Kesan Interaksi Mikoriza Vesikular-Arbuskular (Mva), Paras Berbeza Vermikas Dan Baja Kimia Terhadap Pertumbuhan 3 Varieti Cili (Capsicum Annum L.) Tempatan

Kajian ini dilakukan untuk mengkaji kesan penggunaan Mikoriza Vesikular-Arbuskular (MVA), vermikas dan baja kimia terhadap pertumbuhan fizikal, kandungan nutrien, kandungan klorofil, peratus jangkitan MVA dan komposisi mikroorganisma mikorhizosfera pokok cili varieti MC11, MC12 dan MP. This research studied the effects of utilizing Vasicular-Arbuscular Mycorrhiza (VAM), different levels of vermicast and chemical fertilizer on the physical growth, nutrient status, chlorophyll content, percentages of VAM infection and mycorhizosphere microorganism population on three different varieties of chilly, MC11, MC12 and MP

Growth development and natural infection incidence of tobacco mosaic virus (TMV) on silicon-treated chilli (Capsicum annuum L.) cultivated in commercial soil

Chilli (Capsicum annuum L.) is one of the most important cultivated crops in Malaysia. It is largely cultivated for its fruits. The application of the chemical fertilizer solely is able to supply the desire nutrient for chilli plant but did not helping in resistant of pathogen attack. Therefore, this study attempts to determine the potential of silicon application on plant growth and disease resistant on treated plants. Chilli seedling were transplanted into individual polybag containing commercial soil and supplied with silicon at 0.5ml/L and 1.5ml/L concentrations for the period of 11 weeks. Control plants were supplied with water instead of silicon nutrient. Assessment was conducted from week 3 to 11 after transplanting. Result showed that the plant growth of chilli treated with both Si nutrient concentrations measured by plant height, leaf number, leaf diameter and stem diameter were significantly better than control plants. Besides, the natural occurrence of Tobacco Mosaic Virus (TMV) disease incidence observed on treated chilli were 26.7–44.4% reduced compared to control plants. This study provides the knowledge on the benefit of Silicon application on the cultivated chilli and could possibly help the farmers to produce higher and better quality of yield in the future

Composition and identification of pollen collected by stingless bee (Heterotrigona itama) in forested and coastal area of Terengganu, Malaysia

The aim of this study was to determine the composition and identify the pollen foraged by Heterotrigona itama in coastal and forested area over a period of nine months. The sampling has been conducted started from June 2016 until February 2017. Pollen composition obtained from the pollen basket of H. itama in coastal area and forested area of Terengganu was observed and recorded using optical microscope. Up until February, H. itama in coastal area had collected 14 different type of pollen, however only 10 types of pollen have been successfully identified. The identified pollen were Antigonan leptopus, Amaranthus tricolor, Hibiscus rosa-sinensis, Cucumis melo, Ixora coccinea, Tridax procumbens, Biden pilosa, Turnera subulata, Ixora javanica and Portula grandiflora which was the dominant pollen that has the highest percentage. Meanwhile H. itama in forested area has collected 15 different type of pollen with only 7 types of pollen have been successfully identified. The identified pollen were dominated by Asystasia gangetica followed by Biden pilosa, Antigonan leptopus, Reullia brittonia, Amaranthus tricolor, Hibiscus sabdariffa and Portulaca grandiflora. This observation could be useful for plants and H. itama conservation purposes and also in planning a suitable beescape for Meliponiculture in Malaysia

Enhanced growth of chili (Capsicum annuum L.) by silicon nutrient application in fertigation system

