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The aim of the current study was to assess the potency of the exopolymeric substances (EPS)-secreting purple non-sulfur bacteria (PNSB) on rice plants on acidic salt-affected soil under greenhouse conditions. A two-factor experiment was conducted following a completely randomized block design. The first factor was the salinity of the irrigation, and the other factor was the application of the EPS producing PNSB (Luteovulum sphaeroides EPS18, EPS37, and EPS54), with four replicates. The result illustrated that irrigation of salt water at 3–4‰ resulted in an increase in the Na+ accumulation in soil, resulting in a lower rice grain yield by 12.9–22.2% in comparison with the 0‰ salinity case. Supplying the mixture of L. sphaeroides EPS18, EPS37, and EPS54 increased pH by 0.13, NH4+ by 2.30 mg NH4+ kg−1, and available P by 8.80 mg P kg−1, and decreased Na+ by 0.348 meq Na+ 100 g−1, resulting in improvements in N, P, and K uptake and reductions in Na uptake, in comparison with the treatment without bacteria. Thus, the treatments supplied with the mixture of L. sphaeroides EPS18, EPS37, and EPS54 resulted in greater yield by 27.7% than the control treatment.

The objective of this study was to evaluate the antagonistic activity of Trichoderma spp. against wild pathogen Fusarium oxysporum F.28.1A, which causes wilt disease on sesame. Twenty-six isolates of Trichoderma spp. isolated from soil samples were tested to control F. oxysporum F.28.1A. Prescreening showed that five isolates were T-02B1, T-18B2, T-20B1, T-28B1, and T-29A1, based on the lowest values of colony radius of F. oxysporum F.28.1A. The selected isolates were identified by their ITS region as T. yunnanense T-02B1, T. lentiforme T-18B2, T. asperellum T-20B1, T. hamatum T-28B1, and T. hamatum T-29A1, with similarities around 96–100%. The isolates selected were able to produce enzymes including chitinase, exo-β-1,3-glucanase, and endo-β-1,3-glucanase at levels of 0.34–0.44, 0.017–0.034, and 0.032–0.121 UI · ml –1, respectively, which were considered to be a mechanism to prevent the growth of F. oxysporum F.28.1A. The isolates tested were applied in soil pots to prevent damage from F. oxysporum F.28.1A as a following experiment. The greenhouse experiment was arranged in a completely randomized design with 10 treatments, including a negative control, application of only F. oxysporum F.28.1A, application of both F. oxysporum F.28.1A and fungicide chemicals, application of both F. oxysporum F.28.1A and Trichoderma spp. DHCT, application of T. yunnanense T-02B1, application of T. lentiforme T-18B2, application of T. asperellum T-20B1, application of T. hamatum T-28B1, application of T. hamatum T-29A1 and a mixture of the five selected isolates of Trichoderma spp. with their total population equal to that in individual strain application. The results showed that the five mixed isolates of Trichoderma had a synergistic effect on the reduction of the disease’s prevalence by 35% compared to the negative control treatment.

Purpose. Saltwater intrusion affected seriously the livelihood of mangosteen growers in Ben Tre, a coastal province in the Vietnamese Mekong Delta in 2016. This study assesses how saltwater intrusion influenced the livelihood vulnerability of the mangosteen households and communities. Methodology / approach. This study used the United Nations’ Livelihood Vulnerability Index (LVI) and a similar index from the Intergovernmental Panel on Climate Change (LVI-IPCC) using data from 196 interviewed mangosteen growers in Cho Lach district, Ben Tre province in 2016 and 2018. A total of twenty-five (25) indicators are applied to calculate the two indices, using data as exposure to saltwater intrusion and natural hazards (5), socio-demographic factors (11), and sensitivity of health, finance, and source of water for domestic use (9). Results. The analysis results show that mangosteen-growing households had a medium vulnerability in 2016 and 2018 based on both indices. However, they were extremely vulnerable due to saltwater intrusion in 2016, and a high household percentage had a moderate value in the vulnerability index. They did not experience how to respond to saltwater intrusion and received a late warning on saltwater intrusion from the local authorities and media. However, mangosteen-growing households had a quick adaptive behavior to shift to new crops to improve their income in 2018. Originality / scientific novelty. The study provides a set of indicators to assess the vulnerability of this low-vulnerable area based on past studies as well as the actual situation of the study area in 2016 and 2018 to determine what factors influenced the main components, LVI and LVI – IPCC. These indicators represented the characteristics of the rural households in Vietnam and other Asian countries. This research also indicated how LVI and LVI – IPCC results differently and when they should be used. The analysis identified the factors influencing the LVI and LVI – IPCC by levels of saltwater intrusion in different years of 2016 and 2018, two different severe and less severe sites, adaptive and non-adaptive households, and their interaction. Practical value / implications. LVI and LVI-IPCC are good indicators for local and regional assessments on how saltwater intrusion and natural hazards affect households’ and communities’ livelihood and thereby how to guide them to respond promptly in such cases.

