Effect of biocontrol agents and biofertilizers on root rot,yield, harvest index and nutrient uptake of cassava (Manihot esculanta Crantz)

Cassava is an important subsidiary food and industrial raw material in the tropics. Root rot disease, caused by Phytophthora palmivora, poses a serious threat to cassava cultivation in Tamil Nadu, India. Field experiments (2008–09) were conducted to study the effect of biocontrol agents (Trichoderma spp. and Pseudomonas fluorescens) and biofertilizers (Azospirillum, vesicular–arbuscular mycorrhizal fungi and phosphorus-solubilizing bacteria) on root rot, yield, harvest index and nutrient uptake of cassava at two NPK rates. The design of the experiment was a split plot with two NPK rates, recommended and 50% recommended rate, as the main plot treatments and five biocontrol agents and biofertilizers as subplot treatments. The results clearly indicated that use of a bioinoculants consortium significantly reduced root rot infection/disease incidence over uninoculated controls. Azospirillum significantly improved the yield of cassava at 50% of the recommended rate of NPK. NPK rates had no significant impact on harvest index of cassava and Trichoderma and vesicular–arbuscular mycorrhizal fungi resulted in a higher harvest index even at 50% of the recommended NPK rate. Nitrogen, phosphorus and potassium uptake was significantly improved when treated with biofertilizers and/or a consortium.     

Induction of resistance against downy mildew pathogen in pearl millet by a synthetic jasmonate analogon

The synthetic 1-oxo-indanoyl-l-isoleucine methyl ester (Ind-Ile-Me) represents a highly active mimic of octadecanoic phytohormones, which are involved in plant defenses against pathogens and pests. Seed treatments and foliar spray with Ind-Ile-Me were tested for induced resistance against downy mildew disease caused by the phytopathogenic oomycete Sclerospora graminicola in pearl millet (Pennisetum glaucum) under greenhouse and field conditions. Under greenhouse conditions, a 50% protection level was achieved after seed treatment. Seed treatment in combination with foliar spray resulted in 60% protection. The induction of resistance was correlated with the enhanced activities of defense-related proteins such as phenylalanine-ammonia-lyase, peroxidase, and enhanced level of hydroxyproline-rich glycoproteins. Under field conditions, a maximum protection of 62% was recorded upon seed treatment along with foliar spray. Hence, it infers that Ind-Ile-Me can be used as a valuable protection compound at least in downy mildew disease management.     

Identification and pathogenicity study of emerging fish pathogens Acinetobacter junii and Acinetobacter pittii recovered from a disease outbreak in Labeo catla (Hamilton, 1822) and Hypophthalmichthys molitrix (Valenciennes, 1844) of freshwater wetland in West Bengal,India

The disease outbreaks in aquaculture system of wetlands are the major cause of fish mortality. Among various bacterial septicaemic diseases, fish mortality caused by Acinetobacter spp. is recently reported in different fish species. Fish disease outbreak was investigated in a wetland of West Bengal, India to identify the aetiological factors involved. The moribund fish were examined and subjected to bacterial isolation. Two bacterial causative agents were identified as Acinetobacter junii and Acinetobacter pittii by biochemical characterization and 16S rRNA gene amplification. Both the isolates were oxidase‐negative, nitrate‐negative, catalase‐positive and indole‐negative. The molecular identification using 16S rRNA gene sequencing and phylogenetic tree analysis further confirmed the two Acinetobacter spp. with 97%–99% similarity. The antibiotic resistance patterns of these two bacteria revealed that both of them were resistant to β‐lactam, cefalexin, cephalothin, amoxyclav, cefuroxime, cefadroxil, clindamycin, vancomycin and penicillin. In addition, A. pittii was also resistant to other antibiotics of cephams group such as ceftazidime and cefotaxime. In the challenge experiment, both A. junii and A. pittii were found to be pathogenic with LD₅₀ of 1.24 × 10⁵ and 1.88 × 10⁷ cfu/fish respectively. Histopathological examination of gill, liver and kidney revealed prominent changes supporting bacterial septicaemia. The investigation reports for the first time on concurrent infection by A. junii and multidrug‐resistant (MDR)‐A. pittii as emerging fish pathogens to cause severe mortality in Labeo catla and Hypophthalmichthys molitrix in a freshwater wetland.     

