Fixed location hydroacoustic monitoring of fish populations in the tidal River Hull, north-east England, in relation to water quality

Abstract  Fixed location hydroacoustic fish monitoring was carried out at a series of sites in the tidal River Hull, north-east England, in July 1996 during periods of moderate freshwater flows and spring tides. This was followed by a corresponding series during a period of lower freshwater flows and spring tides in autumn 1996. The surveys indicated substantial numbers of fish living upstream and downstream of a depleted oxygen zone which exists in the tidal Hull. Conditions in this zone of poor water quality deteriorated further during low flow periods due to reduced dilution of effluents. Fish populations moved with the tide apparently in response to gradients of dissolved oxygen and salinity. Under conditions of low freshwater flow and high tides, gradients of salinity and oxygen were steeper and fish responses appeared more marked: at higher salinities, the response to increasing salinity overrode the response to decreasing oxygen availability.     

Modeling spatial variability in the life-cycle costs of low-volume forest roads

Cost estimation is probably the most decisive factor in the process of computer-aided, preliminary planning for low-volume road networks. However, the cost of construction is normally assumed to be route-independent for a specific project area, resulting in sub-optimal layouts. This is especially true for mountainous terrain and in areas with unstable subsoil. Here, we present a model for more accurately estimating spatial variability in road life-cycle costs, based on terrain surface properties as well as geological properties of the subsoil. This parametric model incorporates four structural components: embankment, retaining structures, pavement, and drainage and stream-crossing structures. It is linked to a geo-database that allows users to derive location-specific parameter values as input. In applying this model, we have demonstrated that variability in costs ranges widely for mountainous areas, with the most expensive construction being approximately five times greater there than on more favorable sites. This variability strongly affects the optimal layout of a road network. First, when location-specific slope gradients are considered, costs are reduced by about 17% from those calculated via currently available engineering practices; when both slope gradient and geotechnical formations are included, those costs are decreased by about 20%. Second, the length of the road network is increased by about 4% and 10% respectively, compared with current practices.     

Linkage Between the Incompatibility Locus Z and a β-Glucosidase Locus in Rye

Crosses of plants from the same I_0.1 line can be used for studying linkage relations between incompatibility loci and marker genes. Only one of the two incompatibility loci of rye has so far been localized, on chromosome 1R. In order to locate the second locus, crosses were performed with plants possessing known isozyme markers of the rye genome. Linkage was found with the β-glucosidase locus on chromosome 2R. By combined analysis a recombination value of C.144 was determined.     

Chromosomal location of fertility restoring genes for ‘wild abortive’ cytoplasmic male sterility using primary trisomics in rice

Summary Identification and location of fertility restoring genes facilitates their deployment in a hybrid breeding program involving cytoplasmic male sterility (CMS) system. The study aimed to locate fertility restorer genes of CMSWA system on specific chromosomes of rice using primary trisomics of IR36 (restorer), CMS (IR58025A) and maintainer (IR58025B) lines. Primary trisomic series (Triplo 1 to 12) was crossed as maternal parent with the maintainer line IR58025B. The selected trisomic and disomic F₁ plants were testcrossed as male parents with the CMS line IR58025A. Plants in testcross families derived from disomic F₁ plants (Group I crosses) were all diploid; however, in the testcross families derived from trisomic F₁ plants (Group II crosses), some trisomic plants were observed. Diploid plants in all testcross families were analyzed for pollen fertility using 1% IKI stain. All testeross families from Group I crosses segregated in the ratio of 2 fertile: 1 partially fertile+partially sterile: 1 sterile plants indicating that fertility restoration was controlled by two independent dominant genes: one of the genes was stronger than the other. Testcross families from Group II crosses segregated in 2 fertile: 1 partially fertile+ partially sterile: 1 sterile plants in crosses involving Triplo 1, 4, 5, 6, 8, 9, 11 and 12, but families involving triplo 7 and triplo 10 showed significantly higher X² values, indicating that the two fertility restorer genes were located on chromosome 7 and 10. Stronger restorer gene (Rf-WA-1) was located on chromosome 7 and weaker restorer gene (Rf-WA-2) was located on chromosome 10. These findings should facilitate tagging of these genes with molecular markers with the ultimate aim to practice marker-aided selection for fertility restoration ability.     