Stem-end rot disease has been causing damage to the production of pomelos in Vietnam. The cur-rent study aimed to (i) isolate fungal pathogens causing pomelo stem-end rot disease (PSERD) and (ii) discover Trichoderma spp. that had an antagonistic ability against pathogens under in vitro conditions. Fungi causing PSERD were isolated from pomelo fruits with symptoms of stem-end rot disease and collected from pomelo farms in Ben Tre province, Vietnam. Moreover, 50 fungal strains of Trichoderma spp. also originated from soils of these pomelo farms in Ben Tre province and were dual-tested with the fungal pathogen on the PDA medium. The results demonstrated that 11 pathogenic fungi causing PSERD were isolated from the fruit and showed mycelial growth of roughly 5.33–8.77 cm diameter at 72 h after inoculation. The two fungi that exhibited the fast-est growth, namely, S-P06 and S-P07, were selected. ITS sequencing of the S-P06 and S-P07 fungi resulted in Lasiodiplodia theobromae. All the 50 Trichoderma spp. strains were allowed to antago-nize against the S-P06 and S-P07 strains under in vitro conditions. The greatest antagonistic effi-ciency was found in Trichoderma spp. T-SP19 at 85.4–86.2% and T-SP32 at 84.7–85.4%. The two antagonists were identified as Trichoderma asperellum T-SP19 and T-SP32. The selected strains of Trichoderma asperellum were potent as a biological control for fruit plants.

The aim of the current research was to evaluate the effects of members of purple nonsulfur bacteria (PNSB), Rhodopseudomonas palustris strains of VNW02, TLS06, VNW64, and VNS89, mixed with spent rice straw (SRS) from mushroom cultivation as a carrier on promoting sesame growth and yield, and ameliorating the alluvial soil (AS) fertility in dykes. A 4 × 3 factorial experiment consisting of different levels of the solid PNSB biofertilizer mixture at 0, 3, 4, and 5 t·ha−1 (0, 1.81 × 108, 2.24 × 108, and 2.68 × 108 cells pot−1, respectively), and nitrogen (N) and phosphorus (P) inorganic fertilizer rates (100, 75, and 50 kg·N·ha−1; 60, 45, and 30 kg P2O5·ha−1, respectively) was performed in pots with the sesame variety of ADB1 in the dyked AS. The solid PNSB biofertilizer mixture at at least 3 t·ha−1 significantly enhanced the sesame seed yield by providing higher macronutrients for plants by increasing available N and soluble P concentrations in the soil. The solid PNSB biofertilizer mixture in addition to 75% of the recommended N and P fertilizers produced an equivalent yield in comparison to the utilized 100% of N and P inorganic fertilizers. The solid PNSB biofertilizer mixture in the SRS from the mushroom production reduced at least 25% of N and P chemical fertilizers for gaining the maximal seed yield and enriched soil characteristics for the sustainable black sesame cultivation in the dyked AS.

The present study aimed to identify the abilities of the δ-aminolevulinic acid (ALA) producing purple non-sulfur bacteria (PNSB), Luteovulum sphaeroides W22 and W47, to reduce the Na+ concentration, and to ameliorate the soil fertility, nutrients uptake, growth and yield of rice on the salt-contaminated soil. A two-factor experiment was conducted following a completely randomized block design. The factors were the frequency of applying saline irrigation (zero, one, two, three and four times) and the ALA-producing PNSB supplementation (applying only W22, only W47 and mixed W22 + W47). The results revealed that supplying the PNSB mixture not only reduced the proline content but also increased the plant height, number of panicles per pot, percentage of filled seeds, contents of NH4+, PO43−, total N, P uptake and grain yield. The mixed PNSB application also reduced the Na content and the total Na uptake in plants. L. sphaeroides W22 and W47 decreased the proline content by 31.3% and increased the grain yield by 27.2% in the condition of applying 5‰ saline irrigation four times.