Silicon (Si) is one of the most abundant elements naturally available in the soil. This element performs an essential function in improving plant growth. This present study was carried out to evaluate the impact of Si nutrient application on the growth performance of chili (Capsicum annuum L.). Chili plant grown using a fertigation system was subjected to manual application of a silicon nutrient solution in varying concentrations (0 ppm, 108 ppm, 180 ppm, & 360 ppm) via root application. Each treatment was replicated five times, with five plants in each replicate, and all plants were grown in a shade house. The growth performance parameters measured were the number of leaves, stem diameter, plant height, plant biomass (dry weight), and Si accumulation in the stem, leave, and chili fruit. Results showed that Si nutrient application significantly affected the growth performances of chili plants. Application of T3 (360 ppm Si nutrient) was able to produce the highest stem diameter (8.92 mm), fresh weight (129.63 g), dry weight (67.23 g), as well as Si accumulation in stem (54 ppm), and chili fruit (24 ppm). On the other hand, applications with T2 (180 ppm Si nutrient) also demonstrated the highest plant height (20.98 cm), number of leave (27), and Si accumulation in leave (87 ppm). In conclusion, the application of silicon nutrients has the potential to enhance plant growth in numerous crops, making it a beneficial supplement to traditional agricultural practices

A new set of international Leptosphaeria maculans isolates as a resource for elucidation of the basis and evolution of blackleg disease on Brassica napus

© 2023 The Authors. Plant Pathology published by John Wiley & Sons Ltd on behalf of British Society for Plant Pathology. This is an open access article under the terms of the Creative Commons Attribution-Non Commercial-No Derivs License. https://creativecommons.org/licenses/by-nc-nd/4.0/A collection of isolates of the fungi Leptosphaeria maculans and L. biglobosa, which cause blackleg disease on Brassica napus (canola/oilseed rape) and other Brassicaceae species, was assembled to represent the global diversity of these pathogens and a resource for international research. The collection consists of 226 isolates (205 L. maculans and 21 L. biglobosa) from 11 countries. The genomes of all 205 L. maculans isolates were sequenced, and the distribution and identity of avirulence gene alleles were determined based on genotypic information and phenotypic reactions on B. napus lines that hosted specific resistance genes. Whilst the frequencies of some avirulence alleles were consistent across each of the regions, others differed dramatically, potentially reflecting the canola/oilseed rape cultivars grown in those countries. Analyses of the single-nucleotide polymorphism (SNP) diversity within these L. maculans isolates revealed geographical separation of the populations. This "open access" resource provides a standardized set of isolates that can be used to define the basis for how these fungal pathogens cause disease, and as a tool for discovery of new resistance traits in Brassica species.Peer reviewe

Leptosphaeria diseases of oilseed rape and swede: identification and epidemiology

