The effects of salt stress on the growth, nodulation and N accumulation during the vegetative phase was studied in chickpea (Cicer arietinum). Growth and N accumulation were adversely affected by salinity. The larger control plants produced new nodules but the existing nodules on stressed plants grew larger than those of control plants. All plants had similar %N contents but the total plant N was less in stressed plants due to the reduced growth of these plants. Reduced plant vigour was the primary effect of salt stress and was mediated through processes other than symbiotic N fixation.

The oestrogenic isoflavones genistein, biochanin-A and formononetin, as well as the coumestan derivative coumestrol, were identified by thin-layer, paper and gas chromatography in berseem clover (Trifolium alexandrinum) grown in Israel. Under the conditions studied, the concentration of these oestrogens in the berseem clover (total < 0·01% in the dry matter) was considerably lower than those found in clover species known to be associated with infertility in ruminants.

Sheep weighing 27 kg live weight were fed ad libitum three pelleted diets containing alkali-treated ground rice hulls (0, 5 and 15 g NaOH/100 g rice hull dry matter) in a 1:1 ratio with ground non-alkali-treated lucerne and were fed a fourth diet comprising the above control pellet fed ad libitum with a wheat grain supplement to determine the effects of alkali treatment and of energy supplementation on the digestion of cell walls and to assess the dynamics of flow of digesta through the gastrointestinal tract.

Flows of organic matter (OM) and nitrogen (N) to the duodenum were not different for the four diets, but daily whole digesta flow past the duodenum was greater (P < 0·01) for the two alkali-treated diets. Alkali treatment of rice hulls increased the percentage of total digestion of OM that occurred in the foregut (68%) compared with non-alkali-treated diets (52%), did not increase total volatile fatty acid concentration in rumen liquor, or adversely increase rumen pH. The capability of rumen microbiota to synthesize ammo acids was not adversely affected by alkali treatment. The percentage unit digestibility of cell wall constituent OM in the whole tract was increased approximately 1·6-fold by alkali treatment. Grain supplementation increased diet digestibility.

Scanning electron microscope studies revealed confirmatory visual evidence of enhanced degradation of alkali-treated rice hulls in the tract. It is clear from these studies that alkali treatment has caused sheets of silicified cuticle on the outside of rice hulls to dissolve and to lift away from the underlying lignocellulosic (palisade) matrix. It is also clear that this matrix material is itself heavily mineralized. Disappearance of silica across the gut wall was greatest for animals fed alkali-treated diets. No clinical signs of urolithiasis were seen. Sheep readily coped with the sodium intake (33 g/day) associated with alkali-treated diets, partially by an increased water consumption and a greater ruminal and intestinal absorption of this electrolyte.

It is calculated that the OM intakes recorded and nutrients released from alkalitreated rice hull diets provided between 500 and 600 kcal net energy/day.

Ground lucerne was treated with different concentrations of sodium hydroxide (NaOH) and potassium hydroxide (KOH) in a ‘dry crystal’ process, prior to pelleting.

Data for feed characteristics and related utilization by sheep fed these diets are reported. NaOH and KOH had effects of different magnitude on the digestibility of cell-wall constituents (CWC). An increase of nitrogen (N) in the cell wall (CWN) induced by tha alkali treatments, resulted in depressed nitrogen digestibility. The residual alkali and high electrolyte intakes produced higher rumen pH, but values were more stable than for sheep fed the control diet.

The effect of rainfall on dry-matter (D.M.) yield, D.M. content and crude protein (CP) content of eight barley and three wheat varieties was studied under semi-arid conditions in Cyprus for 5 years. The best variety was 628 barley, which gave the highest mean yields (6·7 and 0·69 t/ha of D.M. and CP respectively), showed the highest response to annual rainfall (33 g D.M./mm rainfall) and gave high yields in all environments, D.M. yield was not affected significantly by earliness but late varieties had higher D.M. and lower CP contents than early varieties. All varieties showed around average stability. Regression coefficients between D.M. yield and mean yield of varieties for all environments ranged from 0·81 to 1·14 and were not related to D.M. yield of varieties.

The fraction of the variation in D.M. yield explained by the variation in annual rainfall varied with variety from 25% to 67%. Multiple regression analysis using the annual rainfall and the rainfall 1 and 2 months before harvesting produced a slightly, but not significantly, higher correlation over the simple correlation between D.M. yield and annual rainfall. Varietal response to annual rainfall, as expressed by the regression coefficient between D.M. yield and annual rainfall, was positively related to D.M. yield (r = 0·84, P < 0·01).

