15N-labelled fertilizer urea was applied at increasing rates (0–200 kg N/ha), in spring, to winter wheat crops in the Canterbury region of New Zealand in three successive seasons (1993/94, 1994/95 and 1995/96). Recovery of fertilizer N by the crop (grain, chaff, straw and roots) ranged from 43–58% (mean 48%). The quantity of fertilizer N retained in the soil (0–40 cm), at harvest, ranged from 26–42%. Of the labelled N present in the soil, over 95% was present in organic form and 60–80% was retained in the surface 0–10 cm layer. Since soil organic matter represents a substantial sink for fertilizer N there is a need to characterize the nature of this organic pool of N more fully. The quantity of inorganic N present in the soil profile at harvest ranged from 20–46 kg N/ha and labelled fertilizer-derived N contributed less than 16% (mean 9·2%) to this inorganic pool. Loss of fertilizer N from the crop/soil system (i.e., labelled N not recovered in the crop or soil at harvest) varied from 12–26% (mean 18%). Losses were attributed mainly to denitrification since conditions were not conducive for ammonia volatilization or leaching of nitrate. In agreement with European research, it was concluded that almost all of the N at risk of leaching over the winter originates from mineralization of soil organic N and not from unused fertilizer-N applied in spring.

Field trials were undertaken in Suffolk in commercial crops of autumn-sown oilseed rape cv. Capricorn during 1993/94, cv. Apex in 1994/95. Plots were artificially infected with beet western yellows virus (BWYV) using viruliferous Myzus persicae, giving 73 to 94% infection. Control plots had natural infection ranging from 0 to 17·8%. Destructive plant samples were taken from each of the infected and control plots throughout the seasons for growth analyses, and final yields were measured on 44 m2 areas combine harvested from each plot. The seed yields of infected plots were 26 and 11% lower than control plots in 1994 and 1995 respectively (P<0·001).

Harvested seed yields were shown to be inversely proportional to the area of the plot that was inoculated with BWYV. Infection significantly lowered the oil content in 1995 from 47·9 to 46·8% (P<0·001), and increased glucosinolate levels from 16·12 to 18·37 μmol/g (P<0·01). BWYV caused a significant reduction in plant height and in numbers of primary branches in the 1993/94 trial and had an effect on the dry weight of the leaves, stalks, racemes and pods at some sample dates in both seasons. Virus-testing of infected plants showed that BWYV was present in the pod wall, the septum and seed coat; two of 78 embryo samples also contained virus. It was concluded that BWYV can cause significant yield losses in those years in which there is a high incidence of virus in the overwintered crops.

Pod and seed growth were studied in two experiments in which the plant's source-sink relationships were modified by (a) manually pruning an autumn-sown, indeterminate white lupin variety, Lunoble, to a determinate form, and (b) by growing a determinate variety, Lucyane, at densities ranging from 7 to 35 plants/m2. The pruning experiments indicated that the faster pod growth rate of determinate genotypes was not an inherent genetic trait but an indirect physiological consequence of the plant's changed architecture. In the density experiment, crop dry matter (DM) and nitrogen (N) were maximum at the end of pod extension in late July and similar across the plant density range at c. 12 t DM and 320 kg N/ha. Therefore, the amount of dry matter per plant decreased proportionately with the increase in plant number. The DM and N contents of the pod walls were also maximum at the end of pod extension, but seeds contained only a third of their final DM and a quarter of their final N. Protein accumulation during the final stages of seed growth, therefore, depended on the remobilization of nitrogen from other plant organs, primarily the leaves and pod walls. Nitrogen withdrawn from the leaves accounted for 44% of the gain in the pods, and N withdrawn from pod walls for 50–60% of the gain in the seed.

Seed number/m2 was the major yield component. Seeds and pods mainly aborted during early development, but seed number per pod was also decreased by some seed abortion after full pod extension, especially in first-order pods of plants grown at high density. The number of late-aborted seeds was negatively correlated with the amount of N remobilized from the pod wall. In determinate lupins, which have highly synchronous flowering and pod development, the large and sudden remobilization of nitrogen from leaves and pod walls for seed growth and protein accumulation triggered crop senescence.

