Potential of twenty exotic germplasms to improve Brazilian maize architecture

Temperate and temperate x tropical germplasms were introduced into the maize breeding of the Department of Genetics (ESALQ-USP). Twenty populations designated as P-1 to P-20 and a check population were evaluated in a randomized complete block design with two replications at Piracicaba, SP, Brazil. Plots were 2.0 m long, spaced 1.0 m apart, with 10 plants per plot after thinning. The following traits were evaluated: PH, plant height; EH, ear height; TB, tassel branch number; KW, 100 kernels weight; EL, ear length; ED, ear diameter; KR, kernels per row, and RN, number of rows of kernels. The means of the exotic populations showed a variation in performance for all traits. The population means were greater than check means for KW, EL, and KR. Populations P-9, P-10, P-12, and P-13 showed low relative ear placement values (EH/PH index), indicating that these materials could contribute to lower ear placement in local populations. P-1 and P-9 showed a high potential to reduce TB. The phenotypic correlation coefficients among populations were positive for most combinations, except for RN with PH, EH, TB, and KW. Predictions of 19 composite means were obtained for all traits.

Influence of plant species and richness on pollutant removal in treatment wetlands

Les marais filtrants artificiels sont des écosystèmes recréés par l’homme dans le but d’optimiser l’épuration des eaux usées. Lors de la sélection d’espèces végétales pour la mise en place de ces marais filtrants, l’utilisation d’une polyculture ainsi que d’espèces indigènes non invasives est de plus en plus recommandée. Néanmoins, la plupart des marais filtrants existants sont des monocultures utilisant des plantes envahissantes, probablement à cause du manque d’évidences scientifiques sur les avantages de la diversité végétale et de la performance des espèces locales. Ainsi, les questions de recherche autour desquelles s’oriente ma thèse sont: Les polycultures présentent-elles un potentiel épuratoire aussi ou plus grand que les monocultures, et une espèce indigène est-elle aussi efficace et performante qu’une espèce exotique envahissante dans des marais filtrants ? Trois expériences ont été conduites afin de répondre à ces questions. J’ai d’abord testé l’influence de la richesse végétale sur l’élimination des polluants en deux dispositifs expérimentaux: 1) comparant deux espèces de plantes émergentes en monoculture ou combinées séquentiellement, et 2) évaluant la performance de quatre espèces flottantes plantées en monoculture par rapport à des associations de deux (avec toutes les combinaisons possibles) et de quatre espèces. Une troisième expérience a été réalisée afin de comparer l’efficacité épuratoire de l’haplotype européen envahissant du roseau commun (Phragmites australis) et de la sous-espèce locale non-invasive (P. australis subsp. americanus). La composition en espèces végétales a produit un effet notable sur la performance des marais filtrants. La comparaison des performances en mono- et en polyculture n’a pas permis de démontrer clairement les avantages de la diversité végétale pour l’élimination des polluants dans les marais filtrants. Toutefois, les marais filtrants plantés avec une combinaison d’espèces étaient aussi efficaces que les monocultures des espèces les plus performantes. La comparaison entre les deux sous-espèces de P. australis indiquent que la sous-espèce indigène pourrait remplacer le roseau exotique envahissant, évitant ainsi les potentiels risques environnementaux sans toutefois compromettre l’efficacité du traitement. Les résultats prometteurs de la sous-espèce indigène de P. australis doivent encore être testés dans des expériences à grande échelle avant d’utiliser largement cette espèce dans les marais filtrants. Nos résultats suggèrent que, dans des conditions où la performance des macrophytes disponibles est inconnue ou ne peut être déterminée, l’utilisation d’une combinaison d’espèces présente les meilleures chances d’accomplir le plus haut niveau possible d’élimination de polluants. De plus, même si la diversité végétale ne présente pas un avantage mesurable en termes d’efficacité épuratoire, celle-ci améliore la résilience des marais filtrants et leur résistance aux stress et aux maladies.