The correlation coefficients between D.M. content and annual rainfall ranged from −0·46 to −0·92 while that of CP content and annual rainfall, though not significant in most cases, also tended to be negative.

The body composition of 24 pigs reared at different rates of growth from 25 kg live weight was estimated when they each weighed about 90 kg live weight. Feed conversion corrected for the energy requirements of maintenance (CFCR), external and ultrasonic measurements, and measurements of Evans Blue, deuterium oxide and potassium-42 were applied simultaneously to each pig, and were used to predict the weights of the fat-free mass, lipid, and dissectible fat and lean.

The best individual predictors of body composition were CFCR, deuterium oxide and potassium-42, but Evans Blue, external and ultrasonic measurements were not as closely associated with the four body components.

In combination, it was generally found that two predictors could predict the weight of a body component more closely than either predictor in isolation.

An experiment was designed to investigate the effect of a sustained lactation pattern on the intake of milk or solid food by lambs and on their consequent growth rate. Normal lactation pattern was compared with sustained lactation, achieved by fostering lambs at 24 days of age on to newly-lambed nurse ewes. Two genotypes of lamb were used; these were pure-bred Scottish Blackface and Textel × Blackface. Lambs were offered one of two qualities of pelleted concentrate food from 4 weeks of age.

Maximum daily intakes of milk were 2·16 and 1·87 kg/day, respectively, for fostered and non-fostered lambs. This differential was maintained until the 10th week. Pattern of lactation had no significant effect on total energy intake from milk and solid food combined or on live-weight gain up to 10 weeks of age. Texel cross lambs consumed more food than did pure Blackface lambs and showed correspondingly higher rates of live-weight gain. Lambs ate slightly more of the higher quality pellets than the lower but there was no effect of solid food quality on milk intake. Within breed of lamb there was a negative relationship between intake of milk and of solid food.

Inbred lines and hybrids of English tick and horse beans and exotic stocks were studied with respect to pod set, floral structure and pollen production and germination to find out why most inbred lines set few or no seeds without tripping whereas most hybrids and some inbred lines set equally well with or without tripping. The most important outcome was new information on variation between genotypes in flower structure and pollen quantity and on how these two characters affect the mechanics of self-pollination. Though heterosis in terms of abundant pollen production could be a factor in the self-pollinating ability of hybrids, some of the inbred lines were capable of self pollination despite limited pollen production, because the structure of the flower permitted the pollen to reach the stigma via a short route. The floral features associated with the ability to self-pollinate in the inbred lines included a relatively short style bending at more or less a right angle, few and short stylar hairs and stigmatic papillae, and less pronounced ridges on the inside of the keel petals. The implications of these findings to the development of self-pollin ated varieties of field beans are briefly discussed.

The rate of evaporative water loss has been studied in domestic fowls in the ambient temperature range from 0 to 40°C.

Results for whole-body evaporation were similar when obtained by the open-flow and direct-weighing methods. At low levels of absolute humidity the rate increased by 0·03 mg/(g.h.°C) from 0 to 22 °C and by 0·17 mg/(g.h.°C) from 23 to 40 °C. Wholebody evaporation decreased with rising ambient water vapour pressure by 0·7 mg/(g.h.kPa).

Cutaneous water loss was greater than respiratory water loss below 21 °C; it accounted for 78% of whole-body evaporation at 0 °C, falling to 25% at 40 °C.

The rates of respiratory and whole-body evaporation could both be expressed as linear functions of respiratory frequency.

Dissection data for 753 steer carcasses comprising 17 breed-type × feeding system groups were used to examine the distribution of lean between 14 standardized commercial joints. Breed types included Ayrshire, Friesian, Friesian × Ayrshire and crosses out of Friesians by Angus, Charolais, Hereford, Limousin, Simmental and South Devon sires. Most cattle were grown on cereal or grass/cereal systems of feeding. Group means for weight of lean in the side (half carcass) ranged from 60·0 to 85·2 kg with a pooled within-group S.D. of 7·81 kg.

The increase in lean weight in each joint relative to that in the side was examined using the allometric equation. Pooled within-group growth coefficients (b values) indicated that relative lean tissue growth was lowest in the leg (hind shin) and rump (b = 0·84 ± 0·03 and 0·85 ± 0·03 respectively) and highest in the clod and sticking (b = 1·19 ±0·03). The result for the combined higher-priced joints was 0·95 ±0·01.

