Identification and characterization of <Emphasis Type="Italic">Colletotrichum</Emphasis> spp. associated with chili anthracnose in peninsular Malaysia

Anthracnose fruit rot caused by Colletotrichum spp. is a serious post-harvest disease of chili fruits (Capsicum spp.). One hundred-thirty isolates of Colletotrichum spp. were isolated from anthracnose of green and red cayenne pepper (Capsicum annuum) and bird’s eye chili (Capsicum frutescens). The isolates were morphologically identified as Colletotrichum acutatum sensu lato (62 isolates), Colletotrichum truncatum (54 isolates), and Colletotrichum gloeosporioides sensu lato (14 isolates). Molecular identification and phylogenetic analyses were based on internal transcribed spacer regions, β-tubulin, actin, and glyceraldehyde-3-phosphate dehydrogenase genes, and the isolates were re-identified as C. scovillei (58 isolates), C. truncatum (54 isolates), C. siamense (11 isolates), C. fioriniae (four isolates), and C. fructicola (3 isolates). Maximum likelihood trees using combined sequences showed that isolates of the same species grouped in the same main clade with the isolates used for comparison. Pathogenicity testing showed that the tested isolates from each species were pathogenic towards green and red Capsicum annuum and Capsicum frutescens upon treatment of wounded fruit, using both the mycelial plug and conidial suspension methods. Only five isolates of C. truncatum and seven isolates of C. scovillei were found to be pathogenic upon treatment of unwounded fruit. The occurrence of five Colletotrichum spp. (C. siamense, C. fructicola, C. scovillei, C. fioriniae, and C. truncatum) associated with chili anthracnose in Peninsular Malaysia indicates that correct species identification is important to formulate not only effective disease management, but also effective quarantine policy.     

Surfactants in the Sea Surface Microlayer,Underlying Water and Atmospheric Particles of Tropical Coastal Ecosystems

This study aims to determine the composition of surfactants in the sea surface microlayer (SML), underlying water (ULW) and atmospheric particles (AP). Surfactants were determined colorimetrically as methylene blue active substances (MBAS) and disulphine blue active substances (DBAS) for anionic and cationic surfactants, respectively. The concentration of dissolved inorganic nutrients (DIN) in ULW was determined so as to indicate the influence of ULW to the surfactants in SML. The results showed that the concentration of MBAS and DBAS in SML at both stations ranged between 0.05 and 0.31 μmol L^?1, and between 0.19 and 0.59 μmol L^?1, respectively. Surfactants in ULW influence the concentration of surfactants in SML (r?=?0.65, p?<?0.01, n?=?36). The station influenced by anthropogenic sources showed a higher concentration of surfactants in ULW, SML and AP. This finding suggests fine mode atmospheric particles (FMAP) are the main carrier for anionic surfactants as MBAS in the coastal ecosystem. Anionic surfactants as MBAS were found as better indicator of anthropogenic sources than cationic ones.     

Detecting mislabeling and identifying unique progeny in <Emphasis Type="Italic">Acacia</Emphasis> mapping population using SNP markers

Acacia hybrids offer a great potential for paper industry in Southeast Asia due to their fast growth and ability to grow on abandoned or marginal lands. Breeding Acacia hybrids with desirable traits can be achieved through marker assisted selection (MAS) breeding. To develop a MAS program requires development of linkage maps and QTL analysis. Two mapping populations were developed through interspecific hybridization for linkage mapping and QTL analysis. All seeds per pod were cultured initially to improve hybrid yield as quality and density of linkage mapping is affected by the size of the mapping population. Progenies from two mapping populations were field planted for phenotypic and genotypic evaluation at three locations in Malaysia, (1) Forest Research Institute Malaysia field station at Segamat, Johor, (2) Borneo Tree Seeds and Seedlings Supplies Sdn, Bhd. (BTS) field trial site at Bintulu, Sarawak, and (3) Asiaprima RCF field trial site at Lancang, Pahang. During field planting, mislabeling was reported at Segamat, Johor, and a similar problem was suspected for Bintulu, Sarawak. Early screening with two isozymes effectively selected hybrid progenies, and these hybrids were subsequently further confirmed by using species-specific SNPs. During field planting, clonal mislabeling was reported and later confirmed by using a small set of STMS markers. A large set of SNPs were also used to screen all ramets in both populations. A total of 65.36% mislabeled ramets were encountered in the wood density population and 60.34% in the fibre length mapping population. No interpopulation pollen contamination was detected because all ramets found their match within the same population in question. However, mislabeling was detected among ramets of the same population. Mislabeled individuals were identified and grouped as they originated from 93 pods for wood density and 53 pods for fibre length mapping populations. On average 2 meiotically unique seeds per pod (179 seeds/93 pods) for wood density and 3 meiotically unique seeds per pod (174 seeds/53 pods) for fibre length mapping population were found. A single step statistical method was used to evaluate the most informative set of SNPs that could subsequently be used for routine checks for mislabeling in multi-location field trials and for labelling superior clones to protect breeder’s rights. A preliminary set of SNPs with a high degree of informativeness was selected for the mislabeling analysis in conjunction with an assignment test. Two subsets were successfully identified, i.e., 51 SNPs for wood density and 64 SNPs for fibre length mapping populations to identify all mislabeled ramets which had been previously identified. Mislabeling seems to be a common problem due to the complexity involved in the production of mapping populations. Therefore, checking for mislabeling is imperative for breeding activities and for analyses such as linkage mapping in which a correlation between genotypic and phenotypic data is determined.     