Leptosphaeria maculans and L. biglobosa cause stem canker and dry rot disease on brassica crops. Although the disease has been reported to be present in New Zealand brassica cropping areas a comprehensive assessment of the causal agent and epidemiology has not been carried out. The aim of this study was to determine the causal agent(s) and to investigate the epidemiology under New Zealand conditions. Sampling of the disease tissue characteristic to stem canker/dry rot collected from different regions revealed that both Leptosphaeria maculans and L. biglobosa are present. Leptosphaeria maculans was the predominant species accounting for 97% (n=127) of the colonies recovered with the remaining 3% (n=4) identified as L. biglobosa. Initial species identification based on colony morphology was confirmed using molecular methods (species-specific PCR and sequencing). Leptosphaeria maculans was recovered from both symptomatic oilseed rape (OSR) and swede plants. Determination of the mating type ratio from 39 representative isolates of L. maculans showed that the population deviated from the expected 1:1 mating type ratio, being 5:1 ratio (MAT1-1:MAT1-2), with differences between regions. The previously sequenced avirulence alleles Avr1, Avr6, and Avr4-7 were present in the L. maculans with Avr6 being the most common and amplified from all 39 isolates. The most common allele structure was a single Avr6 (n=20), followed by multiple avirulence alleles Avr1, 6 (n=3), Avr1, Avr6, 4-7 (n=12), and Avr4-7, 6 (n=4). Pathogenicity tests using conidial suspensions of different L. maculans isolates showed that this species is pathogenic on both OSR and swede, with no correlation between pathogenicity and crop origin observed. Leaf lesions which developed on the L. maculans inoculated seedlings were characteristic of the reported symptoms being pale grey lesions with abundant pycnidia. Leptosphaeria maculans progressed systemically from the leaf lesions into the petiole and the adjoining stem to cause stem lesions. Stem lesions were first observed 42 day-post inoculation (dpi) on OSR and swede in the greenhouse experiments. The systemic progression was verified by isolation of the pathogen from the symptomless petiole and stem of inoculated plants, and also from the observation of fungal hyphae in the same tissue under fluorescent microscopy. At 65 dpi, some of the inoculated OSR and swede plants were killed. Swede was more susceptible than OSR, regardless of the tolerance ranking of cultivars. Mating type did not influence disease development in either OSR or swede. Although L. biglobosa was also pathogenic on OSR and swede, developing characteristic leaf lesions, stem/tuber lesions did not develop on inoculated plants after 65 dpi. Stem cankers developed both from systemic infection following leaf inoculation and also from direct conidial inoculation of the stem at the six-leaf stage for both swede and OSR. Symptom expression resulting from direct infection was more severe on swede compared to OSR. Mature leaves of seven month old swede plants were not susceptible to either ascospore or conidial infection and dry rot symptoms did not develop on the bulbs indicating no systemic progression. Direct inoculation of mature swede bulbs with either ascospores or conidia resulted in the development of dry rot symptoms. Symptoms developed four weeks earlier with ascospore inoculation compared with conidia. Spore trapping conducted in 2012-2013 using a 7-day Burkard and Rotorod spore sampler trapped ascospores of L. maculans/L. biglobosa in the field. Ascospores of both species were confirmed by nested-PCR using species-specific primers of the DNA extracted from the melinex tape, and showed that ascospores from both species were released concurrently. In field experiments, the effects of different stubble management practices on disease development in OSR were studied in two years. In 2012, there was no significant difference (P=0.844) in the disease incidence between stubble treatments (in direct drill, slashing and disking plots) and was probably due to cross-contamination by ascospores between plots. In 2013, the disease incidence in the direct drill treatment (72.7%) was significantly higher than in the ploughing (39.3%) and disking treated plots (36.0%). Results showed that the development of stem canker in the field resulted from systemic progression, with the timing of leaf lesion development coinciding with the timing of ascospore release. Systemic progression was verified by isolation of L. maculans from the symptomless petiole and stem of the plants which developed leaf lesions. The effect of the combination of burial and treatment of the OSR stubble with 5% urea on the development of pseudothecia was studied. The results showed that burial stimulated stubble degradation, with urea having no significant effect (P=0.234) on stubble weight. The combination of urea and burial reduced pseudothecial development with no fruiting bodies recovered from the stubble after 17 weeks. Both bacterial and fungal diversity assessed using denaturing gradient gel electrophoresis (DGGE) differed across assessment times. The burial treatment affected the carbon utilisation profile, analysed using the MicroRespTM system, of the soil microbial community associated with the stubble at the April (8 weeks) assessment, but urea application had not effect. Overall findings from this study showed that both ascospores and conidia of L. maculans were able to cause stem canker/dry rot disease. The disease was initiated by ascospores in the field with the high risk period of ascospore release between May-August. The disease can be reduced by targeting and eliminating the overwintering inoculum and hence primary spore production. From this study, a combination of 5% urea application and burial of the stubble after harvest was indicated as a method to reduce inoculum carry over

Effect of different types and concentration of rooting hormones on Momordica cochinensis (Gac fruit) root vine cuttings

Momordica cochinchinensis (Gac fruit) grows as perennial climbers and dioecious plants, where it can be cultivated from seeds, root tubers, and root vine cuttings. Rooted vine cuttings are more reliable than seed propagation, which can be affected by dormancy and delay production. The application of auxin group of hormones such as Indole acetic acid (IAA), Indole-3- butyric acid (IBA), and Naphthaleneacetic acid (NAA) in certain concentrations shown good results in inducing root initiation faster and effective. However, experimental data and information on the plant growth hormone application on M. cochinchinensis vine cuttings propagation are not very extensive, especially in Malaysia. Thus, the objective of this study was to determine the effect of different concentrations of IAA, IBA, and NAA on M. cochinchinensis vine cutting propagation. The design of the experiment is a randomized complete block design in a factorial experiment, with five replications. The treatments comprised three types of plant growth hormone, IAA, IBA, and NAA with 0, 500, 1000, and 3000 ppm concentrations. Data recorded were surviving rate or percentage of rooting, root numbers per rooted cutting, means of root length, length of longest root, total root length per rooted cuttings, sprouting percentage, and sprouting length. The vine cutting treated with IBA and NAA 1000 ppm has shown a considerably positive effect in root formation and sprouting

