Inclusion in the diet of concentrations of vitamin E and selenium (Se) above requirement is associated with variable improvements in animal performance and immune function. At the cellular and molecular level, research in the last decade has produced a clearer understanding of the mechanisms underlying the multiple functions of vitamin E and Se and it is apparent that these functions extend beyond antioxidant protection. This paper reviews recent research relating to the functionality of vitamin E and Se in relation to the ewe and her lambs and attempts to relate this understanding to the whole animal level. Important aspects of this improved understanding are descriptions of three groups of seleno-proteins and the appreciation that there is a hierarchy in both the distribution of selenium between tissues and in the synthesis of different enzymes within tissues. In addition, there is diversity in the effects of vitamin E and Se derivatives on immune cell function. Given this heterogeneity in function it is not surprising that published responses for the production and health of ewes and lambs to supplementary vitamin E and selenium are variable and not always positive. Coupled with information on factors influencing variability in supply of vitamin E and Se from fresh and conserved forages and concentrate supplements, this review highlights the need for greater awareness of the importance of adequate supplementation of ewe and lamb diets with vitamin E and Se.

Three experiments have investigated the effect of the timing of control of infestations of volunteer barley (Hordeum vulgare), Stellaria media and Galium aparine on the growth and yield of winter oilseed rape (Brassica napus). Although the experiments used conventional herbicides to achieve the different timings of control, the work was done in the context of the commercialization of herbicide-tolerant oilseed rape, where treatments could be applied at any time from autumn to spring. In the three seasons studied, oilseed rape growth was particularly vigorous in the autumn and, as a consequence, the competitive impact of the weeds was lower than anticipated. Untreated volunteer barley and G. aparine reduced yields in one and two experiments, respectively. However, in all experiments volunteer barley reduced crop growth in winter and spring severely, even though January treatments prevented yield loss in these vigorous crops. Delayed control of this weed would not be advisable if the weed was particularly dense or the crop less vigorous. In contrast, the G. aparine had no effect on crop growth and was only really apparent in the crop in late summer, so delaying treatment until even March would not put yields at risk. In one year, S. media markedly reduced crop growth in late winter but in the second experiment this did not occur. Consequently, as with the G. aparine, delayed autumn control would be unlikely to jeopardize yields. Thus, if herbicide-tolerant crops are commercialized in Europe, there will be flexibility in timing of application of herbicides to control broad-leaved weeds in winter rape but there would be a risk of yield loss from delayed control of volunteer cereals.

The success of GM herbicide tolerant canola is demonstrated by its acceptance by the farm community in Canada. There have been continuing comments, however, including some from major customers, suggesting that GM canola has lower quality than conventional canola. Data drawn from both the Western Canada Canola/Rapeseed Co-operative Test data from 1998–2001 and from the Canadian Grain Commission's harvest surveys of canola from 1996–2001 were used to compare the quality of GM and conventional canola registered and grown. Weed seed contamination of harvest survey samples decreased significantly as the herbicide tolerant lines increased in production. While variety registration data suggested GM and conventional lines had no differences in oil content, data from harvest surveys suggested that GM lines tended to have slightly higher oil contents. Protein and oil contents remain inversely related with no differences in the inverse relationship due to GM. While registration requires that all lines have less than 12 micromoles per gram of glucosinolates, data from harvest surveys show GM lines to have significantly less glucosinolates than conventional lines, possibly due to decreased contamination with cruciferous weeds. A comparison of glucosinolate contents between non-GM herbicide tolerant canola and conventional non-herbicide tolerant canola showed similar differences. There were no significant differences in chlorophyll content, erucic acid levels or saturated fatty acids but harvest survey data showed GM lines were slightly more unsaturated than conventional lines. It would seem safe to conclude that differences in quality between GM and conventional canola are due to the functioning of the GM trait – herbicide tolerance – that allows the GM canola to perform to its potential in the field.