Three landraces of bambara groundnut (Vigna subterranea (L.) Verdc.) were grown as crop stands in controlled environment glasshouses at the Tropical Crops Research Unit, University of Nottingham, in 1995. Two soil moisture treatments were imposed: irrigated to 90% field capacity each week and irrigated to 60% field capacity until establishment (27 days after sowing) with no further irrigation. Seasonal mean fractional interception varied between 0·20–0·37 for the droughted treatments and 0·62–0·74 for the irrigated treatments, resulting in cumulative intercepted radiation of 228–350 MJ/m2 and 662–794 MJ/m2, respectively. The maximum total dry matter (DM) produced was 5·8 t/ha at final harvest (145 days after sowing) with a pod yield of 2·7 t/ha. Under moisture stress there was little difference in DM production between landraces, with the highest total DM of 1·1 t/ha and a pod yield of 0·05 t/ha, representing a harvest index of 0·05 compared with an average of 0·46 for the irrigated treatments. The conversion coefficient was reduced from 1·00 under irrigation to 0·51 g DM/MJ radiation intercepted by soil moisture stress. Two of the landraces showed adaptive mechanisms to avoid drought; these are discussed in relation to maximizing seasonal radiation interception.

A semi-controlled environment study was conducted from May to September 1996 in Wageningen, The Netherlands, to investigate the interaction between growth and development in bambara groundnut (Vigna subterranea) and the influence of photoperiod on dry matter partitioning. The experimental design was a split-plot with four photoperiods (10·5, 11·8, 13·2 and 14·5 h/d) and two light treatments: unshaded and shaded (42% light reduction). The selection used was ‘DipC94’ from Botswana. The dates of 50% flowering and 50% podding were determined, and samples of plants were harvested at 22, 36, 50, 64, 78, 92, 106 and 120 days after sowing. Total dry matter production was 41% lower in the shaded treatment than in the unshaded treatment, but the rates of progress from sowing to flowering and flowering to podding decreased by only 3 and 12% respectively. This suggests that growth and development in bambara groundnut are largely independent. Photoperiod influenced dry matter partitioning indirectly, through its influence on the onset of podding. There were, however, no strong direct photoperiod effects on dry matter partitioning, either before or after the onset of podding.

The dynamic simulation model ‘PNUTGRO’ was used to predict groundnut growth and yield from 1989 to 1993 at Ludhiana, India. The simulated flowering, pegging and physiological maturity dates, leaf area index (LAI), pod and seed yields and shelling percentage of groundnut were compared with actual observations for the commonly grown cultivar, M-335. The simulated phenologic events showed deviations of only −3 to +3 days for flowering, −3 to +2 days for pegging and −4 to +2 days for physiological maturity of the crop. The model estimated the LAI to be within 95–108% (mean 101·5%) and shelling percentage to be within 93–108% (mean 100·5%) of the actual values. The model predicted the pod yields from 89 to 111% (mean 100%) and seed yield from 90 to 110% (mean 100%) of the observed yields. The results obtained with the model for the five consecutive crop seasons revealed satisfactory predictions of phenology, growth and yield of groundnut and hence the model ‘PNUTGRO’ can be used for prediction of groundnut production in the central plains of the Indian Punjab.

Changes in environmental conditions and the EU policy have put more emphasis on growing alternative crops in the set aside farmlands of western Europe, and sunflowers are increasingly being grown as a minor crop in the UK. However, long-term success of sunflowers as a commercial crop depends largely on the availability of early maturing, high yielding, disease resistant varieties. The present study was conducted to investigate the nature of genetic variation among the available breeding stocks that may have to be exploited to produce such cultivars. Analysis of 182 test crosses, produced by crossing 13 male sterile (CMS) lines with 14 restorer (SB) lines, has revealed that genetic variability exists for many important traits, including maturity, vigour and seed yield. Genetic differences were also detected within the male sterile and restorer groups of lines even though they were classed as early maturing. All types of gene effects, additive, dominance and epistasis, contributed to variation among the test crosses and dominance was largely unidirectional and partial. CMS and SB lines also showed some allelic complementation and the CMS exerted a modest degree of maternal control for flowering time. The test crosses were generally more vigorous and high yielding compared to their inbred parents. But they also matured significantly late, indicating that all crosses will not be suitable as potential hybrids for the UK conditions. Genotypic correlations indicated that faster growth, early flowering, high seed number and seed weight can be combined more readily in the F1 crosses.

In a preliminary experiment, 74 faba bean genotypes including winter genotypes (autumn-sown) and spring genotypes (spring-sown) and isogenic population pairs (tannin-containing v. tannin-free and vicine/convicine-high v. vicine/convicine-low), were analysed for the chemical composition of their seeds. A large variability was found for the main constituents (starch, protein and fibre). Autumn-sown genotypes contained 2·3% less proteins but 2·5% more starch in the seed dry matter (DM) than spring-sown genotypes. The vc− gene, which lowers the vicine and convicine contents, did not significantly modify the main seed components in the isogenic comparisons. The zt1 and zt2 genes, which eliminate condensed tannins in the seed coats, lowered by 2·1% the proportion of the seed coat in the DM. In the isogenic comparisons, the zt2 gene had a stronger effect than zt1 in reducing the total seed fibre and increasing the protein content.