Prediction of soil depth using environmental variables in an anthropogenic landscape, a case study in the Western Ghats of Kerala, India

Soil (regolith) depth is a crucial input for modeling earth surface phenomena. However, most studies ignore its spatial variability. Techniques that map the spatial variability of soil depth are of three types: (1) physically-based; (2) empirico-statistical from environmental correlates; and (3) interpolation from point observations. In an anthropogenic landscape, soil depth does not depend primarily on natural processes, making it difficult to apply a physically-based approach. The present study compares empirico-statistical methods with geostatistical methods for predicting soil depth in such a landscape: Aruvikkal catchment (9.5 km²) in the Western Ghats of Kerala, India. Regression kriging applied on blocks of 20 m by 20 m using the environmental covariates elevation, slope, aspect, curvature, wetness index, land use and distance from streams, proved to be the best predictor of soil depth. This model explains 52% of the variability of soil depth in the catchment; with a prediction variance of 0.05 to 0.19. A Gaussian simulation was attempted for a more realistic visualization of the depth, as opposed to the smooth kriging prediction. The most important explanatory variable of soil depth in this landscape is land use, as expected from the strong human intervention.     

Traditional versus improved agroforestry systems in Vietnam: a comparison

Combined with the diverse biophysical and social heterogeneity encountered in the northern mountains, the socioeconomic changes in Vietnam that accompanied the decollectivisation process led to complex agrarian dynamics that today challenge traditional farming and management of natural resources. Data for this study were collected from villages in and around Ba Be National Park (BNP) in the Bac Kan Province located in the northern mountains of Vietnam. Traditional slash and burn cultivation is no longer a sustainable practice in Vietnam. The main challenges in the region are to protect biodiversity, maintain the land productivity and simultaneously support local livelihoods. The study shows that improved agroforestry cultivation could provide significantly higher productivity and income per unit of land, besides decreasing pressure on natural forests. The challenge to protect biodiversity is not met, as improved agroforestry implies less tree species. From an institutional and socio‐economic perspective, it is not easy for local communities to readily adapt to improved agroforestry. New systems must be tailored site‐specific to the diverse local conditions of resource‐poor farmers. Copyright © 2006 John Wiley & Sons, Ltd.     

Genetics of resistance to Sesamia inferens infestation and its correlation with yield in maize

Sesamia inferens (Walker) causes 25.7–78.9% losses in maize production in South and South‐East Asia. The genetic basis of host plant resistance is the prerequisite for resistance breeding. Twenty‐four populations derived from S. inferens resistant × susceptible inbreds were used to study the genetic regulation of resistance to S. inferens in maize, to determine the importance of genetic effects through generation mean analysis (GMA) and to understand correlation between resistance and yield. Resistant and susceptible inbreds differed significantly in leaf and stem injury ratings (LSIR), a measure of host plant resistance. Mean LSIR range among resistant and susceptible parents was 2.15–2.55 and 7.83–8.22, respectively. The broad‐sense heritability ranged from 0.40 to 0.71, and the mean number of effective factors ranged from 1.9 to 2.6. The resistance against S. inferens was largely governed by additive × additive (i), followed by dominance (d) and additive (a) gene effects. Significant negative correlation (?0.27 to ?0.96) was observed between LSIR and yield. The findings suggest reciprocal recurrent selection for development of new inbreds with resistance followed by their involvement in hybrid development to exploit additive and non‐additive gene effects/variance.     

