Yield and Nutrient Content of Chestnut (<Emphasis Type="Italic">Castanopsis piriformis</Emphasis>) in Natural Central Highlands Forests,Vietnam

Chestnuts have historical importance as a food source worldwide. Planting of chestnuts has focused on a few species, including Castanea dentata, Castanea sativa, Castanea mollissima, and Castanea crenata, although others species are also edible. Castanea species are members of the beech family (Fagaceae) and are native to tropical and temperate areas. In this study, the yield and nut quality of Castanopsis piriformis in natural forests of the Central Highlands of Vietnam were investigated to provide evidence that C. piriformis is worth growing as a food species. Data were collected from 12 plots of 50 m × 50 m size located in four altitude zones. Nuts were collected from three to five chestnut trees in each plot judged to be of typical sized based on diameter at breast height and crown diameter. Average dry yield of nuts was found to be elevation-dependent, being highest at 500–1000 m (1152 kg/ha/year), decreasing to 815 kg/ha/year below 500 m, and to 770 kg/ha/year at 1000–1500 m. The lowest yield was observed at above 1500 m (252 kg/ha/year). Protein and lipid contents in the kernels of C. piriformis chestnut were 4.4 and 0.1 %, respectively. Glucose accounted for 73.1 % and was significantly higher than that of commercially grown Castanopsis boisii chestnuts in Northern Vietnam. With the current price of 0.6 US$/kg nuts, collecting nuts growing in natural forest can bring at least 480 US$/ha/year to local people. These results indicate the possibility of growing and consuming C. piriformis chestnut as a crop to decrease poverty. However, governmental support is required for the sustainable development of C. piriformis.     

The potential role of an inactivated thermostable vaccine in the control of Newcastle disease in traditionally free-roaming poultry in Central and West Africa

In spite of the clinical and economic importance of Newcastle disease (ND), vaccination of traditional poultry flocks is not a common practice in Cameroon and other countries in West and Central Africa. This study was designed to demonstrate the importance of vaccination against ND and to propose a sustainable vaccination programme with a LaSota strain of NDV vaccine (Multivax) produced in Cameroon. It consisted of field vaccination trials, determination of a strategic vaccination programme through sero-monitoring and assessing vaccine keeping quality under field conditions. Twelve months monitoring of vaccinated flocks revealed that the epidemic periods of March–April and December–January passed without major incidence in flocks. Mortalities were reduced from above 90% in previous years to 10.8% and 24.6% in two experimental sites respectively. Vaccination antibodies were sustained above protection threshold for about 80 days. A booster administered 35 days after the priming dose did not have any effect on declining serum antibodies. The vaccine remained efficacious in eliciting antibody production for up to 10 weeks after initial use and kept at ambient temperature averaging 34°C. For good protection in a less intense vaccination programme, it would be necessary to administer the vaccine one month to the anticipated month of epidemic, thus requiring at least two campaigns per year.     

Needed: Regional Inventories of Organic Residuals

? As waste management planners seek to divert increasing amounts of materials from the municipal and commercial streams, the value of regions conducting inventories of organic residuals that could be composted becomes apparent. Since 1960, various research studies have analyzed the potential for applying urban wastes on agricultural lands, either directly or after composting. Specific studies described in this report were conducted in New Jersey, Maine and the Omaha, Nebraska — Council Bluffs, Iowa region.     

The effects of burning forest biomass on the yield of plantain (cv. Ebang,Musa spp. AAB,false horn) after hot-water and boiling-water treatment in southern Cameroon

Plantain grown after forest slash-and-burn raises concerns due to the release of CO₂ and the destruction of biodiversity. Plantain yields are presented after forest biomass was burned or retained in combination with sucker sanitation versus traditional planting. Biomass burning did not affect plant crop and total yield. Soil chemical properties were weakly positively affected by burning. Sucker sanitation increased total yield at one site from 6.2 to 9.7 Mg ha^?1 (p = 0.015), without effects on root health. In the second site, sucker sanitation had no effect on fresh bunch yield (mean 8.59 Mg ha^?1), yet significantly improved root health parameters. Thus, at the first site, sucker sanitation elicited a positive response via a mechanism different from nematode control. At the second site, by contrast, nematode control was not the most important factor in yield formation. These data do not support the notion that retaining biomass increases plantain production. Other factors related to labor requirements and later weed infestation are probably more important in farmers' decision making on biomass management.     

