40 research outputs found
Housing: An Analysis of Ownership and Investment Based on the Household Savings Survey
In 2001, Statistics New Zealand conducted a major survey of the assets and liabilities of New Zealanders called the Household Savings Survey (HSS). This paper presents the results of an analysis of ownership and investment in housing based on the results of that survey. International comparisons suggest that the rates of home ownership, investment in property and housing debt levels in New Zealand are broadly comparable with those in Australia and the United States and with a wider set of countries. An exception is that younger age groups in New Zealand hold more investment property than their counterparts in the USA and Australia. In New Zealand almost one in ten couples owned rental property in 2001, while one in five owned some form of investment property. We examine the factors that govern tenure choice and gearing. Of note is the fact that 44% of couples and 56% of individual home owners have debt free residential properties. Households' balance sheets reflect the importance of housing for both assets and liabilities. We complement the analysis of the cross-sectional unit record data from the HSS with an analysis of housing taken from the households' aggregate balance sheets from 1978 to 2004 from the Reserve Bank of New Zealand. We use these data to form a measure of household saving based on the stock of net equity. We then adjust this measure of savings for changes in house prices, and find that this adjustment explains almost two thirds of the difference between the stock and flow measure of household savings, the latter taken from the Household Income and Outlay Accounts. Furthermore we find that from 1980 to 2005 the annual average rate of household saving based on these estimates from household balance sheets was 12.4% of personal disposable income, after removing the effect of changes in house price. Arguably this is a preferable measure of household saving to the widely cited negative rates of household saving based on national income accounts. We further use the balance sheet data to estimate the extent to which households have apparently withdrawn equity from their housing assets for investment in other forms or consumption. We find that on average a rise of one dollar in housing net equity is associated with 10 cents of apparent equity withdrawal.Housing; New Zealand; Portfolio; Wealth; Ownership; Equity; Gearing; Equity withdrawal; Measures of saving
Fungistatic activity mediated by volatile organic compounds is isolate-dependent in Trichoderma sp. “atroviride B”
Trichoderma spp. produce multiple bioactive volatile organic compounds (VOCs). While the bioactivity of VOCs from different Trichoderma species is well documented, information on intraspecific variation is limited. The fungistatic activity of VOCs emitted by 59 Trichoderma sp. “atroviride B” isolates against the pathogen Rhizoctonia solani was investigated. Eight isolates representing the two extremes of bioactivity against R. solani were also assessed against Alternaria radicina, Fusarium oxysporum f. sp. lycopersici and Sclerotinia sclerotiorum. VOCs profiles of these eight isolates were analyzed using gas chromatography–mass spectrometry (GC-MS) to identify a correlation between specific VOCs and bioactivity, and 11 VOCs were evaluated for bioactivity against the pathogens. Bioactivity against R. solani varied among the fifty-nine isolates, with five being strongly antagonistic. All eight selected isolates inhibited the growth of all four pathogens, with bioactivity being lowest against F. oxysporum f. sp. lycopersici. In total, 32 VOCs were detected, with individual isolates producing between 19 and 28 VOCs. There was a significant direct correlation between VOC number/quantity and bioactivity against R. solani. 6-pentyl-α-pyrone was the most abundant VOC produced, but 15 other VOCs were also correlated with bioactivity. All 11 VOCs tested inhibited R. solani growth, some by >50%. Some of the VOCs also inhibited the growth of the other pathogens by >50%. This study demonstrates significant intraspecific differences in VOC profiles and fungistatic activity supporting the existence of biological diversity within Trichoderma isolates from the same species, a factor in many cases ignored during the development of biological control agents
Evaluation of Genetic Diversity in White Clover (\u3cem\u3eTrifolium Repens\u3c/em\u3e L.) Through Measurement of Simple Sequence Repeat (SSR) Polymorphism
White clover (Trifolium repens L.) is a key important temperate pasture legume. Due to the obligate outbreeding nature of white clover, individual genotypes within cultivars are highly genetically heterogeneous. Genetic diversity has been assessed within and between 16 elite cultivars derived from Europe, North and South America, New Zealand and Australia
Genetic Analysis of the Interaction Between Perennial Ryegrass and the Fungal Endophyte \u3cem\u3eNeotyphodium Lolii\u3c/em\u3e
The fungal endophyte Neotyphodium lolii is widely distributed in perennial ryegrass pastures, especially in Australia and New Zealand. The presence of the endophyte is associated with improved tolerance to water and nutrient stress and resistance to insect pests, but is accompanied by reduced herbivore feeding. The molecular mechanisms responsible for these endophyte-related traits are in general poorly understood. Comparisons of different grass-endophyte associations show that endophyte-related traits are affected by both endophyte and host genotype, and environmental interactions
Application of Molecular Technologies in Forage Plant Breeding