On the basis of Finnish statutory variety trial data, the contribution of new varieties to cereal yields has been investigated. Such data have been collected since 1973. The data used contained the results of 2037 field trials testing 224 new barley cultivars, 163 new oat cultivars, 154 new spring wheat cultivars, 48 new winter wheat cultivars and 52 new winter rye cultivars. The data indicated a continuous increase in the annual yield of all the cereal species. The increase could be attributed in part to the genetic improvement of varieties and in part to changes in farming practices and environmental conditions. By using modern mixed model techniques it was possible to separate the effects due to genetic improvement from those due to the other factors. The main results show that in 1973–2003, new varieties contributed to an increase of 0·64, 0·41, 1·01, 0·63 and 0·97%, respectively, in the mean annual yield of barley, oats, spring wheat, winter wheat and winter rye. The research approach was based solely on existing data; new field experiments were not needed.

‘Mal de Río Cuarto’ (MRC) disease, caused by a member of the family Reoviridae belonging to the genus Fijivirus, is considered to be the most damaging viral disease of maize (Zea mays L.) in Argentina. Resistance to MRC disease is a quantitative trait with moderate heritability ranging from 0·44 to 0·56. The objective of this study was to identify simple sequence repeats (SSR) loci linked to quantitative trait loci (QTL) contributing to MRC disease resistance. Two hundred and twenty-seven F3 derived-lines from a cross between a susceptible inbred line, Mo17, and a partially resistant inbred line, BLS14, were evaluated across four Río Cuarto environments. A disease severity index (DSI) based on disease grades was calculated and used to rate F3 derived-lines for their resistance to MRC disease. A subset of parental F2 plants belonging to susceptible and resistant F3 derived-lines from field assessments was assayed for 180 SSR primer pairs to map resistance genes. Fifty-six maize SSR were employed for the testing of linkage among DNA markers and the mapping of QTL through composite interval mapping. Resistance to MRC disease was affected by two QTL on chromosomes 1 and 8 which showed overdominance and dominant gene action, respectively. A simultaneous fit with these QTL in the joint analyses explained 36·2% of the phenotypic variance. In spite of the fact that relative efficiency of marker-assisted selection (MAS) in comparison to phenotypic selection was close to 1, the mapped QTL could improve the efficiency of efforts in breeding for resistance to MRC disease.

Canopy development, radiation absorption and its utilization for yield was studied in four grain legume species Cicer arietinum, Lens culinaris, Lupinus angustifolius and Pisum sativum. The grain legumes were grown at different plant populations and sowing depths over two seasons in Canterbury, New Zealand. The green area index (GAI), intercepted radiation, radiation use efficiency (RUE) and total intercepted photosynthetically active radiation (PAR) increased significantly (P<0·001) with increased plant population. Narrow-leafed lupin produced the highest maximum biomass (878 and 972 g/m2, averaged over all populations during 1998/99 and 1999/2000, respectively) and intercepted more radiation (600 and 714 MJ/m2, averaged over all populations during 1998/99 and 1999/2000, respectively) than the other three legumes. In all four species, in both trials, the highest plant populations reached their peak GAI about 7–10 days earlier than legumes sown at low populations. Cumulative intercepted PAR was strongly associated with seed yield and crop harvest index (CHI).

The RUE increased (from 1·10 to 1·46 and from 1·04 to 1·34 g/MJ during 1998/99 and 1999/2000, respectively) as plant population increased and was highest in the highest yielding species (e.g. 146 and 1·36 g/MJ for narrow-leafed lupin in both experiments). The larger leaf canopies produced at the higher plant populations reduced the extinction coefficient (k).

The results suggest that in the subhumid temperate environment of Canterbury, grain legume species should be selected for the development of a large GAI. This should maximize PAR interception, DM production and, consequently, seed yield.