Effect of management strategies on the performance of ruminant livestock production systems and the safety of plant and animal products in the city of Sikasso, Mali

The regional population growth in West Africa, and especially its urban centers, will bring about new and critical challenges for urban development policy, especially in terms of ensuring food security and providing employment for the growing population. (Peri-) urban livestock and vegetable production systems, which can contribute significantly to these endeavours, are limited by various constraints, amongst them limited access to expensive production factors and their (in)efficient use. To achieve sustainable production systems with low consumer health risks, that can meet the urban increased demand, this doctoral thesis determined nutrient use efficiencies in representative (peri-) urban livestock production systems in three West African cities, and investigated potential health risks for consumers ensuing from there. The field study, which was conducted during July 2007 to December 2009, undertook a comparative analysis of (peri-) urban livestock production strategies across 210 livestock keeping households (HH) in the three West African cities of Kano/Nigeria (84 HH), Bobo Dioulasso/Burkina Faso (63 HH) and Sikasso/Mali (63 HH). These livestock enterprises were belonging to the following three farm types: commercial gardening plus field crops and livestock (cGCL; 88 HH), commercial livestock plus subsistence field cropping (cLsC; 109 HH) and commercial gardening plus semi-commercial livestock (cGscL; 13 HH) which had been classified in a preceding study; they represented the diversity of (peri-) urban livestock production systems in West Africa. In the study on the efficiency of ruminant livestock production, lactating cowsand sheep herd units were differentiated based on whether feed supplements were offered to the animals at the homestead (Go: grazing only; Gsf: mainly grazing plus some supplement feeding). Inflows and outflows of nutrients were quantified in these herds during 18 months, and the effects of seasonal variations in nutrient availability on animals’ productivity and reproductive performance was determined in Sikasso. To assess the safety of animal products and vegetables, contamination sources of irrigated lettuce and milk with microbiological contaminants, and of tomato and cabbage with pesticide residues in (peri-) urban agriculture systems of Bobo Dioulasso and Sikasso were characterized at three occasions in 2009. Samples of irrigation water, organic fertilizer and ix lettuce were collected in 6 gardens, and samples of cabbage and tomato in 12 gardens; raw and curdled milk were sampled in 6 dairy herds. Information on health risks for consumers of such foodstuffs was obtained from 11 health centers in Sikasso. In (peri-) urban livestock production systems, sheep and goats dominated (P<0.001) in Kano compared to Bobo Dioulasso and Sikasso, while cattle and poultry were more frequent (P<0.001) in Bobo Dioulasso and Sikasso than in Kano. Across cities, ruminant feeding relied on grazing and homestead supplementation with fresh grasses, crop residues, cereal brans and cotton seed cake; cereal grains and brans were the major ingredients of poultry feeds. There was little association of gardens and livestock; likewise field cropping and livestock were rarely integrated. No relation existed between the education of the HH head and the adoption of improved management practices (P>0.05), but the proportion of HH heads with a long-term experience in (peri-) urban agriculture was higher in Kano and in Bobo Dioulasso than in Sikasso (P<0.001). Cattle and sheep fetched highest market prices in Kano; unit prices for goats and chicken were highest in Sikasso. Animal inflow, outflow and dairy herd growth rates were significantly higher (P<0.05) in the Gsf than in the Go cattle herds. Maize bran and cottonseed expeller were the main feeds offered to Gsf cows as dry-season supplement, while Gsf sheep received maize bran, fresh grasses and cowpea pods. The short periodic transhumance of Go dairy cows help them maintaining their live weight, whereas Gsf cows lost weight during the dry season despite supplement feeding at a rate of 1506 g dry matter per cow and day, resulting in low productivity and reproductive performance. The daily live weight gains of calves and lambs, respectively, were low and not significantly different between the Go and the Gsf system. However, the average live weight gains of lambs were significantly higher in the dry season (P<0.05) than in the rainy season because of the high pressure of gastrointestinal parasites and of Trypanosoma sp. In consequence, 47% of the sheep leaving the Go and Gsf herds died due to diseases during the study period. Thermo-tolerant coliforms and Escherichia coli contamination levels of irrigation water significantly exceeded WHO recommendations for the unrestricted irrigation of vegetables consumed raw. Microbial contamination levels of lettuce at the farm gate and the market place in Bobo Dioulasso and at the farm gate in Sikasso were higher than at the market place in Sikasso (P<0.05). Pesticide residues were detected in only one cabbage and one tomato sample and were below the maximum residue limit for consumption. Counts of thermo-tolerant coliforms and Escherichia coli were higher in curdled than in raw milk (P<0.05). From 2006 to x 2009, cases of diarrhea/vomiting and typhoid fever had increased by 11% and 48%, respectively, in Sikasso. For ensuring economically successful and ecologically viable (peri-) urban livestock husbandry and food safety of (peri-) urban foodstuffs of animal and plant origin, the dissemination and adoption of improved feeding practices, livestock healthcare and dung management are key. In addition, measures fostering the safety of animal products and vegetables including the appropriate use of wastewater in (peri-) urban agriculture, restriction to approve vegetable pesticides and the respect of their latency periods, and passing and enforcement of safety laws is required. Finally, the incorporation of environmentally sound (peri-) urban agriculture in urban planning by policy makers, public and private extension agencies and the urban farmers themselves is of utmost importance. To enable an efficient (peri-) urban livestock production in the future, research should concentrate on cost-effective feeding systems that allow meeting the animals’ requirement for production and reproduction. Thereby focus should be laid on the use of crop-residues and leguminous forages. The improvement of the milk production potential through crossbreeding of local cattle breeds with exotic breeds known for their high milk yield might be an accompanying option, but it needs careful supervision to prevent the loss of the local trypanotolerant purebreds.