In a second experiment, from the original 74 genotypes, 12 contrasted genotypes were selected and multiplied for animal nutrition trials. Their chemical analysis confirmed the variability between the faba bean categories observed in Expt 1, but detailed chemical analyses illustrated the variability in amino acid, fatty acid, amylose and oligosaccharide composition, trypsin inhibitory activity, condensed tannins, lectins and phytic phosphorus contents.

The synthesis and accumulation of tannins on tomato seedlings are regulated by environmental factors. The variation in the content of tannins was sufficiently important to bring about the occurrence of significant differences in the numbers of glasshouse whitefly on the seedlings. During a 2-week experiment, the treatments included mechanical wounding (20 prickings per cm2), spraying with kinetin solutions of 10−4 mol/dm3, plant growth regulators, and the atmosphere enrichment to 680 μmol CO2/mol air, the content of tannins being increased by c. 40, 70, 10–45 and 25% above the values obtained in the control. These results were correlated with a decrease in the numbers of insects occurring on the seedlings by c. 35, 45, 8–29 and 18%, respectively. Contrary to the above results the spraying with solutions of abscisic acid, gibberellic acid, and the incubation of plants in an atmosphere containing 170 μmol CO2/mol air, reduced the content of tannins by c. 69, 22 and 25%, respectively. This was reflected in the respective increases by c. 70, 40 and 35% in the numbers of insects occurring on the seedlings. The obtained results suggest that tannins seem to have a dosage-dependent effect on glasshouse whitefly. Decreasing the host plant quality by increasing tannin content may act as an important selective agent limiting the losses brought about by glasshouse whitefly in tomato cultivation.

Two field experiments were conducted during 1996–98 at Bangalore, India to study the effect of soil moisture regimes (0·3, 0·6 and 0·9 IW:CPE ratios) irrigation water:cumulative pan evaporation (IW:CPE) ratios and three rates of nitrogen application (0, 100 and 200 kg/ha) and in another experiment, three soil moisture regimes (0·3, 0·6 and 0·9 IW: CPE ratios), two rates of nitrogen application (100 and 200 kg/ha) and modified urea materials [prilled urea (PU) and dicyandiamide coated urea (DCDCU)] on oil content, herbage, oil yield and quality of geranium grown on altisols. Soil moisture maintained at 0·6 IW:CPE ratio significantly increased the herbage and oil yields of geranium. Application of 200 kg N/ha gave the maximum herbage and oil yield compared with those obtained from 0 and 100 kg N/ha. DCDCU produced higher yield than PU. The concentration and quality of essential oil were not influenced either by soil-moisture regime, rates or carriers of N.

This experiment examined the effect of feeding a concentrate diet ad libitum for two periods of time in two breeds of contrasting mature size cattle, on the activity of the components of the calpain system and the association between components of the calpain system and tenderness as determined by shear force in the longissimus muscle. Nine-month-old Angus and Simmental steers were either fed ad libitum on a feedlot from 9 months of age (F9) or on pasture until 25 months of age (F25) and then fed on the same ad libitum ration as the F9 steers. Groups within a breed were killed at mean liveweights of c. 800 kg for the Angus and 950 kg for the Simmental. Steers were slaughtered in a commercial abattoir and muscle samples collected from the longissimus muscle at the 13th rib within 60 min of slaughter. The activities of the components of the calpain system were determined 2 and 24 h post-slaughter. The length of time on the feedlot diet had the largest effect on shear force of the longissimus muscle and the activity of μ-calpain. The steers growing fastest prior to slaughter (F25) had the highest μ-calpain activities two h post-slaughter and produced the most tender meat, even though they were slightly older at slaughter. The best component of the calpain system for predicting shear force over all the treatments was the activity of calpastatin 24 h post-slaughter. This association between shear force 21 days post-slaughter and the activity of calpastatin 24 h post-slaughter was weak and varied between the treatments. The strongest associations occurred in the F9 Angus steers who also had the toughest meat and the slowest growth rates prior to slaughter.

Two experiments were conducted at Palmerston North, New Zealand during 1997, to investigate the effects of wilting chicory to reduce its bulkiness upon voluntary intake of fresh feed and dry matter (DM), apparent digestibility and voluntary water intake. In Expt 1 fresh chicory was cut and wilted for 48 h to determine the drying rate; wilting for 24 h increased DM content from 87 to 173 g/kg, reduced in vitro organic matter digestibility (OMD) by 0·016 (P<0·05) and was selected for use in Expt 2. In Expt 2, chicory was fed either fresh (113 g/kg DM) or wilted (250 g/kg DM) to castrated male red deer kept indoors over two time periods, late autumn and early spring. Chemical analyses showed that wilting slightly lowered the concentration of water-soluble carbohydrate from 185 to 158 g/kg DM, but did not change any other aspect of composition. There were no significant differences between fresh and wilted chicory in apparent digestibility of DM, organic matter (OM), hemicellulose and cellulose. Wilting significantly lowered voluntary intake of fresh feed (P<0·01), but significantly increased voluntary DM intake from 49 to 57 g DM/kg W0·75/day (P<0·05). Wilting chicory lowered feed water intake (P<0·01) but increased drinking water consumed (P<0·001), with total water intake still being slightly lower (P<0·05) for deer fed wilted chicory.

