Seed morphology and cytogenetic characterization of an endangered wild cotton,Gossypium turneri Fryxell,from Mexico

Cotton (genus Gossypium) is an important agricultural crop around the world because of its fiber. Gossypium turneri Fryxell is a wild cotton species endemic to the state of Sonora (northwestern Mexico), whose status has been recently raised to endangered in the IUCN Red List. This species has invaluable characteristics that could be useful in the cultivated cotton gene pool. Despite its importance, G. turneri has been studied very little. To the best of our knowledge, no previous study has characterized its seed morphology and cytogenetics. Therefore, in the present study the seed morphology and karyotype of G. turneri were analyzed. Seeds of G. turneri have nonuniform oval shape and brown-gray color. This species produces short fibers attached to its seed surface that are not long enough for commercial use. Our seed sizes were greater than those previously described for G. turneri and other diploid cottons. The length and width of seeds were 8.80 mm and 4.83 mm, respectively. Traits such as embryo and seed coat were measured and carefully observed, and gossypol glands were observed only in the embryo during the evaluation of internal features of seeds. Cytogenetic analysis revealed 26 chromosomes (2n?=?2x?=?26) in mitotic cells of G. turneri. The karyotype analysis showed mainly metacentric (m), submetacentric (sm) and subtelocentric (st) chromosomes. Our results reveal important biological traits of G. turneri that could be considered in future studies to improve cultivated cotton.

     

Airborne multi-spectral imagery for mapping cruciferous weeds in cereal and legume crops

Cruciferous weeds are competitive broad-leaved species that cause losses in winter crops. In the present study, research on remote sensing was conducted on seven naturally infested fields located in Córdoba and Seville, southern Spain. Multi-spectral aerial images (four bands, including blue (B), green (G), red (R) and near-infrared bands) taken in April 2007 were used to evaluate the feasibility of mapping cruciferous patches (Diplotaxis spp. and Sinapis spp.) in winter crops (wheat, broad bean and pea) and compare the accuracy of different supervised classification methods (vegetation indices, maximum likelihood and spectral angle mapper). The best classification method was selected to develop site-specific cruciferous treatment maps. Cruciferous patches were efficiently discriminated with red/blue (R/B) and blue/green (B/G) vegetation indices and the maximum likelihood classifier. At all of the locations, the accuracy of the results obtained from the spectral angler mapper was relatively low. The cruciferous weed-classified imagery of each location were created according to the method that provided the best discrimination results and were used to obtain site-specific treatment maps for in-season post-emergence control measures or herbicide applications for subsequent years. By applying the site-specific treatment maps, herbicide savings from 71.7 to 95.4% for the no-treatment areas and from 4.3 to 12% for the low-dose herbicide were obtained.     

Development of the teleomorph of Ascochyta rabiei on culture media

Ascochyta blight caused by Didymella rabiei (anamorph: Ascochyta rabiei) is an important foliar disease of chickpea in many countries. The fungus is heterothallic and requires the pairing of two compatible mating types for the teleomorph to develop. In nature, the teleomorph only develops on chickpea debris that overwinters on the soil surface in the presence of both mating types. When natural and synthetic agar media were seeded with conidial suspensions of compatible isolates of D. rabiei from Spain and the United States and incubated under favourable conditions for teleomorph development, the teleomorph only developed on 2?% water agar amended with powdered chickpea stems or hot water extracts of chickpea stems, but not on 14 other natural or synthetic media. Ascospore isolates of D. rabiei from pseudothecia that developed on agar media were indistinguishable in cultural and morphological characteristics from isolates of the fungus from chickpea. Production of pseudothecia and ascospores on the best culture medium was always lower than on stem pieces of chickpea straw used as a control treatment. Ascospores discharged from pseudothecia that developed on powdered chickpea stem media onto chickpea seedlings were pathogenic, inducing symptoms identical to those caused by ascospores from chickpea stem pieces or conidia from a chickpea isolate of the fungus. This is the first report of the teleomorph of D. rabiei developing on culture media.     

New Ikarugamycin Derivatives with Antifungal and Antibacterial Properties from Streptomyces zhaozhouensis

A bioassay guided fractionation of the ethyl acetate extract from culture broths of the strain Streptomyces zhaozhouensis CA-185989 led to the isolation of three new polycyclic tetramic acid macrolactams (1–3) and four known compounds. All the new compounds were structurally related to the known Streptomyces metabolite ikarugamycin (4). Their structural elucidation was accomplished using a combination of electrospray-time of flight mass spectrometry (ESI-TOF MS) and 1D and 2D NMR analyses. Compounds 1–3 showed antifungal activity against Aspergillus fumigatus, Candida albicans and antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA).     

