Three field experiments were conducted on sandy-loam soils comparing the effects of triazole, strobilurin and oxazolidinedione fungicides applied at flag leaf emergence and again at ear emergence to wheat between 1998 and 2000. Cultivars Hereward and Consort were included in all 3 years, Cockpit in 1999 and 2000 and Charger in 1999. Foliar disease, green area of the flag leaf, grain weight and moisture content were assessed weekly during grain filling and senescence. Grain yield, 1000 grain weight (TGW) and specific weights were measured at harvest maturity. Septoria tritici was the dominant disease in all cultivars except Cockpit, where Puccinia striiformis caused most damage. Consort was more affected than Hereward by S. tritici in all years. Effects of fungicides on disease control were usually reflected in green flag leaf area duration (GFLAD), with large gains in Consort and Cockpit. In 2000, however, fungicides increased GFLAD of Hereward and Consort by similar amounts. Apical grains had smaller water content than medially placed grains. Maximum water content was positively influenced by fungicides where significant disease was controlled before maximum grain weight had been attained. Grain weight in Hereward was less affected than other cultivars by fungicides in both positions. Grain filling rates varied between cultivar and ear position by inconsistent and small amounts, but large and significant gains from fungicide treatment were made in grain filling periods. These varied from 0·16 days per day GFLAD in Hereward to 0·69 days per day GFLAD in Consort in apical grains in 2000. Gains in GFLAD were associated with increased yield, TGW and specific weight, but these relationships varied with cultivar. Increases in GFLAD by fungicide in Hereward in 2000 occurred much later relative to grain filling and thus after the time of maximum grain water content, resulting in smaller gains in filling duration, yield, TGW and specific weight than that seen in Consort. There was no evidence of differing relationships between GFLAD and yield for the different fungicide groups used in these experiments.

Experiments were conducted in controlled environmental chambers to study the effects of temperature on leaf emergence and leaf growth of main stem in winter barley (Hordeum vulgare L.) plants. Plants of the cultivar, Kikai Hadaka, were grown at constant temperatures between 12·5 to 27·5 °C. The leaf number on the main stems was counted (in Haun units) every day from the emergence of the third leaf until the emergence of the seventh leaf. The area was measured from the second to the sixth leaves on the main stems. The emergence of new leaves was a linear function of time at all temperature regimes. The leaf emergence rate increased with increasing temperature until an optimum temperature of 22·5 °C was reached and then decreased with further increasing temperature, but not significantly, compared with the peak. The leaf emergence rate per degree-day (DD) was slower with increasing temperature. The leaf growth rate increased with increasing temperature until an optimum temperature of 20·0 °C was reached and then declined with further increases in temperature. The leaf growth rate per DD had its maximum at 17·5 °C. The leaf emergence and leaf growth under different temperatures but at the same DD were different. The responses to temperatures for emergence and growth of barley leaves were different. These results suggest that a fully developed concept of the relationship of temperature to plant development and growth is an important aspect of increasing the accuracy of dynamic crop simulation models.

A series of tropical maize hybrids, involving 10 single, four double and four three-way crosses were evaluated with their parental inbred lines and three control varieties, at Universiti Putra Malaysia, Serdang, Malaysia, in a randomized complete block design, with three replications. The objectives were to identify hybrids superior for yield, yield components and other agronomic traits, to estimate heterosis revealed by the hybrids, and to estimate broad-sense heritability for important characters in the populations. The hybrids were found to vary highly for grain yield and most other traits measured. High estimates of heterosis were shown by grain yield, ear weight and grain weight per ear, moderate for plant and ear heights, shelling percentage, ear diameter, number of kernel rows per ear, number of kernels per ear row and 100-grain weight. The hybrids flowered and matured earlier than their respective inbred parents. Estimates of broad-sense heritability also varied with characters. Moderate heritability was shown for grain yield indicating a substantial amount of genetic variation in this population of hybrids. Low and negligible heritability for days to silking and 100-grain weight indicate that these traits were very much influenced by environmental factors. Based on the overall performance of the hybrids, the single cross, SC-2, the double cross, DC-11 and the three-way cross, TWC-15, were found to have high potential. No obvious differences were observed in performance among the three categories of hybrids, the single, double and three-way crosses.