It was concluded that wilting chicory increased DM intake by reducing its bulkiness, without seriously affecting digestibility, and it is suggested that the feasibility of breeding forage chicory for higher leaf DM content should be investigated. A comparison with literature values showed that DM contents of fresh forages < c. 150 g/kg are likely to restrict the voluntary DM intake of ruminants.

Twelve female desert goat kids and an equal number of males were used to study meat production potential of desert goats at Kuku Research Station, Khartoum North, Sudan. The kids were kept in two separate groups according to sex. Kids were fed ad libitum a complete diet (a concentrate mix and green lucerne) for 147 days from 12 July to 10 Oct 1997.

Male kids consumed more dry matter, had significantly greater liveweight gain and had heavier slaughter weight and superior feed conversion efficiency than females. Carcass weight was significantly greater in males than females but females dressed out heavier than males. Male carcasses had more muscles and bone while female carcasses had more fat and trimmings.

Male goat kid carcasses yielded significantly (P<0·001) heavier wholesale cuts as single short forequarter and neck while female kid carcasses yielded heavier wholesale cuts as leg and chump, best end of neck as well as significantly (P<0·01) heavier loin and breast.

Maternal serum hormones (progesterone, oestradiol, triiodothyronine and cortisol) and blood metabolites (β-hydroxy butyric acid [BHBA] and blood urea nitrogen [BUN]) concentrations at weeks 0, 4, 8, 12, 16 and 20 of pregnancy were measured in 39 pregnant Javanese thin-tail ewes (20 and 19 carrying single and multiple [2–3] foetuses, respectively), and six non-pregnant ewes as controls, to evaluate their correlations with lamb birth weight at parturition. All hormones and metabolites changed with the advance of pregnancy. Regression analyses showed that concentrations of triiodothyronine, cortisol, BHBA, and BUN in the maternal circulation during pregnancy had lower correlations with lamb birth weight at parturition than those of progesterone and oestradiol. Progesterone and oestradiol concentrations in the maternal circulation at week 8 of pregnancy had the greatest correlations with lamb birth weight at parturition. The higher the concentrations of progesterone and oestradiol in the maternal circulation at week 8 of pregnancy, the higher the lamb birth weight at parturition. The results suggested that raising maternal serum progesterone and oestradiol concentrations during early pregnancy in sheep, either by exogenous administration or superovulation, might improve prenatal growth and lamb birth weight.

The intake and digestion of fresh and dried Digitaria decumbens grass by rams was compared using a 2×2 factorial design. The experiment took place in Guadeloupe (French West Indies) in 1996. Eight rams (mean liveweight: 45·7±3·1 kg) were maintained in metabolism cages. Digitaria decumbens grass was cut daily and distributed to four of them, the other four were fed the following day with the equivalent forage which had meanwhile been dried for 20 h at 60°C. Chemical composition (g/kg of dry matter (DM)) of the two diets based on neutral detergent fibre (NDF, 713, S.E. 18), acid detergent fibre (ADF, 361, S.E. 13) and crude protein (CP, 90, S.E. 4) was similar. The DM intake (61·0 and 53·2 g/W0·75, S.E. 2·0, P<0·05), the NDF (0·753 and 0·727, S.E. 0·004, P<0·011) and CP (0·588 and 0·544, S.E. 0·014, P<0·09) total tract digestibility of fresh and dried herbage were different. Nylon bag estimates of effective DM degradability and fractional degradation rates (per h) in the rumen were 0·436, 0·414 (S.E. 0·005, P<0·004) and 0·048, 0·038 (S.E. 0·002, P<0·02) for fresh and dried grass, respectively. Rumen digestibility of organic matter and NDF were 0·516, 0·541 (S.E. 0·021) and 0·763, 0·692 (S.E. 0·019), respectively. The rumen turnover rates of particles (per h) were 0·024 and 0·015 (S.E. 0·001, P<0·05) for fresh and dried forage respectively. The efficiency of microbial protein synthesis (g microbial nitrogen/kg organic matter apparently degraded in the rumen) was similar with the two diets : 33·5 and 33·0 (S.E. 3·3, P<0·9) for fresh and dried forage respectively. In conclusion, fresh Digitaria decumbens was nutritionally superior to dried. This is probably due to a faster degradation rate and a lower rumen retention time of the fresh forage.