Distribution patterns of tree,understorey, and detritus biomass in coniferous and broad-leaved forests of Western Himalaya,India

Forest biomass pools are the major reservoirs of atmospheric carbon in both coniferous and broad-leaved forest ecosystems and thus play an important role in regulating the regional and global carbon cycle. In this study, we measured the biomass of trees, understorey, and detritus in temperate (coniferous and broad-leaved) forests of Kashmir Himalaya. Total ecosystem dry biomass averaged 234.2 t/ha (ranging from 99.5 to 305.2 t/ha) across all the forest stands, of which 223 t/ha (91.9–283.2 t/ha) were stored in above- and below-ground biomass of trees, 1.3 t/ha (0.18–3.3 t/ha) in understorey vegetation (shrubs and herbaceous), and 9.9 t/ha (4.8–20.9 t/ha) in detritus (including standing and fallen dead trees, and forest floor litter). Among all the forests, the highest tree, understorey, and detritus biomass were observed in mid-altitude Abies pindrow and Pinus wallichiana coniferous forests, whereas the lowest were observed in high-altitude Betula utilis broad-leaved forests. Basal area has showed significant positive relationship with biomass (R² = 0.84–0.97, P < 0.001) and density (R² = 0.49–0.87). The present study will improve our understanding of distribution of biomass (trees, understorey, and detritus) in coniferous and broad-leaved forests and can be used in forest management activities to enhance C sequestration.     

Socio-economic factors influencing marketing of non-timber forest products in tropical lowland rainforests of south-western Nigeria§

A number of factors persist to constrain the non-timber forest products (NTFPs) market and, by extension, its potential to contribute meaningfully to livelihood development and poverty reduction objectives. To better utilise the potential of NTFPs, it is important to have a better understanding of the key factors governing the success and failure of NTFPs trade. This paper reports on the market constraints and socio-economic factors that influence trade in five top-priority NTFPs within the tropical lowland rainforests of south-west Nigeria. The NTFPs investigated were bush mango (Irvingia gabonensis), African walnut (Plukenetia conophora), chew-stick (Massularia acuminata), fever bark (Annickia chlorantha) and bush pepper (Piper guineense). Field data were collected in 10 villages located within and around Omo and Shasha forest reserves using a household questionnaire survey. The results showed that seasonality, poor transport, lack of storage facilities and market information were the four main constraints influencing marketing and trade in the NTFPs. In addition, the level of education, gender (sex), household income, ethnicity, distance to the market and access to roads significantly influenced market knowledge and information among households involved in the trade of NTFPs. There is need to improve on the limited source of NTFPs information, enhance skills for product transformation, build innovative storage facilities, and develop the process of domestication and integration in traditional land-use systems.     

Variation in zinc efficiency among and within Aegilops species

Fifteen accessions of Aegilops tauschii (DD), 10 of Ae. speltoides (SS) and 8 of the tetraploid Aegilops species sharing the U genome were used to study the influence of varied zinc (Zn) supply on development of Zn-deficiency symptoms, and on shoot dry weight and Zn concentration. Plants were grown in a Zn-deficient calcareous soil under greenhouse conditions with (+Zn = 5 mg kg^—1 soil) and without (—Zn) Zn supply. Four accessions of wild tetraploid wheat, Triticum turgidum var. dicoccoides (BBAA), a group known for its high sensitivity to Zn-deficiency, were used in the experiments for comparison. As expected, the accessions of wild T. turgidum var. dicoccoides showed the highest sensitivity to Zn deficiency, and had more severe leaf symptoms of Zn deficiency (whitish-brown necrotic patches). Among the Aegilops species, leaf symptoms of Zn deficiency were, in general, more distinct in Ae. tauschii (DD) and least in Ae. speltoides (SS). Zinc efficiency, expressed as the percentage of shoot dry weight produced under conditions of Zn deficiency compared to Zn supply, averaged, 15% for T. turgidum, 32% for Ae. tauschii, 52% for Ae. speltoides and 61% for the tetraploid Aegilops species carrying the U genome. Differences in Zn efficiency among and within Aegilops species and T. turgidum were significantly correlated with the Zn amount per shoot, but not with the Zn amount per unit dry weight of shoots. The results show that Aegilops species can be exploited as an important genetic source for Zn efficiency genes, particularly Ae. speltoides var. ligustica (SS) and Ae. triuncialis (UUCC). Transfer of these genes to cultivated modern wheat may bring about a greater variation in Zn efficiency in wheat, and facilitate production of Zn-efficient modern wheat cultivars for Zn-deficient soil conditions.     

