Machine vision smart sprayer for spot-application of agrochemical in wild blueberry fields

An essential part of the wild blueberry cropping system is the proper management of agrochemical inputs including herbicides, fungicides and insecticides. A machine vision system was developed and mounted on the rear sprayer boom 0.18 m in front of the sprayer nozzles capable of targeting the agrochemical application on an as-needed basis. The three-point hitch mounted sprayer featured 27 nozzles over a 13.7 m boom width and a storage tank capacity of 1135 l. Nine digital color cameras continually take images in real-time while computer software processes the images in 0.15 s to determine the target locations where the nozzles open and spray at speeds up to 1.77 m s^?1. Two wild blueberry fields in central Nova Scotia were selected for smart sprayer performance testing with spot-application (SA) of agrochemical as compared to control and uniform application techniques. Chateau^® herbicide was applied in a field with an infestation of hair cap moss. Spray droplet comparison showed moss patches were properly targeted using the smart sprayer. SA provided the same coverage performance as compared to uniform on the moss targets with herbicide application savings of 78.5% using the smart sprayer. Harvestable yield results were similar for all application tracks. TruPhos Magnesium and ZincMax foliar fertilizers were tank mixed with Bravo^® and Proline^® fungicides and applied to compare the difference of SA, control and uniform application. Results showed SA of foliar fertilizer and fungicide led to less premature leaf drop and increased the blueberry stem height, number of branches, stem diameter and fruit buds. SA of foliar fertilizer and fungicide also increased the percent of healthy wild blueberry plants by 57.8% and the harvestable yield by 137.8%. Fungicide application savings using the smart sprayer for SA were 11.6%.     

Verrucosamide,a Cytotoxic 1,4-Thiazepane-Containing Thiodepsipeptide from a Marine-Derived Actinomycete

A new cytotoxic thiodepsipeptide, verrucosamide (1), was isolated along with the known, related cyclic peptide thiocoraline, from the extract of a marine-derived actinomycete, a Verrucosispora sp., our strain CNX-026. The new peptide, which is composed of two rare seven-membered 1,4-thiazepane rings, was elucidated by a combination of spectral methods and the absolute configuration was determined by a single X-ray diffraction study. Verrucosamide (1) showed moderate cytotoxicity and selectivity in the NCI 60 cell line bioassay. The most susceptible cell lines were MDA-MB-468 breast carcinoma with an LD₅₀ of 1.26 µM, and COLO 205 colon adenocarcinoma with an LD₅₀ of 1.4 µM. Also isolated along with verrucosamide were three small 3-hydroxy(alkoxy)-quinaldic acid derivatives that appear to be products of the same biosynthetic pathway.     

Synergy between grapevine vitiviruses and grapevine leafroll viruses

An interactive relationship between vitiviruses and grapevine leafroll viruses was characterized in grapevine. Grapevine viruses A and B (GVA and GVB) were found more frequently in the presence of co-infecting Grapevine leafroll associated viruses (GLRaV-1, ?2 or ?3) than in their absence. The titers of the vitiviruses in co-infection with leafroll viruses were found to be higher than were their titers in the absence of leafroll virus infection. The occurrence of vitivirus-associated stem-pitting symptoms was correlated with leafroll virus co-infection. Specific pairing associations on the species level were found between different viti- and leafroll virus species: GVB was associated preferentially with GLRaV-2; GVA was associated preferentially with GLRaV-1 and GLRaV-3. In contrast to the increase in vitivirus titer seen with leafroll virus co-infection, the incidence and titer of grapevine leafroll virus appeared to be unaltered by vitivirus co-infection. The potential for a synergistic enhancement of grapevine disease in co-infected vines is discussed.     

Genetic variation in Eucalyptus camaldulensis and E. tereticornis for early growth and susceptibility to the gall wasp Leptocybe invasa in China

