Potential for enhancement of root growth and nodulation of soybean co-inoculated with Azospirillum and Bradyrhizobium in laboratory systems

The potential enhancement of root growth and nodulation in vegetable soybean (AGS190) was studied with application of Azospirillum brasilense (Sp7) and A. lipoferum (CCM3863) co-inoculated with two Bradyrhizobium japonicum strains (TAL102 and UPMR48). Significant root growth stimulation and nodulation were observed in Azospirillum as well as during its co-inoculation with Bradyrhizobium. Nodule formation is linked with the initiation of new roots; nodules were almost absent even in Bradyrhizobium inoculated plant due to the absence of new roots development in clipped rooted seedlings. Total root length, root number, specific root length, root dry matter, root hair development and shoot dry matter were significantly increased by Azospirillum alone and its co-inoculum. Co-inoculated plants significantly influenced the number of nodules and its fresh weight. A. brasilense seemed to perform better in root growth and nodule development compared to A. lipoferum

Effects of nitrification inhibitor with organic manure and urea on protein and mineral contents in grain of Oryza sativa cv. MR219 cultivated in acid sulphate soil

Several approaches to improve grain nutritive values involve in increasing seed accumulation of protein and micronutrients in rice. Therefore, a study was conducted to select a suitable combination of dicyandiamide (DCD) with organic manure (OM) and urea to improve protein and mineral content in rice grain of MR219. The protein (9.07-12.50%) and Ca, Mg, Zn, Cu, Fe and Mn concentrations increased from 1.92 to 21.05, 3.56 to 18.25, 2.25 to 20.22, 9.14 to 25.66, 3.34 to 27.20 and 5.17 to 23.86%, respectively due to the application of DCD with urea and OM. Moreover, the highest content of protein in grain was obtained for the application of DCD with urea and oil palm compost (OPC). Iron and Mn contents were also highest for DCD with urea and OPC, but Ca, Mg, Zn and Cu contents were highest for DCD with urea and poultry dung (PD) and kept similarity with DCD with urea and OPC

Changes of physical and chemical characteristics during microbial composting of rice straw at various pH levels

The physical and chemical parameters were monitored for seven weeks during Trichoderma/Aspergillus inoculated rice straw composting at various pH levels. Three treatments (A, B, and C) were inoculated with lignocellulolytic microbial consortium (Aspergillus niger, F44 and Trichoderma viride, F26) and three were un-inoculated (D, E, and F). pH of the starting materials was amended to 5.75 (A and D), 6.75 (B and E), and 7.75 (C and F) with either acetic acid or sodium hydroxide. Three typical phases of temperature were observed both in inoculated and un-inoculated treatments during composting: mesophilic phase, thermophilic phase, and followed by cooling and maturation phase. The bioconversion were maximum in Trichoderma/Aspergillus inoculated treatments within 14–21 days as indicated by the profiles of electrical conductivity, bulk density, total carbon and nitrogen, and germination index. After day 21, the germination index of Trichoderma/Aspergillus inoculated treatment (B) without any pH amendment was increased to 74.5 indicating the maturity of compost and suitability for field application

Effectiveness of different phytohormones on grain filling and yield of rice (Oryza sativa L.) under drought stress

Drought is a major limiting factor affecting rice yield and productivity all over the world, including Malaysia. To induce drought resistance, there is an increasing interest in using different phytohormones for field crop production considering its efficiency, feasibility, cost and labour-effectiveness. A greenhouse experiment was conducted to evaluate effectiveness of five different phytohormone treatments as Vita-Grow Plus (commercial phytohormones product), epibrassinolide, spermine, pyroligneous acid and without any of those or control including three times of application (single spray at 35 days after sowing, DAS; double spray at 35 and 55 DAS and triple spray at 35, 55 and 85 DAS) on growth and yield parameters of rice (Oryza sativa L.). Drought stress was exposed by regulating irrigation schedule. It was observed that all applied growth regulators have more or less progressive effect on rice growth and productivity. Both epibrassinolide and spermine application caused highest grain filling and spermine application highest (66.4%) grain yield. Considering yield components and grain yield, double spray of phytohormones was best. Therefore, two times spray (35 and 55 DAS) of spermine could be suggested for rice cultivation in the drought affected areas of Malaysia or other areas in the tropical region with similar ecologies

First report of tomato anthracnose caused by Colletotrichum boninense in Malaysia

In May, 2013, severe anthracnose symptoms were observed on the leaves of tomato plants grown in the Cameron Highlands (Pahang, Malaysia). The disease incidence reached 40% on mature leaves. Typical symptoms included circular, immersed lesions with orange spore masses in a dark centre. When grown on potato dextrose agar at 25°C with a 12 h photoperiod, colonies of a fungus isolated from symptomatic leaves were cream-to-orange coloured. These morphological characteristics are consistent with the description of Colletotrichum boninense (Moriwaki et al., 2003). Conidia measured 12.5-15.5×4.6-5.1 μm, were generally cylindrical, had obtuse ends and a hilum-like low protrusion at the base. Conidial length/width ratio was 2.8 to 3.0. The internal transcribed spacer RNA region was sequenced (GenBank accession No. KM039057.1) and proved 99% similar to that of C. boninense accession no. KJ619456.1. Tomato plants were inoculated with 40-μl droplets of a conidial suspension (105 conidia/ml) onto the surface of wounded and non-wounded leaves, using a sterilized hypodermic needle and were then kept in a moist chamber for seven days at 25°C with a 12-h photoperiod. Sterile distilled water was used for inoculating the leaves of control plants. Leaves inoculated with the pathogen showed symptoms similar to those observed in the field within 3-6 days, while no symptoms were present on controls. To the best of our knowledge, this is the first report of C. boninense infecting tomato in Malaysia

