Effect of local stand density on reproductive processes of the sub-boreal conifer Picea jezoensis Carr. (Pinaceae)

The effect of local pollen donor density (conspecific) and local total tree density (all species) on pollen pool diversity, outcrossing rate, and filled seed ratio were examined in a natural stand of the sub-boreal conifer Picea jezoensis Carr. Seed cones were collected from 17 mother trees, and the percentage of filled seed were calculated for five cones per tree. In addition, local stand density of pollen donors and total trees were investigated within r<30 m from the focal mother trees. Using four polymorphic microsatellite markers, the average pairwise kinship coefficient F_S and multilocus outcrossing rate t_m were estimated on germinated seedlings sampled from 14 mother trees. F_S showed significant positive correlation to local total tree density (r=0.541, p=0.046). Since F_S is inversely proportional to the effective number of pollen donors N_ep, genetic diversity of pollen pool was decreased in mother trees with higher local total tree density. Applying a generalized linear mixed model to filled seed ratio and local stand density of pollen donors and total trees, a negative impact of local pollen donors on filled seed ratio was found. We conclude that both local stand density as well as global stand density are important in the management of a natural stand of P. jezoensis.     

Rice Metabolomics

Metabolomics is a recently developed technology for comprehensive analysis of metabolites in organisms. Plant metabolites that are produced for the growth, development, and chemical defense of plants against climatic alterations or natural predators are also useful to us as nutrients or medicines; hence, it is important to comprehend the amounts and varieties of plant metabolites. Besides providing an understanding of the metabolic state in plants under various circumstances, metabolomic techniques are applicable to the clarification of the functions of unknown genes by using natural variants or mutants of the target plants. Furthermore, a metabolomic approach might be useful in the breeding of crops, since valuable plant traits such as taste and yield are closely related to metabolic conditions. Here, we describe the methodology of metabolomics including sample extraction and preparation, metabolite detection, and data processing and analysis, and introduce the application of metabolomic studies to rice.     

Reduction of nitrogen,phosphorus, and suspended solids effluent loads from paddy fields by transplanting into retained ponding water using a GNSS-controlled rice transplanter

Paddy and Water Environment - We measured nutrient inflows and outflows on reclaimed land (157&nbsp;km2, including 100&nbsp;km2 of paddy fields) in Lake Hachiro. The net effluent loads...     

Both environmental factors and countermeasures affect wild boar damage to rice paddies in Boso Peninsula, Japan

Populations of wild boar (Sus scrofa Linnaeus, 1758) and reports of crop damage by them have increased in Japan. In considering strategies for damage control, it is necessary to quantify both the environmental factors and the countermeasures affecting damage. We surveyed damage by wild boar in 1540 rice paddies on the Boso Peninsula. We obtained environmental factors by GIS: distance from forest edges, rivers and settlements; overground openness; and human population density. We recorded the weeding and fencing practices as countermeasures. We constructed cumulative logit models using Bayesian inference to predict damage and assessed the importance of the simultaneous evaluation of environmental factors and countermeasures by deviance information criteria. The best model incorporated both environmental factors and countermeasures, indicating that both are important for predicting damage. It showed that weeding around rice paddies, electric fencing and corrugated iron fencing were effective at reducing damage by wild boar. The risk of damage increased with lower values of distance from forest edges and rivers, overground openness, and human population density, and with higher values of distance from roads. These environmental factors allowed us to identify high-risk cropland where countermeasures could be introduced to reduce damage.     

Nested PCR‐RFLP is a high‐speed method to detect fungicide‐resistant Botrytis cinerea at an early growth stage of grapes

BACKGROUND: Grey mould caused by the fungus Botrytis cinerea Pers. ex Fr. is one of the major diseases in grapes. The use of fungicides is a simple strategy to protect grapes against B. cinerea disease. However, phenotypes exhibiting resistance to fungicides have been detected in B. cinerea populations. The variation of fungicide‐resistant B. cinerea isolates renders B. cinerea disease control difficult in grapevine fields. RESULTS: The authors have developed a nested polymerase chain reaction–restriction fragment length polymorphism (PCR‐RFLP) method to detect fungicide‐resistant B. cinerea isolates at an early growth stage of grapes in grapevine fields. The nested PCR‐RFLP method was carried out to detect benzimidazole‐, phenylcarbamate‐ and/or dicarboximide‐resistant B. cinerea isolates from grape berries and leaves at Eichorn–Lorenz growth stage 25 to 29. This method successfully detected fungicide‐resistant B. cinerea isolates at an early growth stage of grapes. In addition, only 8 h was required from tissue sampling to phenotyping of fungicide resistance of the isolates. CONCLUSION: It is proposed that the early diagnosis of fungicide‐resistant B. cinerea isolates would contribute to further improvement of integrated pest management against B. cinerea in grapevine fields, and that the nested PCR‐RFLP method is a high‐speed, sensitive and reliable tool for this purpose. Copyright © 2008 Society of Chemical Industry     