Use of multiparental inbred populations to determine allelic relationships of molecular markers

The assessment of polymorphism exhibited by molecular markers is an arduous but essential task that facilitates the use of molecular tools by breeders and geneticists. For that purpose, the value of a wheat composite population was assessed for characterizing the diversity of restriction fragment length polymorphism (RFLP) markers developed by INRA-Génoblé. The polymorphism of 13 genomic probes was measured over a set of 80 inbred lines randomly extracted by single-seed descent from a composite-cross of 16 wheat lines. The 13 probéenzyme combinations revealed 27 loci with codominant polymorphism. As many bands were so far unmapped, the segregational analysis of the progenies appeared very suitable for complex patterns, both in determining allelic relationships and in revealing linkage between loci. Allelic diversity, band sizes and chromosomal location assessed from nullisomic-tetrasomic lines are given for the 27 loci.     

Production of a Trisomic Series in Hordeum vulgare cv. 'Golden Promise' and its Use in Locating a Recessive Chlorina Gene

A trisomic series was produced from a triploid plant of barley (Hordeum vulgare L. cv. ‘Golden Promise’) derived from tissue culture. Its characteristics are briefly described and compared with two trisomic series reported previously. Trisomic number 1 performed poorly under glasshouse conditions. Number 2 failed to set any seed after selfing and must be maintained by pollinating with ‘Golden Promise’. The series was subsequently used to locate a recessive chlorina gene on barley chromosome 3.     

Chromosomal location of genes controlling grain size in a large grained selection of wheat (Triticum aestivum L.)

Summary Grain size in wheat is the most stable yield component and has a favorable effect on flour yield. To identify the chromosomes associated with the large grains of line G603-86, (grain weight over 60 mg and grain length of about 9 mm), F₃ lines, extracted from F₂ populations obtained from F₁ monosomics of crosses between G603-86 (P₁) and the monosomic set of Favorit (P₂) were tested in the field. ANOVA showed significant differences among parents for grain weight and grain length, but not for grain width or the factor expressing the difference in grain form and density. Homoeologous groups had significant effects on grain weight and on all components of grain weight, while genomes were not significantly different for any of these characters. Grain weight was significantly increased by chromosomes 6D and 4A of G603-86. Grain length was significantly increased by chromosomes 4A, 4B, 2B, 3A and 1B, grain width by chromosomes 1A and 1B, and the factor form-density by chromosomes 6D and 6A. The high grain size in G603-86 results from the effects of genes located on many chromosomes which affect grain dimensions, form and density.     

Nature orientation and opportunity: Who values and who has opportunity for satisfactory green spaces in proximity to their place of residence

Urban green spaces (UGS) provide important contributions to people. Yet, UGS planning requires better understanding of by whom and where such contributions are being valued or missed. Based on a mixed-methods online survey and choice experiment with residents of Wellington in Aotearoa New Zealand, we analyse how much and why residents value UGS and their benefits when deciding where to live and how socio-economic and spatial factors might impact nature orientation and opportunity for satisfactory local UGS. We find that local UGS are an important residential choice criteria for the majority of respondents, especially in the context of Wellington’s intensification plans. However, we show that socio-economic and spatial factors significantly impact whether someone values and is satisfied with UGS in proximity to their place of residence. Our findings call for careful scoping of a city’s population and spatial structure when planning for equitable UGS provision. More holistic approaches to green space planning are needed to address contextualities and the complex interdependencies between nature orientation and opportunity and to plan for green space distributions that provide opportunities now and help shaping nature orientation for future generations.     

Location of genes for chlorophyll synthesis on specific arms of chromosomes in Triticum aestivum

Summary An Indian hexaploid wheat var. Pb C591 has been shown to carry gene(s) for chlorophyll synthesis on chromosome 3A (Singh & Joshi, 1979). In the present study cv. Pb.C591, its monosomic 3A and diteocentrics for 3A, 3BL and 3DL of var. Chinese Spring have been used. The F₂ segregation involving crosses between Pb.C591 as male, monosomic line 3A of Pb.C591 (female) and ditelocentrics 3A, 3BL and 3DL of cv. Chinese Spring as male and female respectively has been observed. It has been found that there are two dominant genes regulating chlorophyll synthesis in cv. Chinese Spring. These genes are located on chromosomes arms 3A and 3DS respectively.These chlorophyll synthetic genes must be the same which were postulated by Sears (1956, 1957) as the normal alleles of virescent gene v ₂ (which was located on 3BS) on chromosomes 3A(v ₁) and 3D(V ₃).