970. Boa Vista, RR. Brazil
Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA), BR 174, Km 8, Distrito Industrial Caixa Postal 133, CEP: 69301-970. Boa Vista, RR. Brazil
Agência Paulista de Tecnologia dos Agronegócios (APTA), Rodovia Washington Luiz, Km 372, Caixa Postal 24, CEP: 15830-000. Pindorama, SP. Brazil
Abstract
The intercropping system increases the productive potential of crops and improves land use efficiency. However, it is necessary to arrange the plants so that the spatial distribution and planting time are as favorable as possible. The objective of this study was to evaluate the agronomic performance of the intercropping of cassava with watermelon in different spatial arrangements and planting time. The experiment was conducted from December 2020 to August 2021 in a typical Amazonian savannah area, and the soil of the experimental area is classified as Typic Hapludox. The experimental design was randomized blocks, arranged in a split-plot scheme, with four replications. Four cassava planting times were tested in the plots: 0, 10, 20 and 30 days after watermelon sowing, and five arrangements were tested in the subplots; Cassava and watermelon were planted in various arrangements, including single and double rows, on the same or opposite sides of each other: I) cassava planted in a single row (4.0 m x 1.0 m), on the same side of the watermelon sowing furrow; II) cassava planted in a single row (3.5 x 1.0 m), on the opposite side of the watermelon sowing furrow; III) cassava planted in double rows (3.5 x 1.0 x 0.5 m), on both sides of the watermelon sowing furrow, IV) cassava planted in single rows, in double rows (3.5 x 1.0 x 0.5 m), on both sides of the furrow and V) watermelon sown in single rows (4.0 m x 1.0 m). The irrigation was carried out using furrows 40.0 m in length, with a slope of 1.0% and an average flow rate of 0.5 L s⁻¹. The spatial arrangements and planting times did not interfere with the watermelon crop and were capable of maintaining high productive yield and desirable fruit quality. Under the experimental conditions, watermelon recorded an average productivity among the treatments corresponding to 47,735.78 kg ha-1. This value was 53.82% and 13.96% higher than the productivities of Roraima and Brazil, respectively. As for the cassava productivity, although the variations were statistically similar, we strongly recommend planting in a single row on the same side of the watermelon sowing furrow, with which we obtained a productivity of approximately 18,000 kg ha-1.
Submitted: 01/03/2025 | Revised: 05/05/2025 | Accepted: 06/06/2025
Pages 887-894 | Full Text PDF| Supplementary Data PDF| https://doi.org/10.21475/ajcs.25.19.08.p375
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Microorganisms for increasing sugarcane productivity: a way to complement and reduce chemical fertilization
Willyan Júnior Adorian Bandeira, Ivan Ricardo Carvalho*, Lays Garcia Meireles, Luis Fernando Maranho Watanabe, Lucas Moraes Santos
Department of Agricultural Studies, Regional University of the Northwest of the State of Rio Grande do Sul (UNIJUÍ), Ijuí, Brazil
Research and Development, Total Biotecnologia Indústria e Comércio SA, Santo Antônio de Posse, Brazil
Abstract
This study evaluated the efficiency and agronomic feasibility of four inoculants - Azotrop, Biofree, BTP 143-20, and BTP 167-20 - in the development and productivity of sugarcane crops as a complement to chemical fertilization across five Brazilian locations from 2022 to 2023. The experimental design used was a randomized complete block design, with 14 treatments and four replicates in the experiments with Biofree, BTP167-20 and BTP143-20 and eight treatments in the experiment with Azotrop. Plant height, stalk diameter and stalk productivity variables were measured. The variance components and genetic parameters were estimated using Restricted Maximum Likelihood (REML), with the results supported by the Deviance analysis at 5% probability using the chi-square test. The Best Linear Unbiased Predictor (BLUP) was used to determine the effect of treatments on the measured traits and ranked. Results revealed strong environmental effects on plant height and stalk diameter, while productivity was more stable across environments. Inoculation with BTP167-20 represents the greatest efficiency and has agronomic feasibility for sugarcane crops, with superior performance to inoculants already on the market and capable of reducing the need for nitrogen and phosphate chemical fertilization by up to 25%, acting in a complementary way in the efficiency of use and absorption of nutrients.
Submitted: 16/04/2025 | Revised: 10/06/2025 | Accepted: 11/06/2025
Pages 895-902 | Full Text PDF| Supplementary Data PDF| https://doi.org/10.21475/ajcs.25.19.08.p17