The gall wasp Leptocybe invasa is a major insect pest on plantation Eucalyptus in many countries. Since appearing in China in 2007 it has had major impacts on commercial plantations—some commonly planted Eucalyptus varieties have proven particularly susceptible, including hybrids involving Eucalyptus camaldulensis and E. tereticornis parent species. Intra-specific variation within each species for L. invasa susceptibility was examined in two seed source and family trials in southwest of Guangdong. The E. camaldulensis trial included 101 seedlots representing five natural stand and six seed orchard sources which also represented three sub-specific taxa. The E. tereticornis trial included 143 seedlots representing 11 natural stand and four seed orchard sources, including breeding seed orchards in China. Both trials were assessed for susceptibility to L. invasa along with height at age 9 months. Sub-specific taxa within E. camaldulensis differed significantly (P < 0.01) in L. invasa susceptibility but not height or survival; subsp. acuta had the lowest average susceptibility and subsp. simulata and obtusa were of intermediate susceptibility whilst material of uncertain sub-specific taxa from India had the highest average susceptibility. In E. tereticornis regions of origin and seed sources within regions differed significantly (P < 0.01) for both L. invasa susceptibility and height; the region China (all somewhat improved sources) had both the best average height growth and lowest susceptibility whilst the region Australia (all natural stand sources) proved inferior to China for both average susceptibility and height. A strong significant correlation was found between seed source average L. invasa susceptibility and annual rainfall at seed source geographic origin in E. tereticornis (r = ?0.873; P < 0.01), implying that seedlots from higher rainfall environments are markedly less susceptible to L. invasa. The equivalent parameter in E. camaldulensis was also strong (r = ?0.730) though not significant, perhaps due to having only five data points available. Differences between families within seed sources for both L. invasa susceptibility and height growth were also highly significant (P < 0.01) with the former trait proving moderately to strongly heritable (h _i ²  = 0.54 ± 0.40 in E. camaldulensis; 0.52 ± 0.50 in E. tereticornis). Height had low to moderate heritability in both species (h _i ²  = 0.11 ± 0.15 and 0.26 ± 0.08 respectively). Tree height and L. invasa susceptibility showed a moderate negative (favourable) genetic correlation in E. camaldulensis (?0.33 ± 0.64) and a moderate to strong negative (favourable) genetic correlation in E. tereticornis (?0.47 ± 0.31). Corresponding phenotypic correlations, though significant, were somewhat weaker (?0.16 and ?0.29 respectively), indicating a trend for taller trees to have lower levels of L. invasa susceptibility.     

Frequency and distribution of the brown rust resistance gene Bru1 and implications for the Louisiana sugarcane breeding programme

Brown rust, caused by the fungus Puccinia melanocephala, poses an increasing threat to sugarcane industries worldwide. Recently, markers R12H16 and 9020‐F4 were developed for a major resistance gene Bru1 that contributes to a significant proportion of brown rust resistance in multiple sugarcane industries. Marker‐assisted screening of Louisiana sugarcane germplasm showed a low frequency (4.3%, five out of 117 clones) of Bru1 among sugarcane cultivars and elite breeding clones. Likewise, among progeny of crosses involving wild/exotic germplasm, only 14 of 208 clones (6.7%) tested Bru1 positive. However, Bru1 frequency was higher (28.7%, 52 of 181 clones) in wild/exotic germplasm, which indicated that diverse genetic resources are available for Bru1 introgression. Commercial Bru1‐positive cultivar, ‘L 01‐299', was resistant to brown rust. However, Bru1‐positive cultivar, ‘L 10‐146’, was susceptible while Bru1‐negative cultivars, such as ‘L 99‐233’, showed resistance to brown rust. Bru1‐negative clones with brown rust resistance offer an opportunity to identify alternate sources of resistance, which can be pyramided with Bru1 for effective and durable resistance in sugarcane against the changing pathogen.     

Identifying and exploring significant genomic regions associated with soybean yield,seed fatty acids,protein and oil

Soybean [Glycine max (L.) Merrill] yield and seed fatty acids, protein, and oil content are important traits for which an improved understanding of significant genomic regions would be useful. To accomplish this, a soybean population consisting of 203 F5 derived recombinant inbred lines (RILs) was developed and genotyped with 11,633 polymorphic single nucleotide polymorphisms (SNPs). Each RIL was grown in a single plot at Knoxville, TN in 2010; followed by replicated, multi-location field trials in 2013 and 2014. The data from 2010, 2013, and 2014 were analyzed together in order to detect quantitative trait loci (QTL) for these traits, and 30 total QTLs were detected. Five QTLs are candidates for confirmed status and one QTL is a candidate for positional confirmation. Many of the genes with mutations in close proximity to the fatty acid QTLs are involved in biological processes for fatty acids and/or lipids and could be considered possible candidate genes. Similarly, genes with mutations in genomic regions near yield, protein, and oil QTLs were plentiful and may contribute to the variation observed in these traits. Except for yield and stearic acid, each trait displayed pleiotropic effects with other traits in this study. Notable are the pleiotropic effects for oleic and linolenic acid on chromosomes 9, 13, and 19. Overall, the findings from this research contribute new information to the genetic understanding of soybean yield and seed fatty acids, protein and oil content. This understanding will be useful in making trait improvements.     

