Hybridization and heterosis in the Plicatula group of <Emphasis Type="Italic">Paspalum</Emphasis>

Most forage cultivars released for the genus Paspalum belong to a section named Plicatula. The species of Plicatula are mostly apomictic and consequently the genetic diversity is locked for their genetic improvement. The objectives were to evaluate the crossability, hybrid fertility, heterosis, and genetic distances between apomictic accessions and a sexual genotype of species of Plicatula group of Paspalum. Crosses were made using 22 apomictic tetraploid accessions belonging to 12 different species as pollen donors, and a sexual tetraploid genotype induced by colchicine from a sexual diploid accession of P. plicatulum. Crossability varied between 0 and 16% among crosses. Viable hybrid offspring were recovered from 15 out of 22 crosses. The most successful crosses involved P. guenoarum, P. plicatulum, P. chaseanum, and P. oteroi. Fertility of the sampled hybrids varied between 1.6% for the cross involving P. lenticulare, and 40.1% for an intraspecific cross (P. plicatulum, accession Hojs388). The genetic distance between parents was estimated using amplified fragment-length polymorphism, and it varied between 0.34 and 0.53. There was no correlation between genetic distances and crossability or fertility of the hybrids. Hybrids from the most numerous families were classified for mode of reproduction using flow cytometric seed analysis. The ratio between sexual and apomictic hybrids varied between 0.6:1 and 1.6:1. A selected group of apomictic hybrids were evaluated for several agronomic traits in the field. Heterosis was observed for frost tolerance and cattle preference. The results indicated that gene transfer via hybridization is possible among several species of Plicatula. Superior hybrids for specific traits can be generated and fixed by apomixis.     

A vagrant clone in a peregrine species: Phylogeography, high clonal diversity and geographical distribution in the earthworm Aporrectodea trapezoides (Dugès, 1828)

The peregrine lumbricid Aporrectodea trapezoides is originally from the Palaearctic region but is distributed worldwide. Little is known about its clonal diversity or the existence of a pattern of biogeographical diversification of clones. This study aimed to explore the evolutionary history of A. trapezoides by analysing the mitochondrial (COI and COII) and nuclear (28S rRNA and histone H3) DNA sequences of individuals collected in 11 different countries. High clonal diversity was found for this species, with thirty-seven clones clearly divided into two distinct lineages (I and II). The marked biogeographical boundary between these lineages corresponds to the line separating the Eurosiberian and Mediterranean climates in North Spain. Clone 1 was shared by one-third of the earthworms. While this clone was found in most of the sampled localities, the rest of the clones showed geographically-restricted distributions. This clone may have originated in the Mediterranean area of Central Spain. As it was obviously introduced in Australia and it was found in locations occupied by members of both lineages, we hypothesise that it may have also been introduced in other countries and that it could be a general-purpose genotype able to adapt to a wide range of niches.     

Comparative performance of winter and spring malting barleys in semiarid growing conditions

In Europe, during the 1960s, mainly two-rowed spring barley was used for malting. Traditionally, spring malting barley was produced in regions with moderate temperatures and adequate rainfall throughout the growing season. Winter malting barley, on the other hand, was mostly grown in the milder arid and semiarid parts of Europe. Due to global climatic changes and its higher yield, winter malting barley is now increasing in acreage in the traditional spring barley regions. Our study included a comparative analysis of several grain and malt characters of the winter and spring malting barley grown under the agroecological conditions of the Vojvodina Province, Yugoslavia. One thousand grain weight was shown to be approximately the same for both growth habits, whereas winter malting barley proved to have a higher hectoliter mass than the spring one. In those years that were less favorable for spring barley production, winter malting barley had better quality characters, namely a higher fine extract content, a better malt modification, and a lower malt protein content. This revised version was published online in July 2006 with corrections to the Cover Date.     

Osteosarcoma at the site of a triple pelvic osteotomy in a dog

An osteosarcoma (OSA) involving the right pelvis was diagnosed in a 12-year-old golden retriever 11 years after triple pelvic osteotomy (TPO) surgery. The dog was presented with a 12-week history of nonweight-bearing lameness of the right hind limb. Radiographs demonstrated an aggressive bone lesion of the right ilium with profound periosteal proliferation and punctate lysis that extended along the ilium caudally and into the right ischium, with its epicenter at the level of the right TPO plate. Necropsy revealed that the entire right hemipelvis, especially the ischium, was markedly thickened and firm with irregular margins. Histopathology was consistent with a diagnosis of OSA.     

