The goals of this study are to analyse the impacts of 1.5 and 2.0°C scenarios on UK winter wheat using a combination of Global Climate Models (GCMs), crop models, planting dates and cultivars; to evaluate the impact of increased air temperature on winter wheat phenology and potential yield; to quantify the underlying uncertainties due to the multiple sources of variability introduced by climate scenarios, crop models and agronomic management. The data used to calibrate and evaluate three crop models were obtained from a field experiment with two irrigation amounts and two wheat cultivars that have different phenology and growth habit. After calibration, the model was applied to fifty locations across the wheat-growing area of the UK to cover all the main growing regions, with most points located in the main growing areas. Four GCMs, with two cultivars and five planting dates, were simulated at the end of the century. Results of this study showed that the UK potential wheat yield will increase by 2–8% under projected climate. Farmers will need to close such a gap in the future because it will have implications in terms of food security. Future climatic conditions might increase such a gap. Adaptation measures (e.g. moving the optimal planting time), along with climate-ready varieties bred for future conditions and with precision agriculture techniques can help to reduce this gap and ensure that the future actual UK wheat production will be close to the potential.

In a previous paper Quinlan(1) published the results of his observations on a flock of sheep which had been vasectomised for two years. The present paper contains a résumé of the data already published, to which an additional twelve months' observations have been added. This paper gives the data available from observations carried out on the flock over a period covering three years, or a period of time which allowed full skeletal development to take place.

The absorption and translocation of phosphate by roots of intact seedlings of rape, oats, flax and buckwheat were studied. Two hydroponic experiments were conducted in the greenhouse. A split-root technique was used in which a single root of the culture plants was grown in one solution and the rest of the roots in another solution in a twocompartmented glass jar.

The presence of other nutrients had a favourable effect on root growth and was essential for efficient phosphate absorption. There was a positive relation between the extent of root growth and phosphorus uptake. On the basis of unit weights of a single root, rape was not any better than oats and buckwheat. A single root of rape, in the presence of other nutrients, absorbed two-thirds of the phosphorus absorbed by all the other roots, whereas single roots of buckwheat, oats, and flax were much less efficient than the rest of the roots. In the absence of other nutrients, single roots of buckwheat, rape and oats absorbed 4·61, 0·18 and 3·49%, respectively, of the phosphorus supplied. However, in the presence of other nutrients, the corresponding values were 21·68, 43·86, and 7·62%, respectively. Both in the presence and absence of other nutrients the single root of flax did not absorb phosphorus from solutions high in phosphate. The results indicate that the age of the plant has an important bearing on the uptake and translocation of phosphorus.

1. The fungicidal properties of solutions containing sulphur in polysulphide form, viz. sodium, potassium, calcium and barium polysulphides, were tested by application to the conidial stage of Sphaerotheca Humuli growing upon young hop leaves in the greenhouse.

2. Four samples of sodium polysulphide solutions, two prepared in the laboratory and two commercial products, were examined. When applied with 1 per cent. soft soap as the spreader, solutions containing 0·5 per cent. polysulphide sulphur proved fungicidal. With 0·5 per cent. gelatine as the spreader, fungicidal strength did not begin to be attained until the concentration of polysulphide sulphur reached 0·11 per cent. The results suggest that the nature of the spreader may influence the fungicidal properties of polysulphide sulphur.

White clover cultivars Sacramento ladino, Sonja and Aberystwyth S.184 were assessed for dry matter (DM) yields, clover content and herbage quality in monostand and in 50:50 mixtures with grasses under cutting at Truro, Nova Scotia and Charlottetown, Prince Edward Island between 1986 and 1989. Grasses were: orchardgrass (Dactylis glomerata L.), tall fescue (Festuca arundinacea Schreb.), timothy (Phleum pratense L.) and reed canarygrass (Phalaris arundinacea L.). Dry matter yields ranged from 6158 to 11645 kg/ha and were highest in white clover/orchardgrass and white clover/timothy at Truro, and in white clover/timothy at Charlottetown. Sonja and Aberystwyth S.I84 outperformed Sacramento white clover in herbage DM and clover yield in all years at both locations. First-cut herbage contributed 39 and 29% of total yields at Truro and Charlottetown, respectively. Clover yield was highest in first-cut Sacramento/orchardgrass, but dropped by up to 73% in white clover/timothy associations over a 2-year period. Crude protein ranged from 14·4% in clover/timothy to 23·4% in clover/reed canarygrass and was positively correlated with clover content. It was concluded that choice of clover cultivar as well as grass is an important consideration in maximizing herbage yields and quality in the Atlantic region.

Two experiments were conducted to study the influence of heat treatment of Vicia faba beans on the productive performance of laying hens fed diets containing large proportions of the beans. In the first experiment, the effects of extruding and pelleting the beans were studied while in the second experiment the effects of autoclaving at 121 °C for 30 min the cotyledons and hulls of the beans were evaluated. Hyline-W36 layers were used in the first experiment while two strains (Shaver-288 and Dekalb) of birds were used in the second experiment. Each experiment lasted 5 months during which data on egg production, egg weight, feed intake, mortality and body-weight gain of birds were collected. The results obtained indicated that heat treatment (extruding, pelleting and autoclaving) of the beans, cotyledons and hulls had no beneficial effect on the productive performance of laying hens fed on diets containing large proportions of the heated beans, cotyledons and hulls. Egg-size reducing factors appeared to be concentrated in the cotyledons rather than the hulls of the beans.