The pooled growth coefficients were used to adjust the weight of lean in each joint to equal total lean weight in the side where this was legitimate. Statistically significant (P < 0·001) but relatively small differences were recorded between groups in the adjusted means for all joints tested. At equal total lean weight, Charolais × Friesian, Limousin × Friesian and Simmental ×; Friesian groups had the highest weight of lean in the combined higher-priced joints and the Ayrshire and Friesian × Ayrshire groups the lowest. The difference between the two extreme groups was 2·1 kg (for one side).

A standardized impregnated filter-paper bioassay technique was specially developed for screening insecticides against adults of the whitefly Bemisia tabaci Genn. (Homoptera, Aleyrodidae). It was found that the most suitable exposure period, after which mortality counts should be made, was 11·7 ± 2·1 h. Two different techniques for applying the insecticide solutions to the filter paper disks were tested and verified.

Seventy-four field experiments on the nitrogen requirement of sugar beet were made in eastern England in. 1966 to 1974. Considerable differences in sugar yield response to nitrogen were found between the six soil types used, and these differences were found (on five of the six soils) to be related to sugar yield. Nitrogen response was large on chalk and limestone soils in Lincolnshire, intermediate on East Anglian boulder clays and least on East Anglian chalk and light drift soils. On the lighter soils (limestones, East Anglian chalks and light drifts) nitrogen response was greater with high summer rainfall than with low. Fenland silt soils were very high yielding, but nitrogen response was moderate.

Optimum nitrogen rates differed between soils, in the range 100 kg/ha on East Anglian chalks and light drifts to 180–200 kg/ha on Lincolnshire chalks and limestones.

Three field experiments were carried out on sandy loam soil at Levington, Suffolk, on the effect of irrigation on nitrogen requirements of sugar beet. Four nitrogen rates (0, 67, 134, 201 kg/ha) were examined with and without irrigation. Nitrogen increased sugar yield each year, as did irrigation in 1969 and 1970, but not in 1968 when the soil moisture deficit was small. There was a significant nitrogen x irrigation interaction in 1970 only, but on average there was a greater response to nitrogen with irrigation than without it.

These results and other published data suggest that on sandy soils in eastern England moisture deficit can restrict nitrogen response, and that the economic optimum nitrogen rate is appreciably higher with irrigation than without it.

A basal diet, or the basal diet supplemented with equi-nitrogenous amounts of either ammonium lactate, ammonium acetate or urea was fed to four re-entrant cannulated sheep in a randomized block design.

Collections of duodenal digesta were carried out automatically for a continuous period of 4 days following a 10-day equilibration period for each sheep on each diet.

Supplementation with non-protein nitrogen increased the passage of total amino acids to the duodenum and increased the proportion attributed to microbial protein. It improved pre-duodenal digestibility of modified acid-detergent fibre and increased post-abomasal digestibility of non-ammonia nitrogen, dry matter and gross energy.

Supplementation with non-protein nitrogen increased the energetic efficiency of microbial protein production in the rumen.

Ammonium lactate and acetate were safe and effective sources of non-protein nitrogen for dietary supplementation.

Supplementation with ammonium lactate led to a greater passage of microbial protein to the duodenum than did equi-nitrogenous supplements of urea or ammonium acetate.

Mature green plantains (Bini variety) dipped in fungicide and stored with Purafil in polyethylene bags, remained green and hard for 3–4 weeks before ripening started. Fruits stored with Purafil or potassium permanganate kept longer (by 2 weeks) than those stored with potassium iodate or potassium dichromate. Severe chemical and fungal damage occurred in fruits stored with calcium hypochlorite, indicating that plantain fruits may be sensitive to chlorine. No significant difference in storage life was observed between fruits stored in polyethylene bags alone and those stored in potassium iodate or potassium dichromate. There was much lower incidence of fungal infection in fruits dipped in thiabendazole (1 g/l) than those dipped in Diathane M45 (3 g/1). Fruits dipped in thiabendazole before storage remained virtually free of fungal attack even after they had completely ripened.

Information is given on dates of sowing and mid-silk for Inra 200 in 40 experiments (two each year at Oxford, 1962–75, and at Cambridge, 1970–5), together with cumulative temperatures between these dates. Two methods of defining effective temperature for maize development have been considered, namely the method advocated by U.K. Meteorological Office with 10 °C as the base temperature (the Ag. Met. method) and that defined in Ontario units. The regression relation between accumulated temperature and dry-matter content of the grain during ripening has also been calculated, from data obtained in the years 1966–74, and assessments made of cumulative totals in Ag. Met. day °C and in Ontario units from the date of silking until the grain D.M. content is 40%, when the crop is considered suitable for ensiling, and from silking until grain D.M. content is 60%, when the crop may be considered ripe.