The role of exotic plants in the invasion of Seychelles by the polyphagous insect Aleurodicus disperses: a phylogenetically controlled analysis

The accidental introduction of the spiralling whitefly, Aleurodicus dispersus Russell (Homoptera: Aleyrodidae) to Seychelles in late 2003 is exploited during early 2005 to study interactions between A. dispersus, native and exotic host plants and their associated arthropod fauna. The numbers of A. dispersus egg spirals and pupae, predator and herbivore taxa were recorded for eight related native/exotic pairs of host plants found on Mahe, the largest island in Seychelles. Our data revealed no significant difference in herbivore density (excluding A. dispersus) between related native and exotic plants, which suggests that the exotic plants do not benefit from 'enemy release'. There were also no differences in predator density, or combined species richness between native and exotic plants. Together these data suggest that 'biotic resistance' to invasion is also unlikely. Despite the apparent lack of differences in community structure significantly fewer A. dispersus egg spirals and pupae were found on the native plants than on the exotic plants. Additional data on A. dispersus density were collected on Cousin Island, a managed nature reserve in which exotic plants are carefully controlled. Significantly higher densities of A. dispersus were observed on Mahe, where exotic plants are abundant, than on Cousin. These data suggest that the rapid invasion of Seychelles by A. dispersus may largely be due to the high proportion of plant species that are both exotic and hosts of A. dispersus; no support was found for either the 'enemy release' or the 'biotic resistance' hypotheses.

Optimization of a method for determination of phenolic acids in exotic fruits by capillary electrophoresis

In this work, the separation of nine phenolic acids (benzoic, caffeic, chlorogenic, p-coumaric, ferulic, gallic, protocatechuic, syringic, and vanillic acid) was approached by a 32 factorial design in electrolytes consisting of sodium tetraborate buffer(STB) in the concentration range of 10-50 mmol L(-1) and methanol in the volume percentage of 5-20%. Derringer`s desirability functions combined globally were tested as response functions. An optimal electrolyte composed by 50 mmol L(-1) tetraborate buffer at pH 9.2, and 7.5% (v/v) methanol allowed baseline resolution of all phenolic acids under investigation in less than 15 min. In order to promote sample clean up, to preconcentrate the phenolic fraction and to release esterified phenolic acids from the fruit matrix, elaborate liquid-liquid extraction procedures followed by alkaline hydrolysis were performed. The proposed methodology was fully validated (linearity from 10.0 to 100 mu g mL(-1), R(2) > 0.999: LOD and LOQ from 1.32 to 3.80 mu g mL(-1) and from 4.01 to 11.5 mu g mL(-1), respectively; intra-day precision better than 2.8% CV for migration time and 5.4% CV for peak area; inter-day precision better than 4.8% CV for migration time and 4.8-11% CV for peak area: recoveries from 81% to 115%) and applied successfully to the evaluation of phenolic contents of abiu-roxo (Chrysophyllum caimito), wild mulberry growing in Brazil (Morus nigra L.) and tree tomato (Cyphomandra betacea). Values in the range of 1.50-47.3 mu g g(-1) were found, with smaller amounts occurring as free phenolic acids. (C) 2009 Elsevier B.V. All rights reserved.

