Estimation of natural outcrossing rate and genetic diversity in Lima bean (<Emphasis Type="Italic">Phaseolus lunatus</Emphasis> L. var. <Emphasis Type="Italic">lunatus</Emphasis>) from Brazil using SSR markers: implications for conservation and breeding

Lima bean (Phaseolus lunatus L.) is an important food source in Brazil, especially in the northeast region, where its production and consumption are high. The goals of the present study were to estimate natural outcrossing rates and genetic diversity levels of Lima bean from Brazil, using ten microsatellite loci to obtain information for their conservation and breeding. Fourteen accessions were selected from an experiment in field with open-pollinated and with the presence of pollinating insects. Twelve seeds of each of the 14 selected accessions were grown in screenhouse for tissue harvest and DNA extraction. The multilocus model was used to determine the reproductive system. The outcrossing rate was 38.1 % (t_m = 0.381; t_s = 0.078), and the results indicated a mixed mating system with a predominance of selfing (1 ? t_m = 61.9 %). The biparental inbreeding rate was high (t _m  ? t _s  = 0.303) and the multilocus correlated paternity was quite high (r _p(m) = 0.889), indicating that the progeny was mostly composed of full sibs. The average effective number of pollen donors per maternal plant (N _ep ) was low (1.12), and the fixation index for maternal genotypes (F _m ) was 0.945, indicating that most genitors resulted from inbreeding. The studied families presented considerable genetic variability: A = 6.10;  %P = 30; H _e  = 0.60 and H _o  = 0.077. Total diversity was high (H _T = 0.596), and a portion was distributed within families (H _S = 0.058). In addition, diversity was higher between families (D _ST = 0.538), and genetic differentiation was high (G _ST = 0.902). The results presented here can be used in the implementation of Lima bean conservation and breeding programs in Brazil.     

Influence of EDTA and citric acid on lead-induced oxidative stress to Vicia faba roots

Purpose

In spite of substantial advancement in recent past, the role of metal speciation in assessing biogeochemical behaviour of Pb is still topical. Organic ligands are capable to modify Pb speciation in nutrient/soil solution and in turn its soil–plant transfer and toxicity. In this sense, the main objective of this study was to evaluate the effect of organic ligands on Pb-induced oxidative stress to Vicia faba roots.

Materials and methods

V. faba seedlings grown to controlled hydroponic system were treated with 5 μM Pb as lead nitrate in the presence and absence of organic ligands viz ethylenediaminetetraacetic acid (EDTA) and citric acid (CA) for 1, 4, 8, 12, and 24 h. The chemical speciation of Pb (percent free and chelated Pb) in nutrient solution in the presence and absence of organic ligands was calculated using Visual Minteq speciation model. The effect of chemical speciation on Pb-induced oxidative stress to V. faba roots was investigated using plant enzymatic antioxidative system [superoxide dismutases (SOD), guaiacol peroxidise (GPX), ascorbate peroxidase (APX), glutathione reductase (GR), and catalase (CAT)]. The antioxidant enzymes activities were determined using ultraviolet spectrophotometer.

Results and discussion

The activities of SOD, GPX, APX, and GR significantly increased whereas that of CAT decreased in V. faba roots under Pb alone treatment. Lead-induced increase/decrease in antioxidant enzymes activities was not linear but varies with treatment exposure time. EDTA dose dependently inhibited Pb-induced changes in antioxidant enzymes activities. However, CA did not cause any significant change in Pb-induced variation in antioxidant enzymes activities, but delayed or slightly reduced the Pb effect.

Conclusions

The present study suggested that physiological responses of V. faba roots to Pb toxicity vary with applied Pb form and duration of exposure. EDTA can inhibit Pb-induced toxicity to V. faba seedlings by forming stable Pb-EDTA complexes due to its high binding strength for Pb. However, CA had no effect on Pb-induced toxicity to V. faba roots due to weak complexation with Pb.     

Landscape-scale modelling of agroforestry ecosystems services in Swiss orchards: a methodological approach

Context

Agroforestry systems in temperate Europe are known to provide both, provisioning and regulating ecosystem services (ES). Yet, it is poorly understood how these systems affect ES provision at a landscape scale in contrast to agricultural practises.

Objectives

This study aimed at developing a novel, spatially explicit model to assess and quantify bundles of provisioning and regulating ES provided by landscapes with and without agroforestry systems and to test the hypothesis that agroforestry landscapes provide higher amounts of regulating ES than landscapes dominated by monocropping.