Cumulative temperature totals were significantly more stable over experiments than time expressed in calendar days. Totals of Ontario units were less variable than totals of Ag. Met. day °C. Estimated requirements for Inra 200 were 405 day °C or 1380 Ontario units from sowing to mid-silk, 255 day °C or 800 Ontario units from silking to 40% D.M. in the grain (for silage crops), and 380 day °C or 1235 Ontario units from silking to 60% D.M. in the grain.

The uptake efficiency of roots for sulphate and potassium was evaluated in wheat, sugar beet, and tomato, at different ploidy levels. At increasing ploidy, wheat and sugar beet showed higher, tomato lower efficiency, the polyploid absorption system being characterized in sugar beet by higher Vmax and Km, in wheat by higher Vmax and unchanged Km, in tomato by lower Vmax and Km. Uptake efficiency of roots appears tightly bound to the evolutionary progress, that is to the level of environment adaptation of plants, and should be susceptible of further improvement by breeding practices.

A winter barley variety, from the USSR, 13031, lacking vernalization requirement but sensitive to short days and more frost resistant than varieties now commercially grown in Britain, was hybridized with Shimabara, a Japanese variety which requires vernalization but is less sensitive to short days and more susceptible to frost than 13031. The resulting segregating population was then selected under short days and non-vernalizing conditions and in artificial freezing tests, in order to isolate recombinant lines.

Five lines derived in this way, together with the parents and the standard winter barley variety, Maris Otter, were included in a detailed developmental study made in a glasshouse under cool, short days.

Four of the lines had very similar developmental characters, namely few leaves and a high rate but short duration of spikelet initiation. Developmentally these selections resembled the parent Shimabara more closely than 13031 but the rate of spikelet initiation was faster than that of either parent and the duration of spikelet initiation was shorter. The fifth selection also resembled Shimabara more closely than 13031 but had more leaves and a lower rate and longer duration of spikelet initiation than the other selections. This selection was found to have a strong vernalization requirement.

One selection closely resembled 13031 in its frost resistance but had low short-day sensitivity and no detectable vernalization requirement. The complementary characters of the two parents were therefore recombined in this line.

Vernalization had little effect on the development of any of the genotypes under cool, short days in a glasshouse.

Five levels of frozen grass and heather (Calluna vulgaris, L. Hull) which contained 85% of the current season's shoots, were offered to five castrated male Scottish Blackface sheep per level. The levels of grass were 0, 200, 400, 600 and 800 g D.M./day, and heather was offered ad libitum after the grass had been eaten. Both the grass and heather were harvested in September. Voluntary intakes of heather increased by 0·46 g/g of additional organic matter intake (OMI) of grass between the two lowest levels of grass, but at higher levels of grass there was a highly significant (P < 0·001) linear decrease in OMI of heather of 0·57 g/g additional OMI of grass.

No associative effects of grass (OM digestibility 70%) and heather (OM digestibility 44%) on OM or neutral-detergent fibre digestibility could be demonstrated. Intakes of digestible OM and nitrogen balance increased in a positive and linear manner with the proportion of grass in the diet. To meet the nitrogen and energy requirements for maintenance of the sheep the diet would require to contain 50% of grass. These findings are discussed in relation to the nutrition of sheep grazing heather-dominant moorlands.

A comparison was made between an intensive system of lamb production based on Italian ryegrass RvP and one based on perennial ryegrass S. 24, over 2 years, each at three stocking rates (14, 17, 20 ewes/ha). More grass was grown in the first year than in the second when the yield of RvP was particularly reduced. The ewes and lambs ate more RvP than S. 24 but there was no difference in lamb growth rate. The lambs grew faster at the low stocking rate from 0 to 18 weeks and from 0 to slaughter than at the medium and high stocking rates, in both years. Ewe intake and lamb growth rate were higher in the second year than the first. The Masham ewes with two lambs ate significantly more grass per unit of body weight than the Finnish Landrace × Scottish Halfbred and Finnish Landrace × Scottish Blackface ewes, and their lambs grew significantly faster. It was concluded that for an intensive system of lamb production from grass, S. 24 was more suitable than RvP.