Occurrence of bacterial black shoot disease of European pear in Yamagata Prefecture

Black lesions on shoots of European pear trees observed in an orchard in Yamagata Prefecture in May 2007 were suspected to be caused by a bacterial pathogen. The surface of the colonies isolated on a high sucrose medium did not have the crater morphology that is characteristic of E. amylovora bvs. 1–3, and a specific DNA fragment was amplified from the isolates in the PCR using the EprpoD primer set. The partial sequences of the 16S rRNA gene placed the isolates in the genus Erwinia. The isolates differed serologically from E. amylovora biovars and E. pyrifoliae in an Ouchterlony double-diffusion test although their bacterial properties suggested that they are closely related to E. amylovora biovars and E. pyrifoliae. In a DNA–DNA hybridization test, the relatedness between the isolates and E. amylovora biovars or E. pyrifoliae did not exceed 70% level, indicating that they are independent species. Thus, the isolates belongs to the genus Erwnia but are not E. amylovra or E. pyrifoliae. After succulent pear shoots were injected with bacterial suspensions (10⁹, 10⁸, 10⁷ and 10⁶ cfu/ml) of the isolates, lesions formed with 10⁹ and 10⁸ cfu/ml, but the disease incidence with 10⁸ cfu/ml was much lower than with E. amylovora and E. pyrifoliae. Virulence of the present isolates is thus thought to be very weak. On the basis of these results, we consider that this is a new shoot disease of European pear. In the 2007 season, all affected trees were pulled out after harvest. No symptoms have been observed in field surveys since the fruitlet season in 2007.     

Weed competitiveness of the lowland rice varieties of NERICA in the southern Guinea Savanna

Weed competition is a major constraint to lowland rice production in West Africa. Interspecific rice varieties named New Rice for Africa (NERICA) may have superior weed competitiveness and could as such play an important role in integrated weed management. The NERICA varieties were developed from the wide cross between high-yielding Oryza sativa (L.) and weed competitive and disease resilient Oryza glaberrima (Steud.). In this study weed competitiveness of all 60 lowland varieties of NERICA (NERICA-L) was compared with their most frequently used parents [IR64 (O. sativa) and TOG5681 (O. glaberrima)], the weed competitive variety Jaya (O. sativa) and the O. glaberrima upland NERICA parent CG14. During the 2006 and 2007 rainy seasons these varieties were grown under weed-free and weedy conditions in a lowland farmers’ field with partially controlled irrigation in south-east Benin. Weedy plots included single hand weeding at 28 days after sowing, whereas weed-free plots were weekly weeded.     

Hematological and splenic Doppler ultrasonographic changes in dogs sedated with acepromazine or xylazine

Objective

To evaluate the onset and duration of hematological changes and the use of Doppler ultrasound (spleen) in dogs sedated with acepromazine or xylazine.

Genetic relationships among sympatric varieties of <Emphasis Type="Italic">Acer mono</Emphasis> in the Chichibu Mountains and Central Hokkaido,Japan

Acer mono Maxim. is one of the major components of cool temperate forests in Japan. Some of its many varieties are distributed sympatrically. Because of its great variability, the intraspecific taxonomy and nomenclature of the species are controversial. To understand the genetic relationships among these varieties and whether hybridization or introgression occurred among the sympatric varieties, we studied the genetic relationships among sympatric varieties of A. mono in the Chichibu Mountains (A. mono var. ambiguum, A. mono var. connivens, A. mono var. marmoratum) and Central Hokkaido (A. mono var. mayrii and A. mono var. glabrum) in Japan. Our results showed that varieties in Chichibu are genetically close, suggesting that hybridization or introgression might occur between these varieties, which could explain the higher genetic diversity of varieties in Chichibu than in Hokkaido. In contrast to the close relationships between the varieties in Chichibu, varieties in Hokkaido seemed relatively separated from each other; indeed, there may be reproductive isolation between the two varieties. The results provide new insight for the taxonomy of the varieties of A. mono, especially the sympatric varieties, in Japan.