Background: To determine the optimal water irrigation method combined with covering material for Allium chinense growth and yield on acid sulfate soil. Methods: The field experiment was carried out in a randomized complete block design, which include four treatments, each with four replications. The plot size was 83.3 m2 (19.6 m in length, 4.25 m in width). Treatments were flooding irrigation combined with rice straw covering (FI-RS), flooding irrigation combined with Eleocharis dulcis covering (FI-ED, control), spray irrigation combined with rice straw covering (SI-RS) and spray irrigation combined with Eleocharis dulcis covering (SI-ED). Result: Experimental results showed that Allium chinense planted on the treatment of SI increased clump height (47.2 cm) and weight of bulb (4.38 g), gave the highest yield of 40.9 t ha-1 and increased up to 25.9% in comparison to planted in conventional method (control). The spray irrigation method was more suitable than the flooding irrigation method for growing Allium chinense. Vitamin C content in bulbs was not changed under different water irrigation methods combined with mulching materials. [ABSTRACT FROM AUTHOR]

Background. The characteristics of acid soil, often low pH and high toxicity, affect the growth and yield of plants. Aims. This study evaluates the effects of supplemented lime and microbial organic fertilizer on glutinous corn (Zea mays) and watermelon (Citrullus lanatus) yield, yield components, and economic efficiency on acid-sulfate soils. Materials and Methods. Two experiments were carried out in Phung Hiep District, Hau Giang Province, as a typical acid-sulfate soil area. The randomized complete block with four treatments and three replicates was designed for the experiment, in which supplemented fertilizers were 800 kg of lime/ha; 2,000 kg of microbial organic fertilizer/ha; and 800 kg of lime in combination with 2,000 kg of microbial organic fertilizer/ha, and treatment as farmer dose (FFT), without lime and microbial organic fertilizer. Results. As a result, using lime combined with microbial organic fertilizer increased the yield compared to using only lime or microbial organic fertilizer. Besides, the incomes increased to 12.0% and 13.8%, respectively, compared to farmer recommendations. Conclusion. To improve the yield of glutinous corn or watermelon and income on acid-sulfate soils, lime should be applied at 800 kg combined with 2,000 kg of microbial organic fertilizer/ha.

The aim of this study was to determine the proper combination of nitrogen (N) fertilizer level and nitrogen fixing endophytic bacteria (NFEB) supplementation for the maximum grain yield of sesame cultivated in alluvial soil in dykes. The experiment followed a completely randomized block design with two factors. The first one was the levels of N fertilizer used, including 0, 50, 75, and 100% N of recommended fertilizer formula (RFF), and the other consisted of no bacteria applied, an individual strain of Enterobacter cloacae ASD-48 or E. cloacae ASD-21 applied, and their mixture, with 5 replicates. The results revealed that fertilizing with 100% N of RFF led to an enhancement of the plant height (16.8 cm), the chlorophyll a and b and their total content (6.45, 1.86, and 8.30 μg mL−1), the number of capsules per plant (7.22 capsules plant−1), the total N uptake (126.5 mg N pot−1), and the grain yield (9.08 g pot−1), in comparison to no N fertilizer applied. Supplementation of two NFRB strains enhanced the soilconcentrations of NH4+ and NO3−, the total N uptake, and the grain yield. The treatment fertilized with 75% N of RFF plus an individual NFEB strain or their bacterial mixture had equivalent total N uptake to that the treatment fertilized with 100% N of RFF had, 120.8–125.5 mg N pot−1 compared to 124.4 mg N pot−1. Regarding the sesame yield, with a reduction by 25–50% N of RFF plus ASD-48 and ASD-21, either individually or in mixture, it increased by 2.39–8.56%, compared to that in the treatment fertilized with 100% N of RFF.

