Correlates of diet quality in the Quebec population

OBJECTIVE: To determine the correlates of a high-fat diet in urban, suburban and rural areas of Quebec, Canada. DESIGN: A secondary analysis of data collected as part of a 5-year multi-factorial, multi-setting, community-intervention project. SETTING: Urban, suburban and rural settings of the province of Quebec, 1997. SUBJECTS: Data were analysed from a sample of 5214 participants (2227 males, 2987 females). A food-frequency questionnaire was completed and a global index of food quality was calculated. Logistic regression was used to identify correlates of a diet high in total fats, saturated fat and cholesterol. RESULTS: In both genders, lower level of education, smoking status, French and English languages compared with other languages spoken at home, and a rural environment were associated with poor diet quality. Having no intention to eat low-fat dairy products more often was associated with a high-fat diet. In men, obesity (body mass index >/=30 kg m(-2)) and absence of reported health problems were correlates of a high-fat diet, while, in women, lower physical activity was a correlate. CONCLUSIONS: Future health interventions in Quebec should target people with low education, smokers and those living in a rural environment. Obese men and sedentary women should have access to specific dietetic resources.     

Spaced plant evaluation of Mediterranean germplasm collections of perennial ryegrass

Summary A sample of 50 wild populations of perennial ryegrass (12 from northern Italy and 38 from Corsica) was tested with controls as spaced plant nurseries in two locations in France. Multivariate analyses, such as principal component analysis, hierarchical clustering and factorial discriminant analysis were used to describe the genetic variability of such Mediterranean material.On the whole, Mediterranean populations do not appear to be more promosing than the north European varieties. However, some populations from Corsica could be used to develop genetic resources for the Mediterranean area.The interest of each cluster is discussed and geographical repartition of clusters is shown on country maps.The factorial discriminant analysis gives a linear discriminant Fisher function which clearely discriminates two groups of populations according to their country of origin.     

Stem and head reaction of winter wheat cultivars to artificial inoculation by Microdochium nivale under controlled environment and field conditions

Summary Experiments to assess variation in the resistance of winter wheat to infection by Microdochium nivale were conducted over two consecutive years. Resistance was evaluated using an agar disk technique to reproduce stem lesions and by spraying a conidial suspension to reproduce head blight symptoms. Significant variation for stem reaction measured as stem lesion area (SLA), and head reaction measured as disease severity (DS) was found in the 33 winter wheat genotypes tested. Data obtained over two years in controlled environment conditions were significantly correlated (r=0.713 for SLA and r=0.738 for DS), whereas field data showed a significant genotype x year interaction for disease severity. Quantitative variation for susceptibility to stem and head infection by M. nivale was found among the 33 genotypes tested. The majority of genotypes expressed moderate susceptibility, with cultivar Goupil being very susceptible to both stem and head infection, and the remainder, Renan, Arminda, Munstertaler and Saint-Johann were the most resistant. Resistance to stem and head to M. nivale were not correlated (r=0.358).     

IBD-based QTL detection in inbred pedigrees: A case study of cereal breeding programs

Mapping quantitative trait loci in plants is usually conducted using a population derived from a cross between two lines. The power of such QTL detection and mapping strategies and the estimation of the effects highly depend on the choice of the two parental lines. Thus, the QTL detected in such populations only represent a small part of the genetic architecture of the trait. Besides, the effects of only two alleles are characterized, which is of limited interest to the breeder. On the other hand, common pedigree breeding material remains unexploited for QTL mapping. From a pre-breeding perspective, the utilization of the good quality phenotypic data generated by breeders can be improved through the search and manipulation of QTL. The development of statistical techniques suitable for QTL mapping in general conventional breeding populations is thus challenging. In this study, we extend QTL mapping methodology to a generalized framework, based on a two-step IBD variance component approach, applicable to any type of breeding population coming from inbred parents. The proposed developments attempt to make full use of any inferable relatedness information between the parents. The power and accuracy of this method were assessed on simulated data mimicking conventional breeding programs in cereals, in an effort to reproduce actual conditions of marker and gene allelic frequencies across the parental lines. A wide range of breeding scenarios and of genetic architectures was explored. We demonstrated that taking into account the estimable relatedness between the parents significantly improved the power and accuracy of the QTL parameter estimations. This revised version was published online in July 2006 with corrections to the Cover Date.     

The detection of snail host habitats in liver fluke infected farms by use of plant indicators

Field investigations in 361 liver fluke infected cattle- or sheep-breeding farms on acid soil were carried out during thirty years in March and April to record indicator plants in relation to the category of site colonized by the intermediate host of liver fluke, the snail Galba truncatula. Seven types of snail zones and six species of indicator plants were recorded in the 7709 positive sites studied. The most frequent habitats were located at the peripheral extremities of open drainage furrows. Juncus acutiflorus, Juncus effusus, Glyceria fluitans, and Agrostis stolonifera were the indicator plants. Plant indicators were highly efficient (38-80% of variance explained) when used with the size of site area within a hydrographical zone. The identification of positive sites for G. truncatula is a key for controlling the intermediate host on pastures through biological control with predatory molluscs. The positive sites may be detected using a two-step method including first categorization of hydrographical zones and then, within a zone, use of one or several indicator plants (frequently J. acutiflorus).     

Isozyme polymorphism and geographic differentiation in a collection of French perennial ryegrass populations

Summary A sample of 60 natural populations of perennial ryegrass from France has been studied for allelic variation at 7 polymorphic enzyme loci. Population genetic statistics are of the same magnitude than those previously reported for other outbreeding, short-lived perennial species (P = 64%, A = 2.75, H = 0.270).Genotype frequencies at most collection sites do not deviate significantly from Hardy-Weinberg expectations, with however a slight deficit of heterozygotes which may be accounted for by a Wahlund effect. Gene diversity is mainly explained by the within population component. The between population differentiation F_st averaged on 4 loci is only 0.054, which accounts for only 6% of the whole diversity.When mapped, most allele frequencies do not show any special structure. Only five alleles present a clinal trend from North to South. These 5 alleles are probably related to some climatic factors such as average temperature or potential evapotranspiration. The causal hypotheses about the low level of between-population differentiation and spatial structure are discussed with reference to the literature.The consequences of the found population structure for sampling and conservation strategies of natural populations for genetic resources are presented and discussed.     

Cell neutrality in sodium chloride‐treated leaves and calli of the wilty mutant lycopersicon esculentum flacca and the wild species lycopersicon peruvianum

Some parameters involved in cell neutrality (inorganic solute, cation‐anion balance, proline and organic acid contents linked to oxidative respiration, and PEPCase activity) were determined in salinized plant leaves and leaf calli from two tomato species, the wilty mutant Lycopersicon esculentum cv flacca, and the wild relative L. peruvianum. Callus sensitivity was associated to membrane integrity and cell neutrality; while whole plant sensitivity was linked to nutritional unbalance and energy supply, both factors affecting the maintenance of the cell neutrality by means of ion translocation/compartimentalization.