Effect of Pheromone Blend Components,Sex Ratio,and Population Size on the Mating of Cadra cautella (Lepidoptera: Pyralidae)

The almond moth Cadra cautella (Walker), a key pest of storage facilities, is difficult to manage using synthetic chemicals. Pheromone-based management methods remain a high priority due to advantages over conventional management practices, which typically use insecticides. Cadra cautella females release a blend of pheromone including (Z, E)-9,12-tetradecadienyl acetate (ZETA) and (Z)-9-tetradecadien-1-yl acetate (ZTA). The effect of these components on mating of C. cautella and how response varies with the population density and sex ratio remain unknown. In this study, the mating status of C. cautella was studied inside mating cages under different ratios of ZETA and ZTA diluted in hexane and at different population sizes either with equal or unequal sex ratio. The lowest percentage of mated females (highest mating disruption [MD] effects), corresponding to roughly 12.5%, was produced by a 5:1 and 3.3:1 ratio of ZETA:ZTA. Populations with equal sex ratio showed the lowest percentage of mated females, at 20% and 12.5% under lower and higher density, respectively. The next lowest percentage of mated females was produced when the sex ratio was set to 1: 2 and 2:1 male:female, with just 25% and 22.5% of moths mated, respectively. This study shows that mating status of C. cautella is influenced by ZETA:ZTA ratio, sex ratio, and population size. This current knowledge would have useful implications for mating disruption programs.     

Pectin purified from pomelo (Citrus maxima) peel as a natural hatching agent for fish embryos

Pectin is a biodegradable polysaccharide, and it has been recently applied as a gene delivery, drug delivery, wound healing and tissue engineering agent. In this study, pectin was extracted from pomelo (Citrus maxima) peel and characterized. The extraction recovery of pectin form pomelo peel was 14.5%, and it had 72.56% degree of esterification, 1,245.56 equivalent weight, 7.82% methoxyl and 68.27% anhydrouronic acid contents. Use of pomelo pectin as a hatching enhancing agent for fish embryos and its effect on hatching enzyme 1 (ZHE1) was investigated. The pectin‐exposed zebrafish embryos (100 µg/ml) showed significantly (p < .05) higher hatching rate (96.6%) compared with untreated (control) embryos (66.6%) at 60 hpf. The mRNA expression of ZHE1 was also significantly (p < .05) elevated up to 55.6‐fold in pectin‐exposed embryos at 24 hpf. In situ hybridization results revealed remarkably strong expression of ZHE1 in pectin‐exposed embryos compared with the control group. In addition, considerably larger size of the hatching gland was observed in pectin‐exposed larvae than that of the unexposed larvae group. These results clearly indicate that pectin isolated from pomelo peel has an ability to enhance the hatching process of zebrafish embryos via upregulation of ZHE1.     

Wheat grain quality under increasing atmospheric CO2 concentrations in a semi-arid cropping system

We investigated wheat (Triticum aestivum) grain quality under Free Air CO₂ Enrichment (FACE) of 550 ± 10% CO₂ μmol mol⁻¹. In each of two full growing seasons (2008 and 2009), two times of sowing were compared, with late sowing designed to mimic high temperature during grain filling. Grain samples were subjected to a range of physical, nutritional and rheological quality assessments. Elevated CO₂ increased thousand grain weight (8%) and grain diameter (5%). Flour protein concentration was reduced by 11% at e[CO₂], with the highest reduction being observed at the late time of sowing in 2009, (15%). Most of the grain mineral concentrations decreased under e[CO₂] - Ca (11%), Mg (7%), P (11%) and S (7%), Fe (10%), Zn (17%), Na (19%), while total uptake of these nutrients per unit ground area increased. Rheological properties of the flour were altered by e[CO₂] and bread volume reduced by 7%. Phytate concentration in grains tended to decrease (17%) at e[CO₂] while grain fructan concentration remained unchanged. The data suggest that rising atmospheric [CO₂] will reduce the nutritional and rheological quality of wheat grain, but at high temperature, e[CO₂] effects may be moderated. Reduced phytate concentrations at e[CO₂] may improve bioavailability of Fe and Zn in wheat grain.     

Papaya yellow leaf curl virus: A newly identified begomovirus infecting Carica papaya L. from the Indian Subcontinent

India is one of the world’s largest producers of papaya. Viruses, mainly begomoviruses and potyviruses, cause a significant loss in papaya production. The study described here has identified a new species of begomovirus and a new species of betasatellite infecting Carica papaya in India. The sequences of the begomovirus and betasatellite show 90.03% nucleotide sequence identity to an isolate of Radish leaf curl virus and 92.25% identity to an isolate of Tomato leaf curl betasatellite, respectively. Maximum likelihood phylogenetic tree of begomovirus sequence of isolate DP2 (KX353622) showed distant relationships with previously characterised begomoviruses. Recombination analysis proposed six recombination breakpoints in begomovirus genome with other geographical begomovirus isolates.     

Segmentation of 3D images of plant tissues at multiple scales using the level set method

Background

Developmental biology has made great strides in recent years towards the quantification of cellular properties during development. This requires tissues to be imaged and segmented to generate computerised versions that can be easily analysed. In this context, one of the principal technical challenges remains the faithful detection of cellular contours, principally due to variations in image intensity throughout the tissue. Watershed segmentation methods are especially vulnerable to these variations, generating multiple errors due notably to the incorrect detection of the outer surface of the tissue.

Results

We use the level set method (LSM) to improve the accuracy of the watershed segmentation in different ways. First, we detect the outer surface of the tissue, reducing the impact of low and variable contrast at the surface during imaging. Second, we demonstrate a new edge function for a level set, based on second order derivatives of the image, to segment individual cells. Finally, we also show that the LSM can be used to segment nuclei within the tissue.

