A core collection of common bean from the Iberian peninsula

Characterization of crop germplasm from specific regions helps understand the patterns of genetic variation that facilitates further germplasm collection, characterization, management and their more efficient utilization in genetics, breeding and other studies. Common bean (Phaseolus vulgaris L.) is a traditional crop in the Iberian Peninsula (Spain and Portugal) where subsistence farmers have been growing and maintaining their own cultivars since their introductions from the Americas in the sixteenth century. Our objectives were to: (i) characterize diversity in the landraces collected from the Iberian Peninsula and (ii) form a core collection. Of 388 landraces from the major production regions characterized for 34quantitative and 13 qualitative characters, including morphological, agronomic and biochemical traits, 74.7% had an Andean origin, 16.8% a Mesoamerican origin and 8.4% had seed mixtures or were recombinants between the two gene pools. Landraces of indeterminate climbing growth habit Type IV(47.2%) and bush determinate Type I(26.4%) with large (52.9%) and medium(27.4%) seeds of white (38.8%) and cream(25.9%) colour were predominant. Similarly, the ‘T’ phaseolin pattern and common bean race Nueva Granada were the most frequent(51%). Some exceptionally large-seeded landraces of Andean (e.g., PHA-0917 with119 g 100-seed weight^-1) and Mesoamerican (e.g., PHA-0399 with 66 g100-seed weight^-1) were found. These and other possible recombinants between the two gene pools merit further investigation. Fifty two landraces (13%) were chosen to form a core collection representing the genetic diversity in the Iberian Peninsula. This revised version was published online in July 2006 with corrections to the Cover Date.     

Interrelationships between cropping systems for pod and seed quality components and breeding implications in common bean

Breeding programmes in common bean (Phaseolus vulgaris L.) have mainly focused on performance under monoculture conditions. Interactions among cultivars and cropping systems do occur and genotypes bred for pure cropping may not be suitable for intercropping. This study was undertaken to obtain estimates of genetic parameters of quality traits for bush bean landraces grown in two cropping systems, and the interrelationships of these traits between pure cropping and intercropping with maize (Zea mays L.). Field experiments were conducted at two locations for two years. Expression of most traits was not strongly influenced by genotype × environment interactions. Heritability estimates were similar in both cropping systems for most pod and seed quality traits. Positive correlations were observed between pure cropping and intercropping for pod characters (weight, length, width and texture) and seed characters (dry and imbided weight, length, hardness, coat proportion, water absorption and crude protein). Use of a selection index is suggested for breeding for seed size, water absorption,coat proportion and crude protein for both cropping systems. However, larger gains would be expected in pure cropping for most traits. Bean accessions PHA-0267, PHA-0285, PHA-0286 and PHA-0299 should be used for developing acceptable culinary and high protein breeding lines for either cropping system. This revised version was published online in August 2006 with corrections to the Cover Date.     

Dynamics of pear-pathogenic Stemphylium vesicarium in necrotic plant residues in Dutch pear orchards

Brown spot disease on pear caused by Stemphylium vesicarium may affect leaves and fruits. Inoculum sources present on orchard floors play an important role in the epidemiology of pear brown spot. The pathogen can overwinter on plant residues and multiply and spread on the residues during the growing season. In the Netherlands, brown spot characteristically occurs only in a fraction of the orchards per season. Until now, no tools are available for Dutch pear growers to predict the risk of brown spot in specific orchards. As a consequence, preventive fungicide sprayings are common. The concentration of DNA of pear-pathogenic S. vesicarium was quantified by a specific TaqMan-PCR assay for various types of plant residues present on orchard floors to evaluate their importance as potential inoculum source. The pathogen was often found in residues of pear leaves, grasses and weeds, but only occasionally in mummies and prunings. Studies of the population dynamics showed that S. vesicarium decreased in dead pear leaves during early winter whereas pathogen populations developed with irregular pattern during the growing season on residues of weeds and grasses. Based on DNA concentrations of S. vesicarium in plant residue samples taken in 78 to 106 orchards in the springs of 2010, 2011 and 2012, the risk of brown spot development could be predicted for individual orchards. Such a risk prediction will allow growers to adapt their fungicide spray schedules to avoid unnecessary sprays in low-risk orchards.     