S1 maize varieties and varietal hybrids were tested in six locations ranging in altitude from 236 to 1600 m in Cameroon. The grain yields of highland varieties were observed to increase with each increase in altitude while the yields of the lowland varieties decreased with increasing altitude.

The highland × lowland S1 varietal crosses yielded the same as the lowland parental varieties in highland areas and better than highland parental varieties in lowland areas.

Average yields of all varieties per location increased by about 1·1 t/km increase in altitude. Eberhart & Russell's (1966) stability method found no stable variety while Francis & Kannenberg's (1978) genotype-grouping technique found five highland × lowland crosses to be relatively stable.

Number of days from planting to tasselling increased with increasing altitude by about 20 days/km increase in altitude. Highland and lowland varieties performed poorly outside their zones of adaptation because of high incidence of foliar diseases like leaf blights and rusts.

Cassia acutifolia Del., known in the Sudan as ‘Senna Makka’ and in commerce as ‘Alexandrian Senna’ (Tothill, 1948), is indigenous to the Sudan and grows wild in the Northern and Central Provinces. It is used locally as a laxative and itsactive ingredient senoside is extracted for pharmaceutical purposes in England, U.S.A. and Germany. The Sudan has been exporting pods and leaves of Senna for many years and the crop has been steadily growing in economic importance. The exported produce is obtained from wild or cultivated Senna plants. Recently a breeding programme has been initiated to provide improved varieties that can both meet the growers’ need for high yield and satisfy the market's demand for uniform high quality produce. Before a proper plant breeding programme can be established, the mode of reproduction must be known since crop breeding procedures are largely determined by the reproductive system. This paper reports on studies made to determine the breeding system in Alexandrian Senna.

1. Radioactive phosphorus was injected into young sheep that had been fed diets low in either phosphorus, phosphorus and vitamin D or calcium. Forty-eight hours after the injection the animals were killed and samples of bone and teeth were removed for specific activity determinations.

2. The specific activities of bone varied according to the site from which it was taken, but in general a strong inverse relationship was found between specific activity and the quality of the skeleton.

3. In teeth that were formed during the period the diets deficient in phosphorus or phosphorus and vitamin D were fed, the specific activities of the dentine and enamel were greater than for corresponding tissues from the control animals.

In soil moderately infested with potato golden cyst-nematode, Globodera rostochiensis, nematicide treatments which lessened soil infestation when a susceptible potato crop was grown permitted a satisfactory second crop to be grown 3 years later without further treatment. In two experiments on heavily infested sandy loam on the same farm (Woburn Experimental Farm, Bedfordshire), aldicarb or oxamyl, incorporated in the seedbed in 1979 or 1980, greatly increased yields of Pentland Crown tubers and reduced the number of eggs left in the soil after harvest, but had little effect on a second crop of Pentland Crown potatoes grown 4 years later. Application of aldicarb or oxamyl to the seedbed before this second crop of potatoes increased yields and lessened nematode increase. The injection of 1,3-dichloropropene mixture (Telone II) into the soil in autumn at 224 kg/ha in one of these experiments did not enhance the nematode population control achieved by aldicarb or oxamyl alone.

A total of 886 cows of two herds belonging to the Ministry of Agriculture, Egypt, were used in this study to investigate the effects of inbreeding and cross-breeding on dairy traits. The first herd consisted of the native breed Domiatty (D), Shorthorn (S) and different grades between them while the second of Jersey (J) and its different crosses with D. There were 1027 lactations from the first herd and 460 from the second. Inbreeding coefficient (F) averaged 0·06 in the first herd and 0·08 in the second, both ranging from 0·00 to 0·30. The range was partitioned into three classes: the first with 0·0 ≤ F ≤ 0·1, the second 0·1 ≤ F ≤ 0·2 and the third F ≥ 0·2. Traits studied were first and second lactation 305-day milk yields, age at first calving, first calving interval and first dry period.

Inbreeding had no statistically significant effect on any of the traits except dry period in the first herd. Inbreeding was not associated with decrease in yield when F ≤ 0·2 in the first herd, while there was consistent decrease with inbreeding in the second herd. No clear trend could be observed on the effect of inbreeding on any of the other traits in the first herd whereas in the second the rise in inbreeding was always associated with greater age at first calving, with wider calving interval and with longer dry period.

Experiments at Sutton Bonington in 1973 and 1974 compared the growth and yield of sugar beet which was handweeded at different stages with that where weed control was entirely by pre- and post-emergence herbicides, used alone and in various combinations. Data from the series of handweeding treatments enabled the crop's minimum weed control requirements to be specified. They indicated that an ideal herbicide would kill all the weeds present when applied at the six-leaf stage, persist in the soil to prevent weed infestation for 4 weeks, but not check the crop to the extent that recovery was incomplete. That the crop was capable of recovering from a degree of early check was clearly evident from the handweeded treatments; it proved possible for crops whose weights had been depressed by 25–30 % when first weeded to recover completely by harvest.