Key points A range of molecular breeding technologies have been developed for forage plant species including both transgenic and non-transgenic methodologies. The application of these technologies has the potential to greatly increase the range of genetic variation that is available for incorporation into breeding programs and subsequent delivery to producers in the form of improved germplasm. Further developments in detailing the phenotypic effect of genes and alleles both through research in target species and through inference from results from model species will further refine the delivery of new forage cultivars
Genetic Variation in the Perennial Ryegrass Fungal Endophyte \u3cem\u3eNeotyphodium Lolii\u3c/em\u3e
The common fungal endophytes (Neotyphodium species) of temperate pasture grasses are associated with improved tolerance to water and nutrient stress and resistance to insect pests, but are also the causal agents of animal toxicoses. Considerable variation exists among grass-endophyte associations for these beneficial and detrimental agronomic traits. The extent to which this variation may be attributed to the endophyte genotype, the host genotype or environmental interactions is currently unknown. The development of molecular genetic markers for endophytes based on simple sequence repeat (SSR) loci and the demonstration of the specific detection of endophytes in planta with these markers (van Zijll de Jong et al., 2005) allows efficient assessment of endophyte diversity in grass populations
The NADPH Oxidases Nox1 and Nox2 Differentially Regulate Volatile Organic Compounds, Fungistatic Activity, Plant Growth Promotion and Nutrient Assimilation in Trichoderma atroviride
In eukaryotic systems, membrane-bound NADPH oxidases (Nox) generate reactive oxygen species (ROS) as a part of normal physiological functions. In the soil-borne mycoparasitic and plant facultative symbiont Trichoderma atroviride, Nox1 and the regulator NoxR are involved in differentiation induced by mechanical damage, while the role of Nox2 has not been determined. The knock-out strains Δnox1, ΔnoxR and Δnox2 were compared to the parental strain (WT) in their ability to grow and conidiate under a series of stress conditions (osmotic, oxidative, membrane, and cell-wall stresses). All three genes were differentially involved in the stress-response phenotypes. In addition, several interactive experiments with biotic factors (plant seedlings and other fungi) were performed comparing the mutant phenotypes with the WT, which was used as the reference strain. Δnox1 and ΔnoxR significantly reduced the antagonistic activity of T. atroviride against Rhizoctonia solani and Sclerotinia sclerotiorum in direct confrontation assays, but Δnox2 showed similar activity to the WT. The Δnox1, ΔnoxR, and Δnox2 mutants showed quantitative differences in the emission of several volatile organic compounds (VOCs). The effects of a blend of these volatiles on plant-growth promotion of Arabidopsis thaliana seedlings were determined in closed-chamber experiments. The increase in root and shoot biomass induced by T. atroviride VOCs was significantly lowered by ΔnoxR and Δnox1, but not by Δnox2. In terms of fungistatic activity at a distance, Δnox2 had a significant reduction in this trait against R. solani and S. sclerotiorum, while fungistasis was highly increased by ΔnoxR and Δnox1. Identification and quantification of individual VOCs in the blends emitted by the strains was performed by GC-MS and the patterns of variation observed for individual volatiles, such as 6-Pentyl-2H-pyran-2-one (6PP-1) and (E)-6-Pent-1-enylpyran-2-one (6PP-2) were consistent with their negative effects in plant-growth promotion and positive effects in fungistasis at a distance. Nox1 and NoxR appear to have a ubiquitous regulatory role of in a variety of developmental and interactive processes in T. atroviride either as positive or negative modulators. Nox2 may also have a role in regulating production of VOCs with fungistatic activity
The interplay between the effectiveness of the grass-endophyte mutualism and the genetic variability of the host plant
Neotyphodium endophytic fungi, the asexual state of Epichloë species, protect cool-season grasses against stresses. The outcomes of Neotyphodium-grass symbioses are agronomically relevant as they may affect the productivity of pastures. It has been suggested that the mutualism is characteristic of agronomic grasses and that differential rates of gene flow between both partners’ populations are expected to disrupt the specificity of the association and, thus, the mutualism in wild grasses. We propose that compatibility is necessary but not sufficient to explain the outcomes of Neotyphodium-grass symbiosis, and advance a model that links genetic compatibility, mutualism effectiveness, and endophyte transmission efficiency. For endophytes that reproduce clonally and depend on allogamous hosts for reproduction and dissemination, we propose that this symbiosis works as an integrated entity where gene flow promotes its fitness and evolution. Compatibility between the host plant and the fungal endophyte would be high in genetically close parents; however, mutualism effectiveness and transmission efficiency would be low in fitness depressed host plants. Increasing the genetic distance of mating parents would increase mutualism effectiveness and transmission efficiency. This tendency would be broken when the genetic distance between parents is high (out-breeding depression). Our model allows for testable hypotheses that would contribute to understand the coevolutionary origin and future of the endophyte-grass mutualism