Enhancement of consolidated long-term memory by overexpression of protein kinase Mzeta in the neocortex

Memories are more easily disrupted than improved. Many agents can impair memories during encoding and consolidation. In contrast, the armamentarium of potential memory enhancers is so far rather modest. Moreover, the effect of the latter appears to be limited to enhancing new memories during encoding and the initial period of cellular consolidation, which can last from a few minutes to hours after learning. Here, we report that overexpression in the rat neocortex of the protein kinase C isozyme protein kinase Mζ (PKMζ) enhances long-term memory, whereas a dominant negative PKMζ disrupts memory, even long after memory has been formed.     

Swedish coffee (Astragalus boeticus L.), a neglected coffee substitute with a past and a potential future

Swedish coffee (Astragalus boeticus) seeds have been used as a coffee substitute, in particular during the nineteenth century and in times of scarcity. A. boeticus is found in the wild in a wide range of environments in the Mediterranean and Middle Eastern regions and is able to grow in areas with low and irregular rainfall. It is well-adapted to cultivated and disturbed environments, has indehiscent pods and high yield potential, and is therefore pre-adapted to cultivation and domestication. Swedish coffee is an annual that flowers in spring and produces small (3–6 mm × 3–5 mm) kidney-shaped seeds that can be harvested in summer. The genetic diversity of the species has not been studied, but evidence (wide range of environments, insect pollination) suggests that considerable diversity exists in the species. The genetic resources of Swedish coffee conserved in germplasm banks are very limited, with only 49 accessions conserved in six genebanks. Although no cultivated varieties exist at present and no breeding studies are underway, evidence suggests that limited breeding could result in considerable genetic advances. The cultivation of A. boeticus was very important during the nineteenth century in several countries of Europe, in particular in Sweden, where the cultivation was promoted as a coffee substitute by the monarchy. Several reports exist on its cultivation in several countries of Northern, Central and Southern Europe during the nineteenth century and beginning of the twentieth century. However, its cultivation gradually lost importance and was eventually abandoned. Swedish coffee can be grown in different types of soils as a regular winter or spring legume crop, and thanks to symbiosis with rhizobia may be able to perform well with reduced N fertilization. Several historical accounts report an excellent quality of the coffee substitute prepared with roasted Swedish coffee seeds. However, no investigations have been carried out to study the process of roasting and its influence on the final quality. The information presented here indicates that limited efforts in A. boeticus breeding, cultivation, and industrial processing potentially might result in the recovery of this neglected coffee substitute.     

萤光假单胞菌根部定殖对水培系统中香石竹生长的影响

 用筛选的萤光假单胞细菌(fluorescent Pseudomonas spp.)菌株WCS X.13,WCS417和WCS 358处理栽培于水培系统中不同香石竹栽培品种的根部,试验结果表明,在通气的三角烧瓶培养中,香石竹品种Pallas经WCS X.13菌株处理后根长、根重显著高于对照,植株鲜重相对增长率高于对照40%;经WCS417菌株处理根长高于对照,香石竹品种Lena经WCS 417菌株处理植株鲜重相对增长率高于对照32%,在营养膜培养中,在人工接种病原菌Fusarium oxysporum f.sp.dianthi的条件下,中抗品种Pallas经试验菌株处理根部6周以后,植株(根上部)鲜重均高于对照,表现促进植株生长的趋势。     

Oxytocin selectively gates fear responses through distinct outputs from the central amygdala

Central amygdala (CeA) projections to hypothalamic and brain stem nuclei regulate the behavioral and physiological expression of fear, but it is unknown whether these different aspects of the fear response can be separately regulated by the CeA. We combined fluorescent retrograde tracing of CeA projections to nuclei that modulate fear-related freezing or cardiovascular responses with in vitro electrophysiological recordings and with in vivo monitoring of related behavioral and physiological parameters. CeA projections emerged from separate neuronal populations with different electrophysiological characteristics and different response properties to oxytocin. In vivo, oxytocin decreased freezing responses in fear-conditioned rats without affecting the cardiovascular response. Thus, neuropeptidergic signaling can modulate the CeA outputs through separate neuronal circuits and thereby individually steer the various aspects of the fear response.