Two studies examined the novel proposal that implicit theories of intelligence (C. S. Dweck & E. L. Leggett, 1988) moderate both the effects of performance trends on ability inferences and the perceived diagnosticity of temporal versus normative feedback. Results from 613 adolescents and 42 teachers confirmed that entity theorists perceived initial outcome as more diagnostic and inferred higher ability in another (Study 1) and in the self (Study 2) in a declining outcome condition; incremental theorists perceived last outcome as more diagnostic and inferred higher ability in an ascending condition. Experimental induction of beliefs about ability had similar effects. As predicted, self-appraisal was affected more by temporal feedback among incremental theorists and by normative feedback among entity theorists. Results help resolve prior mixed findings regarding order effects and responses to temporal and normative evaluation.

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Hieracium is an established model system for studying the cytological and genetic basis of gametophytic apomixis. In common with most known apomicts, the formation of 'maternal seed' is not exclusive in Hieracium, as apomixis operates in conjunction with a low level of sexuality. When this occurs the form of apomixis is described as 'facultative'. The formation of maternal seed in these plants is characterised by the avoidance of meiosis followed by the parthenogenetic development of an unreduced egg cell. In some ovules, however, meiosis does proceed, and sometimes the fertilisation of an egg cell presages embryogenesis. As a result, this mechanism of facultative apomixis leads to the formation of several different types of progeny, each representing a unique combination of meiosis/apomeiosis and fertilisation/parthenogenesis. Furthermore, fertilisation may involve either self or non-self pollen, leading to the recognition of six progeny classes from each individual plant. To facilitate an understanding of these processes we have developed a method for identifying individuals from different progeny classes based on the inheritance of introduced heterologous marker genes. This technique permits the screening of many thousands of seedlings at germination, and the consequent isolation of individuals associated with rare classes. Progeny profiles were determined for two apomictic accessions of Hieracium. Both were found to develop approximately 2.5% of their seed from meiotically derived eggs under the experimental conditions used and to have a rate of hybridity of approximately 2%. Evidence was also found for the action of a self-incompatibility mechanism operating in these plants despite the autonomous nature of apomixis in Hieracinum. As a demonstration of the utility of this approach, a study was conducted of polyembryony in one accession. The results indicate that there was a 7 fold greater likelihood that a meiotically derived seedling would arise in a polyembryonic seed than in a single-embryo seed. This indicates that facultative apomixis in Hieracium not only results from the simultaneous occurrence of sexual and asexual seed formation in the same capitulum as previously demonstrated, but most often as parallel processes within the same ovule.

The behavioural responses of flying western flower thrips (Frankliniella occidentalis Pergande) (Thysanoptera: Thripidae) to the colour yellow and the odour anisaldehyde were examined. In a wind tunnel, upwind flight by female thrips was common in an airflow of 0.11 m s −1 but was impeded at 0.22 m s −1 . In the absence of anisaldehyde, flying female thrips exhibited an oriented response towards a yellow cue in the wind tunnel at a wind speed of 0.11 m s −1 . The main response of females to anisaldehyde in the wind tunnel was flight inhibition. There was no evidence of an odour-induced visual response, an odour-induced anemotactic response or chemotaxis by female thrips to anisaldehyde in wind tunnel bioassays, but chemokinesis was implicated. With a matrix of yellow or black water traps with and without anisaldehyde in a greenhouse sweet pepper crop, yellow traps with anisaldehyde caught more thrips adults than yellow traps without anisaldehyde, black traps with anisaldehyde and black traps without anisaldehyde (1.3, 28 and 721 times for males respectively and 2.4, 9 and 117 times for females, respectively). Differences between respective traps were statistically significant in almost all cases. Trapping experiments using a centre-baited trap design to reduce the interaction of anisaldehyde between baited and unbaited traps were undertaken in tomato and sweet pepper greenhouse crops. When the spatial distribution of the thrips adult population within the greenhouse was taken into account, yellow water traps with anisaldehyde caught between 11 and 15 times more female and 3 and 20 times more male F. occidentalis adults than yellow traps without anisaldehyde.

The non-structural dry matter content of onion bulbs consists principally of fructose, glucose, sucrose and fructans.