Influence of Apis mellifera L. (Hymenoptera: Apidae) on the Use of the Most Abundant and Attractive Floral Resources in a Plant Community

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Aquatic plant community in porto primavera reservoir

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of removal of a non-native tree species Mimosa caesalpiniifolia Benth. on the regenerating plant communities in a tropical semideciduous forest under restoration in Brazil

Exotic species are used to trigger facilitation in restoration plantings, but this positive effect may not be permanent and these species may have negative effects later on. Since such species can provide a marketable product (firewood), their harvest may represent an advantageous strategy to achieve both ecological and economic benefits. In this study, we looked at the effect of removal of a non-native tree species (Mimosa caesalpiniifolia) on the understory of a semideciduous forest undergoing restoration. We assessed two 14-year-old plantation systems (modified taungya agroforestry system; and mixed plantation using commercial timber and firewood tree species) established at two sites with contrasting soil properties in São Paulo state, Brazil. The experimental design included randomized blocks with split plots. The natural regeneration of woody species (height ≥0.2 m) was compared between managed (all M. caesalpiniifolia trees removed) and unmanaged plots during the first year after the intervention. The removal of M. caesalpiniifolia increased species diversity but decreased stand basal area. Nevertheless, the basal area loss was recovered after 1 year. The management treatment affected tree species regeneration differently between species groups. The results of this study suggest that removal of M. caesalpiniifolia benefited the understory and possibly accelerated the succession process. Further monitoring studies are needed to evaluate the longer term effects on stand structure and composition. The lack of negative effects of tree removal on the natural regeneration indicates that such interventions can be recommended, especially considering the expectations of economic revenues from tree harvesting in restoration plantings.

Risk assessment for invasive exotic plants using multi-criteria risk models

Invasive exotic plants have altered natural ecosystems across much of North America. In the Midwest, the presence of invasive plants is increasing rapidly, causing changes in ecosystem patterns and processes. Early detection has become a key component in invasive plant management and in the detection of ecosystem change. Risk assessment through predictive modeling has been a useful resource for monitoring and assisting with treatment decisions for invasive plants. Predictive models were developed to assist with early detection of ten target invasive plants in the Great Lakes Network of the National Park Service and for garlic mustard throughout the Upper Peninsula of Michigan. These multi-criteria risk models utilize geographic information system (GIS) data to predict the areas at highest risk for three phases of invasion: introduction, establishment, and spread. An accuracy assessment of the models for the ten target plants in the Great Lakes Network showed an average overall accuracy of 86.3%. The model developed for garlic mustard in the Upper Peninsula resulted in an accuracy of 99.0%. Used as one of many resources, the risk maps created from the model outputs will assist with the detection of ecosystem change, the monitoring of plant invasions, and the management of invasive plants through prioritized control efforts.

Invasive plant species do not create more negative soil conditions for other plants than natives

Abstract A major task in ecology is to establish the degree of generality of ecological mechanisms. Here we present results from a multi-species experiment that tested whether a set of invasive species altered the soil conditions to the detriment of other species by releasing allelopathic compounds or inducing shifts in soil biota composition, and whether this effect was more pronounced relative to a set of closely related native species. We pre-cultivated soil with 23 exotic invasive, 19 related native and 6 related exotic garden species and used plain soil as a control. To separate allelopathy from effects on the soil biota, we sterilized half of the soil. Then, we compared the effect of soil pre-cultivation and sterilization on germination and growth of four native test species in two experiments. The general effect of soil sterilization was positive. The effect of soil pre-cultivation on test species performance was neutral to positive, and sterilization reduced this positive effect. This indicates general absence of allelopathic compounds and a shift toward a less antagonistic soil biota by cultivation species. In both experiments, pre-cultivation effects did not differ systematically between exotic invasive, exotic garden or native species. Our results do not support the hypothesis that invasive plants generally inhibit the growth of others by releasing allelopathic compounds or accumulating a detrimental soil biota.