This study aimed to evaluate the effects of purple non-sulfur bacteria (PNSB) biofertilizers on soil properties, nitrogen (N) and phosphorus (P) uptakes, growth, and grain yield of sesame cultivated on salt-affected soil. N2-fixing and P-solubilizing bacteria used as biofertilizers were PNSB Rhodopseudomonas palustris VNW64, VNS89, TLS06 and VNS02, and endophytic bacteria (EB) Enterobacter cloacae X4 and Burkholderia acidipaludis X5. The experiment was conducted in a completely randomized block design, with 9 treatments (i) 100% N and 100% P of recommended fertilizer formula (RFF), (ii) 75% N and 50% P, (iii) 50% N and 50% P, (iv) treatment ii plus PNSB biofertilizers, (v) treatment iii plus PNSB biofertilizers, (vi) treatment ii plus EB biofertilizers, (vii) treatment iii plus EB biofertilizers, (viii) PNSB biofertilizers only, and (ix) carriers only, a rice straw and hush ash mixture. Results revealed that application of PNSB biofertilizers significantly improved soil fertility, nutrient uptakes, and yield as compared to treatments that used chemical fertilizers with or without EB biofertilizers at the same amount of N and P fertilizers applied. The use of 75% N and 50% P of RFF plus PNSB biofertilizers enhanced soil pHH2O, NH4+, soluble P, and N, P uptakes in sesame as compared to 100% N and 100% P of RFF. PNSB biofertilizers not only reduced 50% N and 50% P of RFF, but also maintained yield as compared to the treatment using 100% N, P of RFF (6.06 and 6.09 g pot−1, respectively) and limited Na uptake in sesame and Na+ concentration in the soil. [ABSTRACT FROM AUTHOR]

This study was conducted to (i) establish the diagnosis and recommendation integrated system (DRIS) for the macronutrient and micronutrient status of pineapple at the preflowering stage and (ii) verify the reliability of the established norms for macronutrients. We collected 86 pineapple leaves at sites +1 and +3 from 86 fields of pineapples grown in acid sulfate soil (ASS) and analyzed their nutrient content. Findings revealed the establishment of 12 and 20 nutrient ratios for DRIS norms at pineapple leaf sites +1 and +3. Based on omission fertilization of N, P, K, Ca, and Mg at the first crop, the DRIS index of N, P, K, and Mg was inadequate in treatments lacking the corresponding nutrients, whereas the DRIS index in the treatment fully fertilized with N, P, K, Ca, and Mg was negative and lower at the +3 leaf position. In the second crop, the DRIS norms were highly reliable via the negative DRIS index when fertilizing without N, P, K, Ca, and Mg. By contrast, when fertilizing with N, P, K, Ca, and Mg, the DRIS index was positive or less negative. The DRIS norms established that position +3 is robust and suitable for evaluating the pineapple macronutrient status. [ABSTRACT FROM AUTHOR]

Background: The study was carried out to determine the duration of drought and salinity level on growth, green matter yield and nutrient content in cowpea bean plants. Methods: The experiment was arranged in a 2-factor factorial style, including (A) three drought levels: (i) 07 days of watering, (ii) 14 days of irrigation and (iii) 21 days of watering cessation; factor (B) three salinity levels including (i) saline irrigation 2‰, (ii) saline irrigation 4‰ and (iii) saline irrigation 6‰. Each treatment has five replicates. Result: Experimental results showed that stopping irrigation of cowpea bean plants for 14 and 21 days reduced height, SPAD index, stomatal opening, DM, CP and ash content, compared to stopping watering for seven days. It reduced the yield of green matter and the nitrogen content in the plant. Besides, increasing salinity irrigation concentration at four and 6‰ declined the height, SPAD index, stomatal opening, DM, EE and CP of cowpea bean. The green matter yield and nitrogen content in the plants also decreased when irrigated with salinity 6‰. [ABSTRACT FROM AUTHOR]

Addition of biochar or organic fertilizers to the soil is very beneficial for enhancing the soil's quality and promoting plant development. The objective of this study was to identify the effects of applying biochar and sugarcane bagasse fertilizer alone or in combination on the improvement in soil properties and the productivity of hybrid maize in two consecutive crops. Field experiments were carried out in completely randomized block design with four treatments and five replications on Autumn 2020 and Summer 2021 crops. Treatments were control without application of rice husk biochar or sugarcane bagasse, application of 10 ton/ha of biochar, application of 10 tons/ha of sugarcane bagasse and combined 5 tons/ha of biochar and 5 tons/ha of sugarcane bagasse. The results in two consecutive crops showed that application of biochar, sugarcane bagasse fertilizer alone or in combination improved pH, increased available N, P and percentage of carbon in soils as well as increased the microbial density. Rice husk biochar alone or in combination with sugarcane bagasse fe rtilizer improved yield of hybrid maize. The findings of the research indicated that biochar application with 5 -ton ha-1 combined with 5-ton ha-1 of sugarcane bagasse fertilizer increased plant biomass and seed yield of hybrid maize. [ABSTRACT FROM AUTHOR]