A replicated field plot experiment was carried out in Northern Ireland in 1996 with flax, cv Ariane, and linseed, cv Flanders, each grown at seed rates of 500, 1000 and 1500 seeds/m2, in which a comparison was made between retting of the standing crop, following desiccation by the trimesium salt of glyphosate (Touchdown, Zeneca Ltd.), and water or dew retting of the pulled crop. Application at 4 litres/ha on 9 August, 33 days after the mid-point of flowering (MPF), achieved both desiccation and partial retting of the crop within 14 days. Over 16% clean long fibre was extracted by scutching the stand-retted flax straw, yielding 800 kg/ha fibre, while water retting achieved 20% extraction and 980 kg/ha yield and dew retting 8·5% and 420 kg/ha respectively. The dew retting was uneven, resulting in high losses during fibre extraction, while water retting for 7 days at 25 °C did not achieve complete retting resulting in a high content of woody fragments in the fibre. Fibre yields increased by almost 50% with the high v. low seed rate. Linseed was less well retted than flax and contained higher levels of impurity in the extracted long fibre which, after retting, yielded 120 to 310 kg/ha at extraction rates of 2·9% to 7·5%.

In a second experiment in 1998 flax cvs. Viola and Evelyn were treated with the timesium salt of glyphosate at rates of 2, 4 or 6 litres/ha 10, 20, 30 or 40 days after MPF on 5 July. Viola desiccated satisfactorily at all spray dates with 4 and 6 litres/ha glyphosate. The 20-day treatment desiccated more slowly than the 30-day and the 2 litres/ha rate did not achieve complete desiccation, but the trimesium salt of glyphosate achieved better desiccation at this timing than that found in earlier studies with the original form of glyphosate. Evelyn desiccated more slowly and less evenly than Viola particularly at the 20-day and 40-day timings. Spraying at MPF+10 days interrupted early development of the seed and fibre significantly reducing yields. Due to slower desiccation the 20-day timing was no better than the 30-day, which was well retted by harvest 44 days after spraying, and gave the highest yield of clean long fibre. The spraying 40 days after MPF was considered too late in the season to be of practical use. It was concluded that retting of standing flax following desiccation with the trimesium salt of glyphosate was more effective than with the earlier formulation and that retting of the standing crop could achieve equivalent or better retting with similar fibre yields to traditional retting methods. The optimum spray timing was found to be about 30 days after MPF with 4 or 6 litres/ha, the lower rate being adequate for glyphosate responsive varieties such as Viola.

Two non-dwarf and two dwarf, autumn-sown determinate genotypes of white lupin (Lupinus albus L.) were sown at three sites in north-west Europe in the crop years, 1995–96, 1996–97 and 1997–98. Fully factorial experimental designs were used to analyse all combinations of genotype, seed rate and row spacing. Canopy expansion, expressed as the percentage of Photosynthetically Active Radiation (PAR) intercepted, and above ground dry matter (DM) accumulation were measured at frequent intervals during the main growing season at Rothamsted in the UK and Lusignan in France. The data from Rothamsted were used to derive models for the two processes, which were compared to the data from Lusignan, France.

Crops with more than 23 plants/m2, 25 main stem leaves per plant or 1400 leaves/m2 were able to intercept more than 80% of the incident PAR. There were small differences in canopy expansion between genotypes. The non-dwarf genotypes began expansion slightly earlier (100–150 °Cd or thermal time in °Cdays, base temperature = 3 °C) than the dwarf genotypes. Crops sown on rows wider than 40 cm apart or with low plant densities (less than 23 plants/m2) were also slower to expand the canopy and intercept the PAR.

The maximum quantity of dry matter accumulated by a genotype in the season (476–1044 g/m2) was related by a conversion efficiency (e) to the cumulative quantity of PAR intercepted. Values of e were generally in the range 0·92–1·65 g DM/MJ PAR during the early part of the growing season, which was comparable with other work on temperate-zone grain legumes. The non-dwarf genotype Ludet achieved an unusually large value of e (3·13 g DM/MJ PAR) and accumulated 1355 g DM/m2 at Lusignan in 1998. Late season drought in 1995–96 at Rothamsted produced some low values of e (0·75 and 0·88 g DM/MJ PAR).

The seed yield was not related to the quantity of dry matter accumulated as harvest index varied from 22·3% to 49·7%. Maximum seed yield (4·54 t/ha) was produced from a low plant density (15·9 plants/m2). Mutual shading, caused by any combination of high plant densities, large numbers of leaves per plant or sowing on wide rows (>40 cm; at high plant densities within the rows) appeared to limit seed yield potential.