Plant communities and soil chemistry of shrub-steppe and pine savannah grasslands in southern British Columbia, Canada

Habitat fragmentation alters the edges of remnant habitat patches. We examined changes in the plant community and soil in relation to distance from edge and edge type for shrub-steppe and pine savannah grasslands in southern British Columbia, Canada. Community composition showed significant nonlinear relationships with distance-to-edge more frequently at paved roads and fruit crops than at dirt roads or control sites (i.e., in the interior of grassland patches), with changes typically extending 25-30 m. More exotic species and fewer native species were found near edges, and edges showed decreased cryptogam cover and increased bare ground, especially near paved roads. The soil factors that best predicted compositional changes were soil pH and Cu/Mn at paved roads, soil pH and nitrogen at fruit crops, and soil resistance at dirt roads. Variation partitioning suggested that both direct (e.g., propagule pressure) and indirect (environmental change) factors mediated edge-related community changes, and provided evidence that nonlinear responses at developed edges were not due to natural gradients. Given the range of grassland patch sizes in this region (many patches 1-100 ha), the edge effects we observed represent a considerable loss of "core" habitat, which must be accounted for in conservation planning and site restoration.

Genome projects and gene pools: New germplasm for plant breeding?

Crop gene pools have adapted to and sustained the demands of agricultural systems for thousands of years. Yet, very little is known about their content, distribution, architecture, or circuitry. The presumably shallow elite gene pools often continue to yield genetic gains while the exotic pools remain mostly untapped, uncharacterized, and underutilized. The concept and content of a crop’s gene pools are being changed by advancements in plant science and technology. In the first generation of plant genomics, DNA markers have refined some perceptions of genetic variation by providing a glimpse of a primary source, DNA polymorphism. The markers have provided new and more powerful ways of assessing genetic relationships, diversity, and merit by infusing genetic information for the first time in many scenarios or in a more comprehensive manner for others. As a result, crop gene pools may be supplemented through more rapid and directed methods from a greater variety of sources. Previously limited by the barriers of sexual reproduction, the native gene pools will soon be complemented by another gene pool (transgenes) and perhaps by other native exotic gene pools through comparative analyses of plants’ biological repertoire. Plant genomics will be an important force of change for crop improvement. The plant science community and crop gene pools may be united and enriched as never before. Also, the genomes and gene pools, the products of evolution and crop domestication, will be reduced and subjected to the vagaries and potential divisiveness of intellectual property considerations. Let the gains begin.

Proceedings of session, host-specificity testing of exotic arthropod biological control agents : the biological basis for improvement in safety /

"August 2000"--Cover.

Altered fungal sensitivity to a plant antimicrobial peptide through over-expression of yeast cDNAs

A yeast cDNA expression library was screened to identify genes and cellular processes that influence fungal sensitivity to a plant antimicrobial peptide. A plasmid-based, GAL1 promoter-driven yeast cDNA expression library was introduced into a yeast genotype susceptible to the antimicrobial peptide MiAMP1 purified from Macadamia integrifolia. Following a screen of 20,000 cDNAs, three yeast cDNAs were identified that reproducibly provided transformants with galactose-dependent resistance to MiAMP1. These cDNAs encoded a protein of unknown function, a component (VMA11) of the vacuolar H+-ATPase and a component (cytochrome c oxidase subunit VIa) of the mitochondrial electron transport chain, respectively. To identify genes that increased sensitivity to MiAMP1, the yeast cDNA expression library was introduced into a yeast mutant with increased resistance to MiAMP1. From 11,000 cDNAs screened, two cDNA clones corresponding to a ser/thr kinase and a ser/thr phosphatase reproducibly increased MiAMP1 susceptibility in the mutant in a galactose-dependent manner. Deletion mutants were available for three of the five genes identified but showed no change in their sensitivity to MiAMP1, indicating that these genes could not be detected by screening of yeast deletion mutant libraries. Yeast cDNA expression library screening therefore provides an alternative approach to gene deletion libraries to identify genes that can influence the sensitivity of fungi to plant antimicrobial peptides.