Multiscale control of vegetation patterns: the case of Doñana (SW Spain)

The early studies about the plant ecology of Doñana carried out at a small scale showed that the main process controlling vegetation composition of the stabilized dunes was soil water availability. However, the extrapolation of this model to larger spatial scales failed to explain observed vegetation patterns. In this work, the vegetation patterns and the processes causing them are studied at a larger scale. Data of topography, soil pH, electrical conductivity, and available iron allowed to distinguish three large geomorphologic zones on the stabilized dunes of the Doñana Biological Reserve which correspond to different dune building episodes. Different dune episodes showed differences in both water table depth and dynamics, which are due to groundwater flow systems of different scale. It is further manifested by differences in shrub composition. The results show that geomorphology controls the vegetation pattern at different scales mediated through water availability. Differences in water availability are due to the connection to groundwater flow systems of contrasted scale. On a small scale (10−10² m), along dune slopes, there is a gradient from dune ridges to slacks, from xerophyte to hygrophyte vegetation types. On a mesoscale (10²−10³ m), there are several dune episodes with variable topographic altitude, dominated by different types of xerophytes. On a regional scale (>10³ m), the discharges of the regional aquifer produce strong environmental and biotic stresses resulting in a mixed community.     

Genetic variation for dry matter and nitrogen accumulation and translocation in two-rowed spring barley II. Nitrogen translocation

An understanding of the partition between pre-anthesis and post-anthesis N uptake and their contribution to total grain N and protein content in spring two-rowed barley (Hordeum vulgare spp. distichum L.) is important to achieve additional breeding progress for both fodder and malting barley. N translocation from the vegetative tissues at anthesis to the kernel, N translocation efficiency, and N harvest index (NHI) were studied in field experiments during 4 years (1995–1998). Plants were harvested at anthesis and maturity and divided into leaf+culm, chaff and grain. Significant cultivar differences in N translocation, N translocation efficiency and NHI were determined. Across cultivars, the highest N translocation was in a favorable year (93 kg ha⁻¹) and the lowest in a year with poor growing conditions (40 kg ha⁻¹). Cultivar differences in N translocation were related to dry matter and pre-anthesis N accumulation (R²>0.70). N translocation efficiency varied more among the cultivars (0.27–0.66) than years (0.47–0.52). Post-anthesis N uptake was negatively correlated (P<0.01) with N translocation. NHI ranged among the cultivars from 0.49 to 0.73 and among the years from 0.57 to 0.74. The cultivars Arapiles, Schooner, Cantala, Kaskade and Pek stored in the grain more than 70% and Hiproly less than 50% of above-ground N at maturity. Translocated N participated with 85, 56, 42, and 61% in grain N in 1995, 1996, 1997, and 1998, respectively. The ratio of translocated N to grain N could be an indicator of growing conditions; a higher ratio indicates good growing conditions over the entire growth period, a lower ratio indicates poor conditions during pre-anthesis, and a medium ratio indicates some temperature and water deviations from the long-term average. Straw N concentration was in significant positive (P<0.01) correlation with N translocation and translocation efficiency. Straw N concentration adequately represents N efficiency utilization for synthesis of grain protein, and because it saves time and money compared to N harvest index determination, it can be used for the testing of breeding materials for the development of new barley cultivars.     

Use of a wireless system to measure invasive arterial blood pressure in ponies – preliminary study

Objective  To evaluate the feasibility and functionality of intra-carotid wireless device implantation in ponies, and to investigate its short-term complications.
Study design  Prospective preliminary study.
Animals  Five mixed breed, adult, intact male ponies weighing 104 ± 28.8 kg (mean ± SD) underwent surgery. Arterial blood pressure data were continuously collected from four animals.
Methods  General anesthesia was induced on two consecutive days. On the first day, an intra-arterial wireless device was implanted in the right carotid artery. On the next day, a transcutaneous intra-arterial catheter was placed in the left facial artery. Data from both sources were collected. Post-mortem examination was performed.
Results  Surgical time was 27.1 ± 11.85 minutes. All catheters remained in place with some extra vascular migration. Complications included mild seroma and hematoma.
Conclusion  The wireless system allowed continuous monitoring in ponies throughout anesthesia and at rest and may allow for the recording of arterial blood pressure and heart rate when it would be difficult to achieve with a conventional system (e.g. during recovery from anesthesia).
Clinical relevance  The wireless invasive blood pressure monitor may allow continuous measurements when only intermittent measurements would be feasible with a wired system.