Early season weed mapping in sunflower using UAV technology: variability of herbicide treatment maps against weed thresholds

Site-specific weed management is defined as the application of customised control treatments only where weeds are located within the crop-field by using adequate herbicide according to weed emergence. The aim of the study was to generate georeferenced weed seedling infestation maps in two sunflower fields by analysing overlapping aerial images of the visible and near-infrared spectrum (using visible or multi-spectral cameras) collected by an unmanned aerial vehicle (UAV) flying at 30 and 60 m altitudes. The main tasks focused on the configuration and evaluation of the UAV and its sensors for image acquisition and ortho-mosaicking, as well as the development of an automatic and robust image analysis procedure for weed seedling mapping used to design a site-specific weed management program. The control strategy was based on seven weed thresholds with 2.5 steps of increasing ratio from 0 % (herbicide must be applied just when there is presence or absence of weed) to 15 % (herbicide applied when weed coverage >15 %). As a first step of the imagery analysis, sunflower rows were correctly matched to the ortho-mosaicked imagery, which allowed accurate image analysis using object-based image analysis [object-based-image-analysis (OBIA) methods]. The OBIA algorithm developed for weed seedling mapping with ortho-mosaicked imagery successfully classified the sunflower-rows with 100 % accuracy in both fields for all flight altitudes and camera types, indicating the computational and analytical robustness of OBIA. Regarding weed discrimination, high accuracies were observed using the multi-spectral camera at any flight altitude, with the highest (approximately 100 %) being those recorded for the 15 % weed threshold, although satisfactory results from 2.5 to 5 % thresholds were also observed, with accuracies higher than 85 % for both field 1 and field 2. The lowest accuracies (ranging from 50 to 60 %) were achieved with the visible camera at all flight altitudes and 0 % weed threshold. Herbicide savings were relevant in both fields, although they were higher in field 2 due to less weed infestation. These herbicide savings varied according to the different scenarios studied. For example, in field 2 and at 30 m flight altitude and using the multi-spectral camera, a range of 23–3 % of the field (i.e., 77 and 97 % of area) could be treated for 0–15 % weed thresholds. The OBIA procedure computed multiple data which permitted calculation of herbicide requirements for timely and site-specific post-emergence weed seedling management.     

Estimation of goat production potential and efficiency in the resource-poor communal areas of the Eastern Cape Province of South Africa

It is often inappropriately assumed that the contributions of goats to household economies are similar across flock sizes. A monthly questionnaire was administered to 19, 21, and 13 farmers in Matatiele and Qawukeni and Mankone. Entries and exits to and from each flock were assessed. Most (P < 0.05) kids were born in August (4.92 ± 0.362 and 2.03 ± 0.329 for large and small flocks, respectively). Total entries were higher (P < 0.05) in August, September, and October than in the other months. Kid mortality peaked in May and September at 21%. Most (P < 0.05) goats were sold in December (1.06 ± 0.127 for large flocks and 0.23 ± 0.135 for small flocks). Goat production efficiency (GPE) was affected (P < 0.05) by month and flock size. The GPE was higher (P < 0.05) in small than in large flocks. The low GPE values obtained in this study indicates the need to devise other indices that factor in the neglected functions of goats when measuring goat production efficiency in communities where the main function of goats is not for sale or consumption.     

Cervical Vertebral Trabecular Bone Mineral Density in Great Danes With and Without Osseous‐Associated Cervical Spondylomyelopathy

Background

Great Danes (GDs) with osseous‐associated cervical spondylomyelopathy (CSM) have osteoarthritis (OA) of the cervical vertebrae. OA is often associated with increases in bone mineral density (BMD) in people and dogs.

Hypothesis/Objectives

To compare the trabecular BMD of the cervical vertebrae between clinically normal (control) GDs and GDs with osseous‐associated CSM by using computed tomography (CT). We hypothesized that the vertebral trabecular BMD of CSM‐affected GDs would be higher than that of control GDs.

Animals

Client‐owned GDs: 12 controls, 10 CSM affected.

Methods

Prospective study. CT of the cervical vertebral column was obtained alongside a calibration phantom. By placing a circular region of interest at the articular process joints, vertebral body, pedicles, and within each rod of the calibration phantom, trabecular BMD was measured in Hounsfield units, which were converted to diphosphate equivalent densities. Trabecular BMD measurements were compared between CSM‐affected and control dogs, and between males and females within the control group.

Results

Differences between CSM‐affected and control dogs were not significant for the articular processes (mean = −39; P = .37; 95% CI: −102 to 24), vertebral bodies (mean = −62; P = .08; 95% CI: −129 to 6), or pedicles (mean = −36; P = .51; 95% CI: −105 to 33). Differences between female and male were not significant.

Conclusions and Clinical Importance

This study revealed no difference in BMD between control and CSM‐affected GDs. Based on our findings no association was detected between cervical OA and BMD in GDs with CSM.