Two populations, one non-improved of Dactylis glomerata and one improved of Agropyron cristatum were selected in an isolated spaced plant environment (80 cm) by three selection procedures: (1) Mass honeycomb selection (MHS), (2) pedigree honeycomb selection (PHS) and (3) pedigree honeycomb selection-combined criterion (PHS-CC). The third procedure is a between-families selection based on increased family mean and reduced family coefficient of variation (CV). Response to selection assessed in sward trials in the first and second harvest year was effective for the three procedures, which ranked PHS-CC > PHS > MHS. Evaluation was based on consistent efficiency as measured by both cloned and half-sib families. The precision of assessing progeny performance under sward conditions on the basis of single plant evaluation in the isolation environment, increased with a reduction in competition among plants, the use of moving-ring selection, and the application of high selection pressures (1·6%). The efficiency of selection between unimproved families increased when families were selected concurrently for high family mean and reduced family coefficient of variation.

Seventeen gnotobiotic lambs were reared up to 21 weeks of age on cows’ milk followed by sterile solid diets similar to diets fed to conventional lambs. Seven were given limited defined populations of rumen bacteria, seven were left uninoculated and three were dosed with rumen contents from conventional sheep (‘conventionalized’). The lambs were reared in four groups corresponding to four lambing seasons.

Gnotobiotic lambs fed cows’ milk ad libitumgrew at similar rates and converted feed into live-weight gain with similar efficiency to conventional lambs. The gnotobiotic lambs irrespective of inoculation and the two conventionalized lambs in the first three groups failed to maintain growth on solid diets when milk feeding had been stopped. However, three gnotobiotic lambs in the fourth group, two of which were inoculated, continued to grow satisfactorily for at least 6 weeks on a solid diet alone, and the inoculation of defined populations of bacteria appeared to confer an advantage. The conventionalized lamb in the fourth group suffered a severe temporary setback, following which it grew well.

In experiments with maincrop potatoes at Rothamsted in 1976, 1977 and 1978 ‘Nitro-Chalk’ was broadcast, either as a single dressing on the seed bed, or half on the seed bed and half at tuber initiation. Isobutylidene di-urea was broadcast on the seed bed and aqueous ammonia was injected into the seed bed, without a nitrification inhibitor or with either ‘N-Serve’ (nitrapyrin) or sodium trithiocarbonate; all were compared with ‘Nitro-Chalk’ at rates of 200 or 300 kg N/ha. Additionally, single dressings of ‘Nitro-Chalk’ supplied 150, 250, 350 and 400 kg N/ha. In similar experiments at Woburn in 1979 and 1980 aqueous urea replaced aqueous ammonia and the additional amounts of ‘Nitro-Chalk’ (100 and 400 kg N/ha) were tested as both single and divided dressings. Winter wheat was grown in each of the following years to measure residual effects.

Retaining half of the total N dressing of 200 or 300 kg N/ha as ‘Nitro-Chalk’ until tuber initiation improved yields at Rothamsted in 1976 and 1978 when irrigation was applied but not in 1977 when it was not. Dividing the N at Woburn improved yields at 100 and 400 kg N/ha but not at 200 or 300 kg N/ha. At Rothamsted injected aqueous ammonia was on average similar in effect to the undivided ‘Nitro-Chalk’ dressing at 300 kg N/ha, but less effective at 200 kg N/ha. In 1977, the wettest summer, it was, however, the most effective of the N-sources, provided that an inhibitor had been applied with it. At Woburn, injected aqueous urea did not differ consistently in effectiveness from ‘Nitro-Chalk’ and inhibitors did not improve its performance. Isobutylidene di-urea (IBDU) gave the smallest yields at both farms, apparently because it was too slowly available. Tuber size distributions were affected little by the amount or the form of N.

IBDU residues increased wheat yields the most following the potatoes at Rothamsted. This apart, the N-sources had similar residual values.

Five potato varieties were grown at four sites over 2 years, and assessed for yield, specific gravity and for sloughing, texture and discoloration following steaming. Variation in discoloration was attributed to differences between sites. Genetic differences were established for specific gravity, sloughing and texture, all of which were positively correlated. Genotype × environment interactions and years × sites interactions contributed to the variation for these and the remaining variables.

Botrytis allii, grey mould, is the major cause of bulb and seed yield losses of growing onion seeds in Israel. Nursery treatments with iprodione or vinclozolin significantly decreased the number of diseased onion bulbs which were supplied to the farmers from 24% in the control to 8% in the treated plots and resulted in higher yield of seed with increases of 45% in seed weight per plant. Onion bulbs under non-irrigated conditions in the mountains were found to be more susceptible to the disease, as well as to secondary infection, than irrigated onions that were grown in the plains. Chemical treatment of the bulbs before planting significantly reduced the rate of secondary infection in the field and decreased seed losses. The survival of B. allii propagules and their importance as a primary source of inoculum in growing onions for seed were studied in the central mountainous region of Israel. From 197 to 1532 B. allii propagules per g soil were found in the field plots, this as the result of only one season growing onion seed. Ninety-one per cent of the total planted healthy bulbs were infected in the highly contaminated plots after 150 growing days. The surviving B. allii propagules reduced the seed yield, from 14·4 in the less contaminated plots to 10·4 g/plant in the highly contaminated.