Influence of binder type on leaching rate and ingestion of microbound diets by mud crab, Scylla serrata (Forsskål), larvae

Microbound diets (MBD), composed of nutrients held within a matrix or binder, were shown to be readily ingested by larvae of the mud crab, Scylla serrata (Forsskål). In an effort to improve experimental MBD developed for S. serrata larvae, this study determined the effects of various binders on estimated larval ingestion of MBD as well as their leaching rates. Microbound diets with the same dietary compositions were bound with either agar, alginate, carrageenan, gelatin or zein. All diets contained ¹⁴C‐labelled rotifers and were fed to Zoea I, III, V larvae and megalopae. The ¹⁴C content of larvae fed ¹⁴C‐labelled MBD for 2 h was used to estimate the relative ingestion rates of MBD. For all larval stages tested, the estimated mean larval ingestion of MBD did not differ significantly between binder types (P>0.05). Determination of the amount of ¹⁴C‐labelled nutrient leaching from MBD bound with various binders after 30, 60 and 240 min of immersion showed that for all types of binders, ¹⁴C leaching occurred primarily within the first 30 min of immersion. Zein‐bound MBD consistently showed the lowest numerical leaching rate among the five binders tested for all immersion periods examined, and the differences compared with other binders were often significant, particularly after 60 and 240 min of immersion. Larval feeding experiments showed that MBD prepared with binders showing higher rates of leaching were not utilized to a greater degree by S. serrata larvae. Furthermore, unnecessary leaching from MBD particles wastes dietary nutrients and is likely to impact on water quality. On this basis, our results suggest that because of its consistently lower leaching rates, zein is probably a more suitable binder for MBD developed for S. serrata larvae.     

Evaluation of seven essential oils identifies cubeb oil as most effective attractant for detection of Xyleborus glabratus

Redbay ambrosia beetle, Xyleborus glabratus, is an exotic wood-borer that vectors the fungal agent that induces laurel wilt. Since its introduction into Georgia in 2002, X. glabratus has spread throughout the southeastern U.S., and laurel wilt has decimated native Persea trees, particularly redbay (P. borbonia) and swampbay (P. palustris). The lethal disease now threatens avocado (P. americana) in Florida. To control the spread of laurel wilt, effective attractants are needed for early detection of the vector. Phoebe oil lures are the best known attractant, but they are no longer available. Current detection relies on manuka oil lures, but our previous research indicated they have a field life of only 2–3 weeks in Florida. Therefore, we evaluated seven essential oils as attractants for X. glabratus, and ethanol as a potential synergist. Field tests and electroantennography (EAG) were conducted to compare attraction and olfactory response to angelica seed, cubeb, ginger root, manuka, phoebe, tea tree, and orange oils. The highest captures were obtained with cubeb, manuka, and phoebe oils; ginger and angelica oils were intermediate, and tea tree and orange oils were not attractive. Addition of ethanol to oil lures did not increase captures. In subsequent tests with commercial formulations, cubeb lures captured more X. glabratus than manuka lures, were better for early detection at low population levels, and had longevity of at least 8 weeks. The highest EAG responses were elicited with phoebe and cubeb lures. Our results indicate that cubeb lures are the best attractant currently available for detection of X. glabratus.     

Species-site matching in mixed species plantations of native trees in tropical Australia

Mixed species plantations using native trees are increasingly being considered for sustainable timber production. Successful application of mixed species forestry systems requires knowledge of the potential spatial interaction between species in order to minimise the chance of dominance and suppression and to maximise wood production. Here, we examined species performances across 52 experimental plots of tree mixtures established on cleared rainforest land to analyse relationships between the growth of component species and climate and soil conditions. We derived site index (SI) equations for ten priority species to evaluate performance and site preferences. Variation in SI of focus species demonstrated that there are strong species-specific responses to climate and soil variables. The best predictor of tree growth for rainforest species Elaeocarpus grandis and Flindersia brayleyana was soil type, as trees grew significantly better on well-draining than on poorly drained soil profiles. Both E. grandis and Eucalyptus pellita showed strong growth response to variation in mean rain days per month. Our study generates understanding of the relative performance of species in mixed species plantations in the Wet Tropics of Australia and improves our ability to predict species growth compatibilities at potential planting sites within the region. Given appropriate species selections and plantation design, mixed plantations of high-value native timber species are capable of sustaining relatively high productivity at a range of sites up to age 10 years, and may offer a feasible approach for large-scale reforestation.     

Molecular mapping of the leaf rust resistance gene rph6 in barley and its linkage relationships with rph5 and rph7

ABSTRACT The barley cv. Bolivia carries two leaf rust (Puccinia hordei) resistance genes, Rph2 and Rph6, and is the only known source of the latter gene. A resistant line (Bolivia-Rph6) carrying Rph6 only was obtained in the F(4) generation of a cross between cv. Bolivia and the susceptible cv. Bowman via progeny testing with differential isolates of the leaf rust pathogen. Genetic analyses and bulk segregant analysis using amplified fragment length polymorphism (AFLP) and restriction fragment length polymorphism (RFLP) markers localized Rph6 on the short arm of barley chromosome 3H at a distance of 4.4 centimorgans (cM) distal from RFLP marker MWG2021 and 1.2 cM proximal from RFLP marker BCD907. The allelic relationship of Rph6 to other leaf rust resistance genes mapping to this region of chromosome 3H (namely Rph5 and Rph7) were tested using crosses among cvs. Magnif 102 (carrying Rph5), Bolivia-Rph6 (Rph6), and Cebada Capa (Rph7). Segregation analyses indicated that Rph6 is allelic to Rph5 and closely linked to Rph7. The data generated from this study will facilitate breeding for leaf rust resistance via marker-assisted selection and provide a starting point for positional gene cloning.