Dynamics of glucose in the haemolymph of female giant freshwater prawn,Macrobrachium rosenbergii,influences reproductive and non‐reproductive moulting cycles

Glucose, when measured in haemolymph, has been found to reflect a useful predictor of energetic investment. This study evaluated the pattern of glucose in the haemolymph, with an attempt to gain a better insight into the role of glucose as nutritional source of ovarian development and energy reserves during reproductive and non‐reproductive moulting cycles. The haemolymph of female giant freshwater prawn, Macrobrachium rosenbergii, was obtained at eight different moulting stages, and levels of glucose were determined using an enzymatic colorimetric glucose‐oxidase method in parallel with a histological examination of ovarian development. Glucose levels were relatively low (0.15 ± 0.02 mg mL^?1) at D₀ stage, an abrupt increase (0.52 ± 0.13 mg mL^?1) during premoult D₁ stage and declined (0.32 ± 0.10 and 0.31 ± 0.09 mg mL^?1) during premoult D₂ and D₃ stages, respectively; thereafter, a slight increase (0.43 ± 0.09 mg mL^?1) occurred at post‐moult A stage. The progression of ovarian growth, marked by an increasing gonadosomatic index (GSI) pattern during the reproductive moulting cycle (C₀–D₃ stages), was directly proportionate to fluctuations in glucose levels. GSI was significantly positively correlated with glucose (R = 0.40; P < 0.05). In contrast, glucose was notably higher at post‐moult A and premoult D₂ stages during non‐reproductive moulting cycle, the period during which glucose is crucial for exoskeletal chitin synthesis. At this particular stage, a negative correlation between body weight and glucose (R = ?0.36; P < 0.05) was observed. The dynamics of glucose in the haemolymph of female M. rosenbergii correlated with ovarian growth, which signify that glucose as nutritional source for vitellogenesis, and affects the body weight of this species.     

Allelic segregation of sex‐linked microsatellite markers in Nile tilapia (Oreochromis niloticus) and validation of inheritance in YY population

Stocking of all‐male fingerling produced by direct administration of male hormone 17‐α‐methyltestosterone is the most preferred method for present‐day aquaculture of the Nile tilapia Oreochromis niloticus. However, due to the growing concern of negative impact of steroid hormone in food fish, production of ‘genetically male’ tilapia, which depends on the concrete and thorough understanding of sex determination, has long been a scientific curiosity. The objective of the present study was to identify reliable sex‐linked markers and to evaluate the applicability of those markers in terms of monosex production approach. ‘XY’ neofemales were produced by using synthetic oestrogen and identified through selective breeding and progeny testing. Three females with progeny not deviating from 3:1 sex ratio (male:female) were designated as ‘XY’ neofemales and were used subsequently to produce putative YY progeny. Among the fifteen microsatellite markers tested, marker ARO172 was most informative in differentiating male and female genotypes. Twenty‐seven F₂ fish from three families were identified as putative YY males based on marker genotyping, and four of them were crossed to produce F₃ to validate marker association by progeny testing. The YY males produced 86%–100% male progeny indicating ARO172 a unique sex‐linked marker applicable in marker‐assisted selection.     

Antimicrobial Activity of Selected Essential Oils on Pseudomonas Species Associated with Spoilage of Fish with Emphasis on Cinnamon Essential Oil

ABSTRACT

Eight plant essential oils (cardamom, cinnamon, clove, eucalyptus, lemongrass, lime, nutmeg and rosemary) were evaluated for their antimicrobial activity against three Pseudomonas species associated with microbial spoilage of refrigerated tilapia. In vitro test of the essential oils, using disc-diffusion method, showed various degrees of antimicrobial activity against the Pseudomonas species. Cinnamon essential oil (CEO) had the highest antimicrobial activity, followed by clove essential oil. The remaining essential oils showed consistently weak activity. The antimicrobial efficiency of CEO against the Pseudomonas species was confirmed by potential minimum inhibitory concentration and minimum bactericidal concentration values, ranging between 0.125 and 0.375 µL/mL and 0.250–0.500 µL/mL, respectively. The anti-Pseudomonas activity of CEO was also tested in fish extract model at refrigeration temperature. The essential oil reduced the Pseudomonas viable count in fish extract but to a lesser extent than when it was applied at the same concentrations in culture medium. The chemical composition of CEO showed that the oil contained 79.1% cinnamaldehyde, which was suggested to be responsible for its antimicrobial activity. These results revealed the potential of CEO as a promising natural antimicrobial agent that could efficiently contribute to the control of spoilage bacteria and retard microbial spoilage of fresh fish.