Ethnobotanical flora used by four major tribes of Koraput, Odisha, India

The aim of this study is to chronicle the utilization pattern of a number of plant species by four major tribes inhabiting in Koraput district of Odisha, India. Fifteen villages dominated by tribal communities, under five Community Development Blocks were selected. A semi structured questionnaire was developed to bring together data on traditional crops and forest species still used by the communities. The methodology engaged was personal discussions with mixed focused groups combined with field visits, photographs, voice recordings and collection of materials. Findings were that tribal communities cultivate a diverse crop species with varying durations to meet their food and economic requirement throughout the year. This was supplemented by wild food collections during scarcity periods. Various forest species provide wood, fibre, leaves and grasses for agriculture, house construction and specific uses besides enhancing household income. Tribal health care practitioners collect medicinal plants from the wild and semi wild to treat both humans and livestock. At the end of the study the team assumed that tribal communities would continue to depend on traditional crops and wild forest foods for their household consumption and a diverse species of plants for other specific use. Conservation of these valuable resources in its natural habitat would be an appropriate approach for ensuring food security of future generations. Conventional plant breeders and biotechnologists should undertake scientific validation of these crops and plants to make their value explicitly known. This knowledge could be utilized for crop improvement and bio-prospecting. There is also scope for equitable sharing of benefits if used by the seed and pharmaceutical industries in future.     

Local versus expert knowledge in forest management in a semi‐arid part of India

This study analyzes the differences between the villagers' and the Forest Department's preferences in the choice of tree species to be planted in eastern Rajasthan, India. Locals learned to manage the tree resources in a sustainable manner before the formal knowledge perspectives started to dominate through various state forestry programmes in which decision making is dominated by expert perspectives in a given political context. The study also attempts to identify the problems of complementary relationships between local and expert knowledge and the resulting management implications. Copyright © 2004 John Wiley & Sons, Ltd.     

Rheological,Physico-chemical,and Surface-Active Properties of Gelatin Extracted from Bigeye Tuna (Thunnus obesus) Skin Waste

ABSTRACT

In the present investigation, bigeye tuna (Thunnus obesus) skin waste was utilized for the extraction of gelatin. Physico-chemical, rheological, and surface-active properties of the obtained gelatin were assessed. Proximate compositional analysis of tuna skin gelatin recorded high protein content of 88.6% and low levels of fat and ash contents. The isoelectric point (IEP) of tuna skin gelatin was around 6.24. Amino acid profiling recorded a glycine [31.7%] higher proportion, followed by imino acids (hydroxyproline + proline) [18.4%], and alanine [12.2%]. The electrophoretic pattern of purified gelatin exhibited three major bands (β, α1, and α2) with wider molecular weight distribution in the range of 200–120 kDa. The Fourier Transform Infrared (FT-IR) spectra of gelatin also confirmed the bands corresponding to α helix, β sheet, and random coil structures. The rheological studies of tuna skin gelatin revealed Newtonian and shear thickening properties. The method of extraction and assessment of its characteristic properties could be useful in the field of formulation of functional foods, nutraceutical, and biomedical applications.     

Harmonised monitoring of Lake Macro Prespa as a basis for Integrated Water Resources Management

In this paper, reliable data and information as an important basis for integrated water resources management (IWRM) is discussed. Such data are especially important in transboundary water bodies, as they can represent a common and transparent knowledge-base that all concerned parties can trust and utilise in the management process. The transboundary Lake Macro Prespa (West Balkan) is used as a case study. The lake is rich in biodiversity but threatened by increased eutrophication. The main focus of the monitoring (2007–2008) was therefore on nutrients and chlorophyll a, as well as oxygen levels, transparency and temperature. The results of the monitoring were used in consultations with water managers and other stakeholders, and the study demonstrated how such data could represent a common and neutral point of departure for discussions across borders on integrated lake management. However, the paper also shows that monitoring may result in inadequate or even erroneous information, thus pointing to the importance of understanding all phases of the practical implementation of harmonised monitoring. The main challenges of the harmonised monitoring included different laboratory methods and performances, as well as a number of practical issues related to logistics and communications across borders. A less ambitious programme during the first year of monitoring (2007) might have saved funds and resulted in more harmonised and reliable data this year. However, in 2008 the project succeeded in producing a set of harmonised data, amongst others by using one common and accredited laboratory for stations in both countries. This paper therefore also presents new monitoring data from this unique large lake, of which there are relatively few published studies. The results of the monitoring give reasons for concern. The eutrophication of the lake seems to be increasing, and this calls for improved integrated management in order to reduce nutrient levels and improve the environmental status.