Climate change impact on corn suitability in Isabela province,Philippines

Climate change is expected to affect agricultural crop production in the Philippines. Several studies were already done to quantify the effect of climate change on agricultural crop production in the country. Most of these studies focus only on the effect of climate change on crop yield. This study estimated the effect of climate change on the area (suitable area) for corn production. Using the Land Use Suitability Evaluation Tool (LUSET), change in corn suitability in the province of Isabela was estimated for the years 2050, 2060, and 2070. Based on the results, climate change will negatively impact corn suitability in the province. Decreasing trend in corn suitability rating was observed due to increasing temperature resulting to loss of highly suitable areas for corn production. For example, during the first cropping season the estimated average decreases in suitability scores due to an increase in temperature were 6.7, 11.4, and 20.7% in the years 2050, 2060, and 2070, respectively. These decreases in suitability resulted in the loss of 6,777 ha highly suitable areas for corn production.     

Comparison of the pharmacokinetics of two formulations of hydroxyethyl starch in healthy horses

A lower molecular weight and molar substitution formulation (130/0.4) of hydroxyethyl starch solution has been shown to have a more sustained effect on COP and similar hemodynamic effects as a higher molecular weight and molar substitution formulation (600/0.75) in healthy horses. In humans, these pharmacodynamic characteristics are coupled with more rapid clearance and decreased adverse coagulation effects and accumulation. The objective of this study was to determine and compare the pharmacokinetics of these two formulations in horses. Eight healthy horses were given a 10 mL/kg bolus of each formulation (600/0.75 and 130/0.4) of hydroxyethyl starch solution in a randomized crossover design. Blood was collected, and plasma was harvested for plasma levels over 24 h. Pharmacokinetic parameters for each horse were estimated from a noncompartmental analysis. Treatment with 600/0.75 resulted in a higher initial plasma concentration (C₀), systemic half‐life (t_1/2), and overall drug exposure (AUC_0–inf) in addition to decreased elimination rate (β), volume of distribution (Vd), and clearance (CL), compared to treatment with 130/0.4 (P < 0.001). The pharmacokinetic findings combined with previous pharmacodynamics findings suggest that 130/0.4 can provide similar benefits to 600/0.75 with a lower risk of accumulation in the circulation.     

Early ocean distribution of juvenile Chinook salmon in an upwelling ecosystem

Extreme variability in abundance of California salmon populations is often ascribed to ocean conditions, yet relatively little is known about their marine life history. To investigate which ocean conditions influence their distribution and abundance, we surveyed juvenile Chinook salmon (Oncorhynchus tshawytscha) within the California Current (central California [37°30′N) to Newport, Oregon (44°00′N]) for a 2‐week period over three summers (2010–2012). At each station, we measured chlorophyll‐a as an indicator of primary productivity, acoustic‐based metrics of zooplankton density as an indicator of potential prey availability and physical characteristics such as bottom depth, temperature and salinity. We also measured fork lengths and collected genetic samples from each salmon that was caught. Genetic stock identification revealed that the majority of juvenile salmon were from the Central Valley and the Klamath Basin (91–98%). We constructed generalized logistic‐linear negative binomial hurdle models and chose the best model(s) using Akaike's Information Criterion (AIC) to determine which covariates influenced the salmon presence and, at locations where salmon were present, determined the variables that influenced their abundance. The probability of salmon presence was highest in shallower waters with a high chlorophyll‐a concentration and close to an individual's natal river. Catch abundance was primarily influenced by year, mean fork length and proximity to natal rivers. At the scale of sampling stations, presence and abundance were not related to acoustic indices of zooplankton density. In the weeks to months after ocean entry, California's juvenile Chinook salmon population appears to be primarily constrained to coastal waters near natal river outlets.     

Nutrient efficacy of microalgae as aquafeed additives for the adult black tiger prawn,Penaeus monodon

This study used a small amount of several lyophilized microalgae (5% of dry weight in aquafeed) to feed adult black tiger prawns Penaeus monodon for 4 weeks, aiming to promote prawn health and nutritional level. Apart from slight increases in ash content, chlorophyll and β‐carotene in the microalgae‐added feeds, there was no difference from the commercial diet in their biochemical composition. After 28 days of feeding, prawn body length, body weight, condition index and also total amount of fatty acids and amino acids of the flesh (2nd abdominal segment) were not affected by microalgae additives as compared with the control commercial diet‐fed group (P > 0.05). Prawns fed the microalgae diets, however, had a relatively better survival rate than those fed the commercial control diet, although no statistical significance was detected in any except for the diatom Melosira sp. The elevated survival rate was concomitant with a higher phagocytosis rate and superoxide dismutase (SOD) activity in the immune response analysis, and significantly a higher astaxanthin content detected in the tail muscle of microalgae diet‐fed prawns (5.36–10.78 ng of astaxanthin per gram of muscle DW). These findings demonstrated that low‐inclusion microalgal additives in prawn diets over a short feeding period (4 weeks) can result in healthier adult prawn, and hence could contribute to the development of an optimized feeding strategy for prawn aquaculture close to harvesting.