Hermetic cold storage without previous drying (wet–cold storage) was experimented for the preservation of yam pollen grains. Pollens collected from white yam D. rotundata and a wild relative, D. praehensilis, were stored at −80, −20, 5, and 15 °C in sealed packs for 2 years. Pollen samples were drawn for in vitro germination tests after 100 and 700 days, and hand pollination was conducted after 365 and 730 days in storage. Pollen germination responses were not significantly different among the two species. Though pollen maintained germination capacity at all the storage temperature regimes, there was a significant loss in the viability of pollen stored at 5 and 15 °C after 100 days of storage. After 700 days in storage, pollens stored at 5 and 15 °C had lost germination capacity while there were no significant differences in the germination of fresh pollen and pollen frozen at −80 and −20 °C. Hand pollination with pollen of D. rotundata frozen at −80 °C for 365 days gave 69·5% fruit set and 50% fruit set after 730 days in storage. From these results, the wet–freeze procedure appears promising to execute the establishment of pollen gene banks for yam breeding and for conservation of haploid gene pool of yams in base collections. A pollen storage protocol based on the procedure is recommended.

Many authors report on the effect of rice–fish culture on rice yields. Some reports show increased rice yields, others show no effect or even decreased yields. To verify the impact of rice–fish culture, data gathered over eight experiments (1995–1999) at the Co Do experimental rice–fish station, Vietnam, were analysed through multiple regressions with rice yield and different yield components as the dependent variables. We used eight independent variables: season, water depth, rice variety, rice seeding rate, and the effective stocking density (ESD) of silver barb, Nile tilapia, common carp and snakeskin gourami. Season had the biggest impact on nearly all dependent variables. Rice yields in the wet season were on average 2·42 t/ha lower as compared to the dry season. Higher water levels decreased the number of panicles/m2 and the rice yield. The rice seeding rate affected the yield component variables, but had no impact on the rice yield. Silver barb feeding decreased the number of panicles/m2 but this was compensated by an increased number of grains/panicle. Snakeskin gourami had a positive effect on panicles/m2 and, together with common carp, on sink capacity, probably through improved nutrient cycling in presence of fish and improved nutrient uptake by the rice plant. Snakeskin gourami had a negative effect on the ripening ability, whereas Nile tilapia had a positive effect. Fish did not have any impact on the rice yield. Increased water level and reduced rice arable area, the main two requirements for rice–fish culture, result in lower rice yields from rice–fish systems as compared to monoculture systems.

So far, little has been done on the effect of nitrogen fertilizer on intake and digestibility in tropical grazing conditions. The effect of two nitrogen levels, 0 (NF) and 50 kg/ha (F) for three successive grazing cycles, on organic matter intake (OMi) and digestibility (OMd) for Creole heifers (208 kg live weight) was determined. Two groups of four tethered heifers, allowed 18 kg of dry matter daily, grazed individual NF or F circular areas at 28 re-growth days. The heifers were moved and watered daily. Sward characteristics (height, herbage mass, morphological and chemical composition and in situ tiller measurements), OMi, OMd and feeding behaviour (biting rate, bite size, intake rate, grazing and ruminating times) were evaluated simultaneously per circular area.

Under nitrogen fertilizer, the stems elongated rapidly (by 133%) as did the leaves, but to a lesser extent (by 40%). Consequently, canopy height, leaf and stem masses and crude protein content increased (respectively by 100%, 66%, 186% and 40%), while total bulk density decreased (by 10·5%). Throughout the successive grazing cycles, there was a particular effect on leaf number, both in the F and NF swards, whereas this parameter was not affected by the fertilizer level. Under fertilizer, OMi and OMd were both 9% greater than for the NF sward. The increase in herbage CP content partly explains the rise in OMi, and there is evidence that rumen load has a determining effect on OMi. Leaf mass is the major factor accounting for the 9% increase in OMd under fertilizer regime. On the other hand, whatever the fertilizer regime, OMd was positively influenced by the greater leaf number throughout the grazing cycles. Biting rate, bite size and intake rate were determined respectively by sward height, CP content and stem fraction, whereas grazing and ruminating times were partially influenced by sward characteristics.