Identification of Leptosphaeria species causing stem canker and dry rot disease of Brassica species in New Zealand

Leptosphaeria maculans and L. biglobosa are major pathogens of brassica crops, including canola (oilseed rape) and swede. Selection of canola cultivars with resistance genes to correspond with the avirulence genes of the local fungal population is an approach used overseas for controlling the disease. This study aimed to determine the main causal agent(s) in New Zealand, and, for a subset of 30 L. maculans isolates, the presence of 7 avirulence alleles (AvLm1, AvLm2, AvLm4, AvLm5, AvLm6, AvLm7, and AvLm11). The pathogenicity of these isolates on canola ‘Flash’ and swede ‘Highlander’ was also determined. Leptosphaeria maculans was the predominant species (n=127) recovered from leaf lesions, stem canker and dry rot tissue on canola, swede and turnip plants, with only 4 isolates identified as L. biglobosa recovered from stem cankers on canola, cauliflower and kale. All avirulence alleles were present in the New Zealand L. maculans population, with AvLm5 and AvLm6 amplified from all 30 isolates. The most common allele structure was avLm1-avLm2-avLm4-AvLm5-AvLm6- AvLm7-avLm11 (n=15, Avr refers to avirulence and avr refers to virulence allele) representing isolates recovered from canola, swede and turnip across New Zealand, followed by avLm1-avLm2-AvLm4- AvLm5-AvLm6-AvLm7-AvLm11 (n=7) only recovered from canola from Canterbury. L. maculans isolates were more pathogenic on swede ‘Highlander’ than canola ‘Flash’, forming more extensive stem cankers on swede after 65 days. There was no correlation between pathogenicity of the isolates and crop origin, or avirulence groupings observed. This study provides a base line evaluation of the avirulence allele frequencies in the New Zealand L. maculans population

Antifungal activity of extracts against Colletotrichum species in harvested chili

Chili is an important vegetable fruit but is commonly attacked by anthracnose disease during field or storage. A current practical method to control this disease is through synthetic fungicides. Although it shows the effective result, repetitive application of chemical fungicides may build up resistant pathogens, expose the risk to human health, and be regarded as not eco-friendly to the environment. This study aimed to evaluate the antifungal activity of several extracts and their potential to control Colletotrichum sp. in harvested chili. For this purpose, several plant extracts namely garlic, ginger, dragon fruit peel (DFP), and milk were used with the concentration ranged from 5 to 20%. All these extracts and milk were tested through in vitro antifungal assay and in vivo antifungal assay directly on the detached chili. The results show that garlic, ginger, and DFP were able to significantly inhibit the fungal pathogen of Colletotrichum sp. through in vitro study with p<0.05. Based on in vivo study, the only chili treated with 20% garlic extract, 20% ginger extract, and fungicide recorded a significantly lower percentage of disease severity (ds) as compared to the other extracts. Both 20% garlic and 20% ginger extracts showed good potential to inhibit the fungal pathogen. Therefore, the application of natural extracts should be focused and practically used as a control strategy in integrated pest management for plant disease, especially in chili production. This control measure is expected to reduce yield losses, operational cost while mitigating the environmental contamination due to overdose chemical residue

Urea in combination with burial reduces the production of pseudothecia on Leptosphaeria maculans infected stubble

Leptosphaeria maculans, the causal agent of black leg of canola survives between crops on infected stubble. Pseudothecia containing ascospores produced on diseased material provide the primary inoculum to infect subsequently planted canola crops. The effect of burial in combination with urea application on L. maculans pseudothecial production and maturation on diseased stubble was determined. In addition, the population diversity and carbon utilisation profile (CUP) of the soil microbial community associated with the stubble was assessed