Efficacy evaluation of empty palm oil fruit bunch compost in improving soil characteristics, plant growth and disease suppression of tomato plants under tropical acid soils

Aim: Tomato is one of the most important crops worldwide as it is the second most important vegetable in the world after potato. A study was conducted to investigate the efficacy of empty fruit bunch (EFB) compost in improving soil characteristics, plant growth and disease suppression of tomato plants under tropical acid soil. Methodology: Twelve tomato seedling cv MT-11 were transplanted on each planting bed. The growth of tomato plant was assessed based on plant height, leaf area, dry matter weight and incidence of bacterial wilt disease. Soil sampling was done at 45 and 60 day after transplanting (DAT) for physio-chemical and microbial properties. Results: Applying EFB compost increased plant height, leaf area, dry matter accumulation, and suppressed development of bacterial wilt disease compared to using chicken manure. A higher disease reduction (16.7 %) occurred with 15 mg ha⁻¹ EFB compost, followed by 22.5 mg ha⁻¹ EFB compost (14.3 %), and 7.5 mg ha⁻¹ EFB compost (8.33 %). Interpretation: Organic amendment in tomato cultivation affects soil properties, plant development and disease suppression. Application of EFB compost at 15 mg ha⁻¹ appeared as the best treatment soil amendment in tomato cultivation under tropical acidicsoil condition

Impact of nitrification inhibitor with organic manure and urea on nitrogen use efficiency and yield performance of MR219 rice in acid sulphate soil

A glasshouse experiment was designed to study the effects of nitrification inhibitor (Dicyandiamide; DCD) with organic manure and urea on nitrogen use efficiency (NUE), growth performance and yield of MR219 rice. DCD along with N source increased NUE and apparent N recovery over that of sole application of urea. Application of DCD along with urea and oil palm compost (OPC) resulted in the highest NUE (25.94 kg/ha) and fertilizer N recovery by rice (61.75%) together with the highest increase of panicles/hill (17.43%) and filled grains/panicle (9.42%) over urea alone. The highest grain (21.95%) and straw (13.86%) yield increase over control was achieved from DCD with urea and OPC reflecting as the most potential combination to improve NUE and rice yield in acid sulphate soil

Isolation, identification and characterization of endophytic bacteria antagonistic to Phytophthora palmivora causing black pod of cocoa in Malaysia

Black pod rot is the most significant factor limiting production of cocoa (Theobroma cacao) in Malaysia with average annual losses of above 30%. This work was carried out to isolate, characterize and screen bacterial endophytes from cocoa plants for their biological control activities. Their mechanisms of action as well as abilities to reduce black pod rot disease were also investigated. In total, 103 endophytic bacterial isolates were obtained from healthy cocoa tissues (leaves, branches and fruits) from seven states of Malaysia in 2016 and screened for their antagonism against P. palmivora in vitro. The best two isolates AS1 and AS2 with more than 80% inhibition of radial growth (PIRG) were selected for subsequent experiments. Sequence analysis of the 16S rRNA region indicated that these two isolates belonged to Pseudomonas aeruginosa (AS1) and Chryseobacterium proteolyticum (AS2). Bioactive volatile compounds were identified using gas chromatography-mass spectrometry (GCMS). Major compounds present in P. aeruginosa extract were identified as Eicosane (9.11%), Hexatriacontane (6.87%), Tetratetracontane (5.17%), trans-2-Decenoic acid (17.04%) and 1-Phenanthrenecarboxylic acid, 1,2,3,4,4a,9,10,10a-octahydro-1,4a-dimethyl-7-(1-methylethyl) (3.60%). In C. proteolyticum extract, major compounds were identified as Eicosane (11.29%), Tetratetracontane (10.82%), Heneicosane (10.78%), Hexatriacontane (9.04%) and Phenol, 2,4-bis(1,1-dimethylethyl) (5.92%). Effectiveness of P. aeruginosa and C. proteolyticum in reducing black pod lesion was confirmed on detached cocoa pods with 100% inhibition for both isolates. These results indicated that these two bacterial isolates have potential to be used as bio-control agents against P. palmivora

Mineral phosphate solubilization of rhizobia and endophytic nodule bacteria of legumes.

Nitrogen and phosphorous are two of the main elements required for plant growth. Beneficial microorganisms can supply nitrogen through biological nitrogen fixation and increase P uptake by P solubilization of mineral phosphates through the production of organic acids. Rhizobium is a well established biological nitrogen fixer but other potential characteristics that promote overall plant growth have been largely ignored. A study was carried on rhizobia and root nodule endophytes from legumes to determine their phosphate solubilizing ability using solid and broth media containing mineral phosphates. A total of 160 rhizobia and root nodule endophytes were tested. Only 42 isolates (26.25%) showed phosphate solubilization activity using solid agar media and from these, a further 14 isolates were studied based on growth in various liquid mineral phosphate media. Isolate GM 119, a root nodule endophyte from Glycine max, showed the best result for phosphate solubilization on media containing Ca,(P04)2