The partitioning of above ground nitrogen (N) in chickpea (Cicer arietinum), lentil (Lens culinaris), lupin (Lupinus angustifolius) and pea (Pisum sativum) at crop maturity was investigated. The plants were grown at different plant populations and sowing depths in 1998/99 and 1999/2000 in Canterbury, New Zealand. In all four legumes the N concentration was highest in seed (29–36 mg/g N) followed by senescent leaves. The lowest N concentration was in stems. Lupin had the highest seed N yield at 16·82 and 19·29 g/m2 followed by chickpea at 10·26 and 13·10 g/m2, in 1998/99 and 1999/2000, respectively. Lentil had the lowest N concentrations and yield. The distribution of N to all legume plant parts increased as population increased up to twice the optimum and 400 plants/m2 in 1998/99 and 1999/2000, respectively. Over all plant populations, the nitrogen harvest index (NHI) was stable in each of the four species across the two seasons. However, the NHI changed with changes in plant population and sowing depth. The N accumulation efficiency (EN) was highest in lentil at 0·024 and 0·027 g N/g DM and lowest in chickpea at 0·018 and 0·021 g N/g DM in 1998/99 and 1999/2000, respectively. The NHI and the crop harvest index (CHI) were correlated and both were strongly associated with seed yield. Thus, NHI might be useful as a selection criterion to improve seed yield in grain legumes.

Nitrogen (N) levels in the soil and N fertilization are among the major factors that affect grain protein concentration (GPC) in malting barley (Hordeum vulgare L.). The use of inherently low protein cultivars might be an advantage in conditions of excessive soil N or in situations where N is applied to maximize yield. In the present study, eight malting barley genotypes were grown under dryland and irrigated conditions to compare their response to four rates of nitrogen (N) application (0, 30, 60 and 120 kg/ha). The trials were carried out in 1998 and 1999 at a site in the Wimmera region of Victoria, Australia, which has a Mediterranean-type environment. Seasonal differences accounted for a large proportion of the observed variation in GPC, but had little influence on variation in grain yield. Nitrogen application significantly increased grain yield and GPC, and decreased kernel weight and plumpness. The rate of response for grain protein was higher under dryland than irrigated conditions, but the genotype-by-nitrogen interaction was not significant under both conditions. To further characterize genotypic response, the method of pattern analysis was used to identify groups of genotypes showing a similar pattern in their response to N application and to relate the patterns to available knowledge about the inherent GPC of their grains. The eight genotypes were clustered into three entry groups, corresponding to low, moderate and high-protein genotypes. There was little difference among groups in the rate of response to N application. However, the genotype group with inherently low GPC maintained the lower protein over those with higher grain protein at the different rates of N application. Under dryland conditions, the low-protein genotypes tended to have less plump kernels with increasing rates of N application than the respective high-protein group.

Four perennial ryegrass growth models were evaluated for their suitability to form the basis of a herbage growth model (HGM) for a decision support system (DSS). The successful candidate had to be suitable for further development to meet the specification of the DSS and following redevelopment it would then be integrated into a pasture management decision support system for dairy production. The models selected for evaluation were the Irish produced Brereton model (Brereton et al. 1996), the LINGRA model (Schapendonk et al. 1998), produced in the Netherlands, and a version of the English Johnson & Thornley (1985) model, developed for field use at the Northern Ireland Plant Testing Station (Laidlaw & Gilliland 2000). The fourth model was a version of the LINGRA model, simplistically adapted by the authors to take account of reproductive growth (LINGRARep). The performance of the models was tested using the mean squared prediction error (MSPE) against a total of 28 seasons' growth data, collected from two sites; i.e. at the former Grassland Research Institute at Hurley, England and the Northern Ireland Plant Testing Station at Crossnacreevy. The Brereton model, when validated against the Hurley dataset, had the lowest MSPE of the four models, but had the highest MSPE against Crossnacreevy data. The PTS model did not perform as well as expected considering its mechanistic basis. Equally, the performance of the LINGRA model was poor at both sites. However, the LINGRARep performed well, having the lowest MSPE at Crossnacreevy and second lowest at Hurley. The LINGRA model was selected for development as the final HGM given that it proved suitable for adaptation and by making even simple adaptations, as in LINGRARep, its performance could be substantially improved. Therefore, it was considered that it possessed the greatest potential for further development.