Atriplex nummularia L. (atriplex) foliage and urea-treated straw have been used as nitrogen supplements for Barbarine lambs given Opuntia ficus-indica f. inermis (cactus) and their effects on feed intake, diet apparent digestibility, nitrogen balance and daily gain have been evaluated. Twenty-four lambs (mean live weight 19·9±2·79 kg) were randomly allocated to one of four experimental groups, groups 1–3 received freshly cut pads of cactus ad libitum. Group 1 was supplemented with 600 g untreated barley straw (C+US), while group 2 received 600 g urea-treated straw (C+UTS). Group 3 received 600 g untreated straw and 400 g atriplex (C+A). The amount of atriplex was calculated so that groups 2 and 3 receive iso-nitrogenous diets (i.e. C+UTS and C+A). Group 4 (US+BW) received a diet commonly offered to sheep by Tunisian smallholders, untreated straw ad libitum and 400 g of ground barley grain and wheat bran mixture (50[ratio ]50). A growth trial (60 days) followed by a digestibility trial (8 days) were performed in 1999. Irrespective of dietary treatment, cactus intake was high, averaging 500 g dry matter (DM)/day. It was not affected (P>0·05) with N supplementation, as urea-treated straw or atriplex. Sheep fed cactus-containing diets drank considerably less (P<0·001) water than those on the common diet (US+BW). Nitrogen provision improved significantly apparent digestibility of cactus-based diets. Urea treatment of straw increased content of digestible dry matter, organic matter, crude protein and cell wall (NDF) by 100, 100, 120 and 290 g/kg diet, respectively. There was a further increase when atriplex was provided instead of urea-treated straw. Nitrogen balance was positive across all dietary treatments but was improved when the nitrogen content of cactus-based diets was increased. Sheep fed on cactus and supplemented with atriplex retained the same amount of N as those fed the common diet (US+BW). The efficiency of microbial N production, estimated by the urinary excretion of allantoin, was improved (P<0·05) with N supplementation of cactus-diets (5·7, 12·4 and 11·4 mg/kg digestible OM intake for diets C+US, C+UTS, C+A, respectively). The diet C+US covered maintenance requirements of the sheep (7·7 g of daily gain). Nitrogen supplementation of cactus-based diets raised the average daily gain of lambs. Indeed, sheep given C+UTS or C+A diets grew at a rate of 19·9 or 31·4 g/day, respectively. It is noteworthy to mention that C+A and US+BW diets had similar effect (P>0·05) on sheep growth (31·4 and 39·7 g/day, respectively). It is concluded that cactus may be considered as an emergency feed and water source for sheep in arid and semi-arid zones. Nitrogen supplementation of cactus-based diets with urea-treated straw or atriplex foliage improved the feeding value of these diets and consequently sheep growth. A cactus-based diet, supplemented with atriplex, promoted similar growth in sheep as the commonly used diet (US+BW).

Two experiments were conducted to evaluate the effect of short transport stress on ewes during di-oestrus and pro-oestrus. In Experiment 1, intra-vaginal sponges containing fluorogestone acetate were inserted into ewes for a period of 12 days. A gonadotrophin (PMSG) injection was given at the time of sponge withdrawal to induce oestrous. To dissociate the possible effect of PMSG during pro-oestrus, a second experiment was designed in which prostaglandin was used as the oestrous induction factor. Ewes in both experiments were subjected to 30 min of transport by truck. In addition, oestrous behaviour and serum cortisol concentration were evaluated. Control groups consisted of un-transported ewes. In both experiments, cortisol concentration was greater (P <0·01) in transported than in un-transported animals. No difference (P> 0·05) was found between moving the ewes during pro-oestrous or di-oestrus (0·30±0·03 v. 0·53±0·18 ng/ml and 3·88±0·97 v. 2·94±0·73 ng/ml in Experiment 1 and 2 respectively). The number of ewes detected in oestrous was similar (P>0·05) among those stressed during di-oestrus, pro-oestrus or un-transported animals within each experiment (66, 47 and 42% respectively in Experiment 1 and 96·7 in all situations in Experiment 2). In general, higher cortisol concentration and more ewes displaying oestrous behaviour were detected in Experiment 2. It was concluded that under the conditions of these experiments, no difference was found in the proportion of ewes displaying oestrus regardless of the phase of the oestrous cycle in which they were transported.