Resistance to Ascochyta blight has been demonstrated within pea germplasm. Pea genotypes show dif-Ascochyta blight of pea (Pisum sativum L.) is a fungal disease ferences in resistance or susceptibility to M. pinodes and caused by Mycosphaerella pinodes (Berk. & Bloxham) Verstergren, P. medicaginis var. pinodella that is independent of the Phoma medicaginis Malbr. & Roum. var. pinodella (L.K. Jones) Boerema, and Ascochyta pisi Lib. that can result in significant reduc-virulence of the pathogen isolate (Onfroy et al., 1999; tions to pea yield and quality. To characterize the genetics of resistance Wroth, 1998a; Xue et al., 1998). Complete resistance to and to identify molecular markers for use in plant breeding, quantitainfection by either pathogen has not been observed in tive trait loci (QTLs) affecting Ascochyta blight resistance were pea. Using different germplasm, Wroth (1999) found mapped in F 2:3 and F 2:4 families produced from a cross between resistant that resistance to M. pinodes infection showed quantibreeding line 3148-A88 and susceptible cultivar Rovar. A linkage map tative inheritance, while Clulow et al. (1991) suggested containing 96 loci on 11 linkage groups was constructed for 133 families that resistance to M. pinodes showed major gene inherfrom this cross. Resistance of progeny lines to natural Ascochyta itance. blight epidemics was examined in field trials at Medina, Western Molecular linkage maps and mapping of QTLs are Australia, in 1997, 1998, and 1999. Disease severity was assessed on valuable tools for characterizing the genetics of disease stems, leaves, and pods by means of separate rating scales. Because pea shows increased susceptibility to Ascochyta blight as it matures, resistance, localizing resistance loci on linkage maps, plant reproductive stage was assessed at the time of disease scoring and identifying linked polymorphic DNA sequences in the 1998 and 1999 trials. Thirteen QTLs were detected for Ascothat might be used for marker-assisted selection (MAS) chyta blight resistance on seven linkage groups. Eight of these QTLs during plant breeding. QTL mapping has characterized were detected in multiple environments or by multiple trait scores.

Information is reviewed on root infection of potato by the plasmodiophorid Spongospora subterranea f. sp. subterranea. This pathogen has long been recognized as the cause of root galls (hyperplasia) and the economically important disease powdery scab on tubers (modified stolons). The significance for plant productivity of the zoosporangium stages of the pathogen in potato roots has only recently begun to be documented. Two experiments are described that assessed effects of S. subterranea root infection on potato plant root function and productivity. A greenhouse experiment measured root function and plant parameters for eight potato cultivars with markedly different susceptibilities to tuber powdery scab. Water uptake and plant growth were reduced by S. subterranea inoculation in all eight cultivars. The magnitudes of these negative effects, and intensities of root hyperplasia, differed among the cultivars, but were not related to respective susceptibilities to tuber powdery scab. A field trial assessed root function and plant productivity for a cultivar (Iwa) that is very susceptible to Spongospora tuber and root diseases. Soil water content beneath uninoculated plants was consistently less than for inoculated plants, indicating that inoculation reduced water uptake (root function). Inoculation reduced shoot and root dry weights, and reduced weight of tubers per plant by 42%. Spongospora subterranea causes three diseases of potato: root membrane dysfunction, root hyperplasia and tuber powdery scab. The root diseases caused by the pathogen are likely to be important both for powdery scab management and for deleterious effects on potato crop yields.

Uptake and translocation of 26 chemicals (herbicides, fungicides, growth regulators, insecticides and model compounds), formulated with and without ‘Ethylan TU’ (NP8) surfactant, have been determined 24, 48 and 72 h after spraying onto leaves of maize, rape, strawberry and sugar beet. Eight of the chemicals may be classified as polar (log partition coefficient (P) < 0) and 18 as lipophilic (log P 0·8‐4·6). Chemicals penetrated more readily into waxy leaves of rape and strawberry than into less‐waxy sugar beet, whilst lowest rates were observed for maize. Rates of uptake varied from exceedingly low (< 2% 72 h after application) for uracil, maleic hydrazide, isoproturon and methyl phenylurea applied to maize, to rapid (>98% within 24 h of application) for acephate and triadimefon applied to strawberry leaves. The effects of NP8 on rates of chemical uptake were classified into 4 types, viz:‐ low rates, with limited enhancement by NP8; high rates unaffected by NP8; marked enhancement by NP8 within 24 h; and continuous enhancement by NP8 over 0‐72 h. Translocation into the tissues immediately adjacent to the target site was greater for waxy than less‐waxy plants, enhancement by NP8 was attributed to its effects on penetration rather than to surfactant interactions at the sub‐cuticular level. Logarithms of physicochemical properties (partition coefficient, water solubility S, molecular weight MW), together with deposit area and melting point (m.p.) values were used to investigate relationships with uptake and translocation. In most cases the variability could not be described adequately in a simple linear form. Regressions using the entire group of 26 chemicals also showed poor correlations between uptake patterns and individual variables. Polynomials in log S, log P, log MW and m.p. were used to test for complex relationships. A quadratic polynomial in log P, log S and m.p. accounted for slightly more (77%) of the variability between the means for total uptake than a cubic polynomial in log P and log S (75%). Although both regressions were significant, the ‘lack of fit’ indicated that other factors need to be included to account fully for the variability in rates of uptake and translocation.