The performance of all post-emergence treatments fell short of these requirements. When the crop was at the six-leaf stage, the earliest emerging weeds were too far advanced to be killed by the herbicide. By themselves, pre-emergence herbicides gave weed control equivalent to only 2 or 3 weeks of handweeding but they did pave the way for more effective use of post-emergence treatments by restricting the spectrum of weed sizes present and sensitizing those plants which did establish. The most effective herbicide regime used in the experiments was the sequence of chloridazon applied pre-emergence followed by two post-emergence applications of phenmedipham. However, phenmedipham clearly checked the crop. Two weeks after application crop dry weight was usually depressed by one-third. Provided weed control was adequate, recovery was usually complete by the end of the season.

1. Protein in wheat is the most important constituent, and therefore the chief constituent to breed for. No wheat variety possesses at once combined the desired characteristics of high protein, high yield, maximum flour production, and maximum bushel weight.

2. So far as climatic factors are concerned, a short, comparatively dry growing season, especially in the spring, in the case of winter wheat, favours the development of grain rich in gluten, and hence high in protein.

3. The most important ground factor in determining the starchprotein ratio is the water supply. The protein content has been found to vary from 11·63 per cent, under 22–24 inches of rainfall to 14·93 per cent, under 12–13 inches (Minnesota); and from 12·63 per cent, under 25 inches of irrigation to 13·62 per cent, under no irrigation (Utah).

Carcass weight, bone weight, bone length, and bone weight per unit length were examined as possible indices of the weight of muscular tissue in lamb and mutton carcasses.

In cases of anaemia in cattle and sheep, of infectious origin, parasitic origin, or due to simple haemorrhage, the phosphorus partition of the blood reveals an “unknown fraction,” confined to the corpuscles, and evidently nucleoprotein. It is determined by difference between the total phosphorus and the sum of total acid-soluble and lipoid phosphorus. It is associated with the appearance of nucleated red cells (normoblasts and Jolly bodies) and vanishes as they disappear. The amount may make up a considerable proportion of the total P.

A field experiment was carried out on soyabean (Glycine max (L.) Merr.) to measure the effect of planting date (soil temperature) on seedling emergence. Seeds were sown at weekly intervals on seven planting dates from April until the end of May in SE England in 1997. Planting date had no significant effect on final percentage emergence but had a highly significant effect on time to emergence. The coefficients of variation (c.v.) for the number of days to emergence (calendar days) were high (43–45%), and therefore not a reliable method for predicting emergence. Three accumulated heat unit (AHU) methods based on air and soil temperatures were compared with the calendar day method to determine the most reliable system for predicting seedling emergence. Accumulated soil temperatures above a base of 9·0 °C had the lowest c.v.s (8–15%) and were shown to be the most reliable predictor of emergence.

The response of two cultivars of dry harvest field peas (Pisum sativum), Solara and Bohatyr, to irrigation at different growth stages was studied on light soils overlying sand in Nottinghamshire, England in 1990, when the spring was particularly dry, in 1991 which had a dry spring and summer and in contrast, 1992, when rainfall was greater compared with the long-term (40 year) mean.

Solara, short haulmed and semi-leafless was more sensitive to drought than the tall conventional-leaved cultivar Bohatyr and gave a greater yield response to irrigation, particularly at the vegetative growth stage in the first two dry years 1990 and 1991, of 108% and 55% respectively, compared with unirrigated plots. Bohatyr was less sensitive to the timing of single applications.

In all years, peas irrigated throughout on several occasions produced the highest yields, but this was the least efficient use of water.

Heat stress, especially in countries with hot climates, is a major cause of low fertility in high-producing dairy herds. Management strategies are needed to help producers improve the reproductive performance of their dairy animals under such conditions. The current study aims to evaluate the effects of pre- and post-milking insemination on the conception rate (CR) in dairy cows. The dataset included 1294 insemination records leading to pregnancy in 708 lactating Holstein dairy cows. The GLIMMIX model procedure of SAS based on the generalized linear mixed model methodology was used to analyse the results of insemination (success or failure) as a binomial distribution with the logit link function. Differences were observed in CRs between pre- and post-milking insemination. The pregnancy odds ratio (OR) for post-milking insemination relative to that for pre-milking one was estimated at 1.90 [1.23‒2.91; 95% confidence interval (CI)]. Different levels of interaction were obtained between average daily milk production and time of insemination. In the high-producing group, the pregnancy OR for the post-milking relative to that for the pre-milking insemination was estimated at 3.53 (2.00‒6.24; 95% CI). A significant interaction effect was obtained between insemination time and the temperature-humidity index. A pregnancy OR of 2.52 (1.22‒4.14; 95% CI) was recorded for the cows inseminated after milking on days with higher levels of heat and humidity stress v. the pre-milking inseminated ones. Based on the results, post-milking insemination of high-producing cows increased CRs, especially on days with high heat and humidity stress.