This study aimed to (i) select endophytic bacteria in maize root for its phosphorus solubilization ability and (ii) evaluate the efficacy of selected indigenous bacterial strains on soil fertility, phosphorus (P) uptake, growth, and maize yield. A total of 31 maize root samples were collected from An Phu District, An Giang Province, to isolate the bacteria. In addition, the pot experiment was conducted with nine treatments of (i) 100% P of the recommended fertilizer formula (RFF), (ii) 75% P of the RFF, (iii) 50% P of the RFF, (iv) 25% P of the RFF, (v) 75% P of the RFF plus a mixture of the 3 selected strains, (vi) 50% P of the RFF plus a mixture of the 3 selected strains, (vii) 25% P of the RFF plus a mixture of the 3 selected strains, (viii) 0% P of the RFF plus a mixture of the 3 selected strains, and (ix) 0% P of the RFF plus none of the 3 selected strains. The results identified 72 isolates from LGI medium. All isolates were screened in a broth medium at pH 5.0, but only 16 isolates obtained OD660 > 0.5. All 16 isolates were able to solubilize various insoluble P fractions. Of those, strain ASD-21 had the highest P solubilization ability for the insoluble Al-P compound. Strains ASD-08 and ASD-21 had the highest Fe-P concentration at 39.8-41.5 mg P L-1. Strains ASD-08 and ASD-21 had the highest Ca-P concentration (46.6-51.3 mg P L-1) for 48 h of incubation. They were identified as Enterobacter spp. Results also showed the application of a mixture of strains ASD-08, ASD-10, and ASD-21 increased soil fertility by increasing phosphorus content by 13.7 mg P kg-1 and replacing 25% of P fertilizer, but this mixture did not change maize yield. [ABSTRACT FROM AUTHOR]

A large quantity of ESTs is available from various cDNA libraries of oil palm. The information from oil palm EST databases has been utilized to identify several interesting sequences for molecular characterization. In this study, we report molecular characterization of clone 583 (Acc. No. EU795363) isolated from cell suspension culture of oil palm. This clone is predicted to encode a single major open reading frame for a polypeptide of 177 amino acids with a predicted molecular mass of 19.6 kDa. The predicted amino acid sequence does not contain any signal peptide and transmembrane region. Based on Kyte-Doolittle hydropathy profile, this protein is predicted to be a soluble protein. The predicted ORF of clone 583 was 59% identical to an amino acid sequence of an unknown protein from Oryza sativa (Acc. BAD25663). Southern analysis showed that this clone might be a member of a multigene family in the oil palm genome. Gene expression study by real time quantitative RT-PCR showed that transcripts of clone 583 might be present in low abundance. [ABSTRACT FROM AUTHOR]

In this study, we report the molecular characterization of clone Eg707 isolated from cell suspension culture of the oil palm. The deduced polypeptide of clone Eg707 is highly similar to an unknown protein from Arabidopsis thaliana. The presence of an Ald-Xan-dh-C2 superfamily domain in the deduced protein sequence suggested that Eg707 protein might be involved in abscisic acid biosynthesis. Eg707 might be present as a single copy gene in the oil palm genome. This gene is highly expressed in tissue cultured materials compared to vegetative and reproductive tissues, suggesting a role of this gene during oil palm somatic embryogenesis or at the early stages of embryo development. Expression analysis of Eg707 by RNA in situ hybridization showed that Eg707 transcripts were present throughout somatic embryo development starting from proembryo formation at the embryogenic callus stages till the maturing embryo stages. Since proembryo formation within the embryogenic callus is one of the first key factors in oil palm somatic embryo development, it is suggested that Eg707 could be used as a reliable molecular marker for detecting early stage of oil palm somatic embryogenesis.