Conception rate and prolificacy of dairy and crossbred goats under intensive conditions in an arid environment of northern Mexico (26° 06′ 15′′ N; maximum temperature throughout the year 12–42 °C, mean annual precipitation 186 mm, and RH <40% year-round) were examined with respect to season of mating, ambient temperature and rainfall at mating. The database contained 4194 natural services. Conception of goats inseminated with average maximum ambient temperatures >34 °C was significantly higher (P<0·01) than conception of goats inseminated when the average maximum temperature 3 days before breeding was <34 °C. The warmest season favoured conception rate (70% in spring; P<0·01) as compared to cooler seasons (62% and 64% for summer and autumn, respectively). Conception rate of goats bred when rain was present was 14 percentage points lower (P<0·01) compared to mating with no rain. When maximum temperatures on the day of mating were >34 °C, cooler temperatures 1 to 3 days before or after the day of mating were associated with a significant increase in the number of kids born. When the maximum temperature at mating was >36 °C, prolificacy for goats exposed to higher or lower temperatures 1 day before mating was 1·56 and 1·65, respectively (P<0·05). Similarly, when the maximum temperature at mating was 34–36 °C, prolificacy was higher for goats exposed to cooler temperatures as compared to warmer temperatures 1 day (1·64 v. 1·49; P<0·01) or 3 days (1·63 v. 1·48; P<0·01) after mating, with respect to the temperature on the day of mating. Conclusions were that conception rate was not compromised in non-lactating Alpine, Toggenburg, Granadino and Nubian goats subjected to high environmental temperature in an arid region, but the occurrence of rain at mating depressed breeding efficiency of these animals. Additionally, an increment in litter size is expected with cooler temperatures before or after hot days at time of mating.

Twenty-four multiparous female South African indigenous goats were used. Once a week during the 2nd (weeks 8, 11 and 14) and 3rd (weeks 18, 19 and 20) trimesters, between 08·00 and 15·00 h, four females per treatment were randomly selected and observed every 1 min for time spent grazing, browsing, ruminating and idling. Blood samples were taken once a week during the 2nd (weeks 8, 11 and 14) and 3rd (weeks 18, 19, 20 and 21) trimesters for measurements of some mineral elements and protein metabolites. Goats on natural pasture (NP) grazed 54·8 min (P<0·001) more and browsed 53 min (P<0·001) less than goats on Leucaena leucocephala-grass pasture (LGP) during the 2nd trimester. During the 3rd trimester, goats on NP treatments grazed and idled more (24·7 min, P = 0·004; 15·8 min, P = 0·044, respectively) but ruminated less (−24·1 min, P<0·001) than LGP goats. Time allotted to each field activity by the goats on both treatments within trimester seemed to be dependent on forage species composition while activity between trimesters was possibly influenced by seasons, plant type, herbage quantity, environment and quality, and changes in stage of gestation of the goats. Blood Mg level on NP was higher (P = 0·051) than on LGP during the 2nd trimester while blood Cu and albumin contents on LGP were significantly higher (P = 0·029 and 0·022, respectively) than on NP during the 3rd trimester. Furthermore, blood concentrations of the haematological parameters (except serum protein) on both treatments were within the normal range for goats in the tropics and subtropics and perhaps explain the absence of mineral and nutrient deficiency symptoms. The absence of visible symptoms of mineral deficiency and mimosine toxicity in LGP goats can be attributed to the transfer of DHP-degrading rumen bacteria. The bacteria effectively detoxified mimosine and its metabolites, thereby overcoming chelating tendency of mimosine and its metabolites. Mimosine-susceptible pregnant SAIG can be safely grazed on LGP once their rumen is completely colonized by the DHP-degrading rumen bacteria (Synergistes jonesii).

The objective of the current study was to undertake a preliminary characterization of liveweight components in adult coypus at slaughter. Greenland (14 females, 7 males) and Silver (78 females, 36 males) breeds were grown on a farm south-east of Buenos Aires, Argentina. The animals were slaughtered aged 419±22 days. Liveweight at slaughter was measured and the weights of hot carcass, fur, head, liver, lungs plus heart, digestive tract (with contents) plus reproductive organs and fur length were recorded. The weights of these body components were also expressed as proportion of liveweight, except for the fur length. Data were analysed and the effects of sex, variety, reproductive state within sex and rearing management within sex were included in the model. The age of the animals at the time of slaughter was used as covariate. Breeds differed only in liver weight (P<0·05), where Greenland was 15·9% heavier than Silver; however when comparisons were made as proportion of liveweight, no differences between breeds were found in the variables analysed. Sexual dimorphism was evident in almost all of the characteristics analysed, values for males being higher than for females. Males were 29% heavier at slaughter than females and their carcasses 31·7% heavier. When body components were expressed as proportion of liveweight, male heads were heavier but fur was lighter compared to females. In conclusion, there were differences in body components due to sex but not due to breed. However, most body components when expressed as proportion of liveweight showed no significant differences.