Methods

Focussing on ES that are relevant for agroforestry and agricultural practices, we selected six provisioning and regulating ES—“biomass production”, “groundwater recharge”, “nutrient retention”, “soil preservation”, “carbon storage”, “habitat and gene pool protection”. Algorithms for quantifying these services were identified, tested, adapted, and applied in a traditional cherry orchard landscape in Switzerland, as a case study. Eight landscape test sites of 1 km?×?1 km, four dominated by agroforestry and four dominated by agriculture, were mapped and used as baseline for the model.

Results

We found that the provisioning ES, namely the annual biomass yield, was higher in landscape test sites with agriculture, while the regulating ES were better represented in landscape test sites with agroforestry. The differences were found to be statistically significant for the indicators annual biomass yield, groundwater recharge rate, nitrate leaching, annual carbon sequestration, flowering resources, and share of semi-natural habitats.

Conclusions

This approach provides an example for spatially explicit quantification of provisioning and regulating ES and is suitable for comparing different land use scenarii at landscape scale.

     

The use of multivariate analysis to characterize carcass and meat quality of goat kids protected by the PGI “Cabrito de Barroso”

Fifty five suckling kids from three genotypes and two sexes protected by the PGI “Cabrito de Barroso” European quality label were used in this experiment. Carcass quality was assessed using indices from carcass measurements, dressing percentages, refrigerated losses, higher priced joints proportion and tissue composition of the carcass. Meat pH, colour, total pigment, fat, dry matter, collagen determinations (total and soluble), cooking losses and shear force estimated in longissimus thoracis et lumborum (LTL) and gluteobiceps (GB) muscles were used to characterize meat quality. Principal component (PC) analysis was performed in order to examine carcass quality traits (n = 16) and meat quality (n = 16) traits. The five first principal components (PCs) explained about 86% of the total variability for carcass quality and 75% of the total variability for meat quality. Compactness indices of carcass and leg, carcass weight and subcutaneous fat were the most effective variables for the PC1, whereas the higher priced joints proportion, muscle proportions of the higher priced joints and of the carcass and the muscle and bone ratio were useful to define the PC2. The first PC of the meat quality parameters was characterized by colour traits (L, b, a, C, H and total pigment) whereas collagen determinations (total collagen and collagen solubility) defined the second PC. When the carcass quality data were projected on the plane defined by the first two PCs, two separate groups of points appeared, corresponding to the animals with slaughter live weight higher or lower than 10 kg. The distribution of the meat quality data on the plane defined by the first two PCs allowed the identification of two separate groups, corresponding to the muscles GB and LTL. The differences between genotypes tend to be small and related to slaughter live weight, which implies certain constancy in carcass and meat quality of the PGI “Cabrito de Barroso”.     

Detection of <Emphasis Type="Italic">Trypanosoma vivax</Emphasis> DNA in semen from experimentally infected goats

The present work aimed to investigate the presence of T. vivax DNA in the semen of experimentally infected goats. Twelve male goats native to the Brazilian Northeast, adults, were randomly assigned to two experimental groups: the infected group consisting of six goats infected intravenously with 0.5 mL of blood containing approximately 1.25?×?10⁵ trypomastigotes of T. vivax, and a control group composed of six uninfected goats. After the infection, clinical examinations aiming to evaluate rectal temperature, parasitemia and hematocrit were performed. Semen samples were collected from goats by electroejaculation on the 7th, 14th and 21st days post-infection (dpi). The recombinant DNA-encoding gene encoding the L-like-specific gene for T. vivax. The infection was characterized by increased rectal temperature, high parasitemia and significant reduction of hematocrit values. Results for T. vivax DNA detection using TviCatL-PCR were positive in all semen samples from the infected group collected on 7th, 14th and 21st dpi. The presence of T. vivax DNA in 7th dpi suggests the early invasion of the parasite in the reproductive organs. Also, the finding of T. vivax DNA in all periods analyzed may suggest the continued elimination of the parasite in the semen, which may increase the chances of sexual transmission. Thus, T. vivax DNA is recorded for the first time in the semen of infected goats. Thus, these data are of great importance, since the detection of the T. vivax genetic material in the semen may point to the possibility that the parasite may be transmitted through the sexual pathway.