Conclusion

The watershed segmentation of the outer cell layer is demonstrably improved when coupled with the LSM-based surface detection step. The tool can also be used to improve watershed segmentation at cell-scale, as well as to segment nuclei within a tissue. The improved segmentation increases the quality of analysis, and the surface detected by our algorithm may be used to calculate local curvature or adapted for other uses, such as mathematical simulations.

     

Nursery rearing of kalbasu, Labeo calbasu (Hamilton), at different stocking densities in outdoor concrete tanks

The growth and survival of kalbasu, Labeo calbasu, was evaluated at stocking densities of 5, 10 and 15 million spawn ha⁻¹ in nursery rearing in concrete tanks of 50 m², each for a period of 25 days. Survival of fry was density dependent and significantly higher (54.5%) at 5 million ha⁻¹ than those at 10 million ha⁻¹ (50.1%) and 15 million ha⁻¹ (46.9%). Similarly, growth and specific growth rate were inversely related to the stocking density and varied significantly among the three densities.     

Intra-specific variation of wheat grain quality in response to elevated [CO2] at two sowing times under rain-fed and irrigation treatments

In order to investigate the intra-specific variation of wheat grain quality response to elevated atmospheric CO₂ concentration (e[CO₂]), eight wheat (Triticum aestivum L.)cultivars were grown at two CO₂ concentrations ([CO₂]) (current atmospheric, 389 CO₂ μmol mol⁻¹vs. e[CO₂], FACE (Free-Air CO₂ Enrichment), 550  ±  10% CO₂ μmol mol⁻¹), at two water levels (rain-fed vs. irrigated) and at two times of sowing (TOS₁, vs. TOS₂). The TOS treatment was mainly imposed to understand whether e[CO₂] could modify the effects of timing of higher grain filling temperatures on grain quality. When plants were grown at TOS₁, TKW (thousand kernel weight), grain test weight, hardness index, P, Ca, Na and phytate were not significantly changed under e[CO₂]. On the other hand, e[CO₂] increased TKW (16%), hardness index (9%), kernel diameter (6%), test weight (2%) but decreased grain protein (10%) and grain phytate (11%) at TOS₂. In regard to grain Zn, Mn and Cu concentrations and some flour rheological properties, cultivar specific responses to e[CO₂] were observed at both sowing times. Observed genetic variability in response to e[CO₂] in terms of grain minerals and flour rheological properties could be easily incorporated into future wheat breeding programs to enable adaptation to climate change.     

Variation of Phyllosphere Microflora of Different Rice Varieties in Sri Lanka and its Relationship to Leaf Anatomical and Physiological Characters

Anatomical and physiological characters of the leaf surface and its physico‐chemical environment substantially influence the density and diversity of phyllosphere‐inhabiting microorganisms, which may include natural antagonists of important pathogens. The objective of this investigation was to quantify the phyllosphere (i.e. leaf surface) microbial population in a range of rice varieties grown in Sri Lanka and to identify the leaf anatomical and physiological characters that determine the density and diversity of phyllosphere microbes. Fifteen rice varieties including both traditional and new high‐yielding varieties were used in a planthouse experiment and a field experiment in two consecutive seasons to quantify the phyllosphere microbial population and measure leaf characters that may influence it. There were highly significant intervarietal variations in the density and diversity of epiphytic bacterial, fungal and total microbial populations under both planthouse and field conditions. However, there was no difference between traditional and new, high‐yielding varieties in their capacity to harbour epiphytic microbes in the phyllosphere. Total microbial density (TMD) under both conditions showed positive correlations with leaf hair density, stomatal density and transpiration rate. Under planthouse conditions, TMD was also positively correlated with leaf hair length and negatively correlated with leaf temperature. These correlations can be explained in terms of providing favourable microsites on the phylloplane for epiphytic microbial growth.     

Rice-wheat productivity and nutrient status in a lantana- (Lantana spp.) amended soil

Imbalanced and inadequate use of chemical fertilizers is responsible for low rice- (Oryza sativa L.) wheat (Triticum aestivum L.) productivity in many resource-poor farmers' fields. Wheat yields in post-rice soils are also constrained due to soil conditions created by puddling in rice, especially in fine to medium textured soils. Organic amendments are known to improve soil productivity under rice-wheat cropping by way of improving physical conditions and nutrient status of the soil, but their availability is restricted. There is a need to identify locally available and cost-effective organic materials, which have minimal alternate uses as fodder and fuel. We evaluated lantana (Lantana spp. L.) residues, a fast-growing weed in nearby wastelands, as a potential soil organic amendment. Yield trends, and soil and crop nutrient status in a 12-year rice-wheat experiment at Palampur, India, involving four levels (0, 10, 20, and 30 Mg ha^-1 year^-1 fresh mass) of lantana addition were investigated. Chopped lantana was incorporated into soil 10–15 days before puddling. Lantana additions at 10, 20 and 30 Mg ha^-1 increased rice yields on average by 18%, 23% and 30%, wheat yields by 11%, 14% and 20%, and total system productivity (rice + wheat) by 15%, 20% and 26% over controls, respectively, and at the same time saved NPK fertilizer. Linear regression analyses over 12 years did not show any change in yield trends of rice and wheat at P =0.05. Continuous cultivation of rice-wheat significantly increased total C, labile C, and other C indices of soils. Total N, Olsen's P, and NH₄OAc-extractable K in the lantana-amended plots were higher than in the controls. Nutrient concentrations in crop biomass, however, remained generally unaffected by lantana treatments. Results suggest that lantana residues, which improved the nutrient status of soil and system yield, have the potential for resource conservation and sustaining rice-wheat productivity.