Visible (VIS) and near-infrared reflectance spectroscopy (NIRS) combined with multivariate data analysis was used to predict potentially mineralizable nitrogen (PMN) and nitrogen in particulate organic matter fractions (PSOM-N). Soil samples from a long-term experiment (n=24) as well as soils under commercial management (n=160) in Uruguay (South America) were analysed. Samples were scanned in a NIRS 6500 monochromator instrument by reflectance (400–2500 nm). Modified partial least square regression (MPLS) and cross validation were used to develop the calibration models between NIRS data and reference values. NIRS calibration models gave a coefficient of determination for the calibration (R2CAL)>0·80 and the standard deviation of reference data to standard error in cross validation (RPD) ratio ranging from 2 to 5·5 for the variables evaluated. The results obtained in the study showed that NIRS could have the potential to determine PMN and PSOM-N fractions in soils under different agronomic conditions. However, the relatively limited number of samples led us to be cautious in terms of conclusions and to extend the results of this work to similar conditions.

Two field trials were conducted in the 1999 and 2000 cropping seasons to determine the effect of planting date and host plant resistance on grain mould and anthracnose, and host plant resistance with fungicides on anthracnose of sorghum in the Nigerian northern Guinea Savanna. Three sorghum varieties were used [SAMSORG 40 (ICSV 111), SAMSORG 4 (KSV 4) (both early maturing and susceptible to anthracnose) and SAMSORG 14 (KSV 8) (medium maturing and resistant to anthracnose)]. Results show that early planting in June and the first 2 weeks of July predisposed susceptible varieties to high level of anthracnose while planting in June predisposed SAMSORG 40 and SAMSORG 4 to high levels of grain mould but gave highest grain yield for the three varieties. The resistant variety SAMSORG 14 was resistant to both anthracnose and grain mould irrespective of planting date. Foliar application with benomyl controlled anthracnose and gave highest yields when combined with seed treatment using metalaxyl+carboxin+furathiocarb (MCF). However, seed treatment alone with MCF did not control anthracnose.

In previous comparative studies of buffaloes and temperate cattle, a greater increase in rectal temperature (RT) and skin temperature (ST), and a greater decrease in haematocrit (Ht) have been observed in buffaloes than in temperate cattle with an increase in ambient temperature (AT). Our series of previous experiments suggested that great changes in RT, ST and Ht are induced in buffaloes by a marked increase in blood flow from the body core to the surface, which accelerates dissipation of heat from the skin surface. On the basis of these suggestions, the present study was undertaken to compare fluctuations in RT, ST and Ht between buffaloes and tropical cattle. Fluctuations in the aforementioned parameters, particularly RT and Ht, were greater in buffaloes than in cattle. Moreover, the correlation for RT or Ht v. AT was significant for buffaloes (r=0·33 and −0·37, respectively) but not for cattle. The correlation coefficient for ST v. AT was significant in both species, but was greater in buffaloes (r=0·63) than in cattle (r=0·56). These results demonstrate that with changes in ambient temperature, RT, ST and Ht fluctuate much more in buffaloes than in tropical cattle, as found previously for temperate cattle. Therefore, the distinctive thermoregulatory responses of buffalo are confirmed as being specific to this species.

A 3-year study was set up to evaluate the influence of cow genetic potential for milk production and concentrate supplementation level on profitability of pasture based systems of milk production. In each of the 3 years, 96 cows were used in a three (genotype)×3 (levels of concentrate supplementation) randomized block design. Cows were categorized based on their pedigree index (PD) for milk production (PDMILK) into low (LP; PDMILK less than 100 kg), medium (MP; PDMILK 100–200 kg) and high (HP; PDMILK 200–300 kg). Concentrate supplementation levels were 376, 810 and 1540 kg per cow per lactation, identified as low (LC), medium (MC) and high (HC) concentrate respectively. Three milk production scenarios were investigated using the Moorepark Dairy Systems Model (MDSM) which included: EU milk quota applied at farm level with current costs and prices (S1), EU quota applied at farm level with projected future costs and prices (S2), and EU milk quota applied at industry level (quota purchasing possible) with projected future costs and prices (S3). The effect of variation in milk price, concentrate price and opportunity cost of land were modelled using stochastic budgeting. The results suggest that where EU milk quota is applied at farm level (S1 and S2), the optimum system of milk production is where margin per unit of output is maximized. When milk quota is applied at industry level (S3) the optimum system will be where margin per cow will be maximized. The results also suggest that the optimum system for cows with lower genetic potential for milk production is low level of concentrate supplementation, while cows with higher genetic potential for milk production is high level of concentrate supplementation.