The quantity of in vitro digested cell wall was determined in the separated leaf and stem of Digitaria decumbens (pangola grass) fertilized at three different levels of nitrogen and cut after two different periods of regrowth. The treatment means ranged from 39·6 to 41·5 g digested cell wall per 100 g forage organic matter in leaf, and from 37·5 to 41·6 g in stem. For both leaf and stem the lowest mean amounts of digested cell wall were associated with the highest levels of fertilizer and the longer periods of regrowth. The results for nitrogen fertilizer were consistent with those from previous in vivo digestibility experiments, but when the effect of the total cell wall on digested cell wall was taken into account there were inconsistencies. The previous in vivo digestibility data were used in conjunction with the present results in support of a view that interpretation of digestibility data for grasses is best made by reference to a constant digested cell wall of 39·5 g/100 g forage organic matter.

1. Italian ryegrass was used in 1958 and in 1959 to compare ‘single’ spring dressings of urea-formaldehyde fertilizer (UF) with equivalent spring dressings of ‘Nitro-Chalk’ (NC), and with ‘repeated’ NC (divided equally between three cuttings). Barley measured residues in 1960.

2. At the first cut each year, yields from UF and repeated NC were similar, but later NC gave much larger yields. Aggregate increases from UF were less than half those from equivalent NC.

3. Both forma of nitrogen had residual value for grass and barley.

4. Maximum recovery of N, over 3 years, was 54% for UF and 90% for equivalent NC. Single NC dressings were recovered more completely than repeated dressings.

5. The maximum aggregate uptakes over 2 years by grass receiving 2·0 cwt. N/acre each year were 72 lb. P and 611 lb. K/acre.

A series of upwards of 6000 matings of goats has been arranged according t o the month of service and correlated with temperature and rainfall.

The maximum of reproduction is found to be in October, and the minimum in May.

A cool summer produces early oestrus while a hot one has the opposite effect. The August temperature is of paramount importance in this respect.

Rainfall had no effect, on the onset of oestrus in the series examined.

The hypothesis is advanced that most mammals breed only in the spring and autumn because their body temperature may be too high in summer for follicular development.

Free amino -N estimations were used to monitor the movement of amino acids in the vascular system of sheep. The net uptake of free amino-N by portal drained viscera was measured in whole blood and compared with the net gain in the plasma flow.

In normally fed sheep eating dried grass, lucerne or silage the net gain of free amino -N in the plasma of portal blood contributed less than 80% to the total uptake in whole blood. When the protein component of the diet was added into the abomasum (casein supplement to a low nitrogen basal ration) the plasma contribution to the net gain in portal blood averaged 95%.

The results suggest that the cells as well as the plasma are involved in the transport of amino acids in blood and that in ruminants all amino acids have to be measured in blood for a quantitative calculation of the absorption from portal drained viscera.

Twelve genotypes of cauliflower were grown in two seasons from six seedling propagation treatments in three sequential sowings. There was a high genotypic component of variation for curd weight, indicating that this character can be improved by breeding. A large genotype × environment interaction included genotypic differences in stability to the environment, notably in the self-compatible genotypes. Mean curd weight and stability of genotypes to the environment for this trait were uncorrelated, indicating that high weight and high stability could be bred into a single variety.

1. The electrical conductivity of aqueous extracts of soils, in the proportion of one of soil to five of water, varies according to the time of extraction. In the more fertile soils extraction for three to four hours gives less than half as great a conductivity as is given in 4 to 11 days.

2. In peat the maximum value is reached almost at once, the extract having a high conductivity. The maximum value is also reached quickly in certain infertile soils, which give an extract of very low conductivity, closely similar to that of the purest upland streams.

3. A high electrical conductivity in the extract may only indicate the presence of an excess of salts, and does not necessarily indicate a good soil. It seems, however, that a rapid increase in conductivity as extraction is prolonged indicates increased solubility, partly through bacterial action and may be considered as a useful indication of fertility. A low conductivity, which remains low on continued extraction, denotes a soil so insoluble as to be unfertile.

The variability revealed in a half-diallel cross between nine diverse genotypes of winged bean (Psophocarpus tetragonolobus (L.) D.C.) in regard to yield and yield components was studied in the F1 generation. The results indicated that high genetic variability existed for all traits. With respect to seed size, general combining ability effects alone were adequate to predict the performance of hybrids. For numbers of pods per plant and seeds per pod, both general and specific combining ability effects were of equal importance, while the performance of hybrids for grain yield was mainly dependent on specific combining ability effects. Heterosis was clearly evident for number of seeds per pod and grain yield. Of the yield components, number of pods per plant exhibited a positive genotypic association of appreciable magnitude with grain yield, showing its usefulness as an indicator of yield in selection.

Under perennial grasslands, nitrogen contained in organic matter becomes available at varying rates via mineralization throughout the growing season. The amount of N present at any given time indicates only the quantity immediately present, and does not include N which has already been removed either by leaching or uptake into the plant system, nor the N which will become available as organic matter breaks down over time. Long-term aerobic laboratory incubation methods have been used successfully to estimate potential N mineralization under various cropping conditions. They had not been used successfully, however, to estimate potential N availability under perennial grassland.

In this research, soil samples from two long-term perennial grassland sites were taken before and after N fertilizer application at rates of 0, 175, 350 and 525 kg/ha. The soils were incubated in the laboratory at 35 °C and were eluted at 2, 4, 8, 12, 16, 22 and 30-week intervals, the length of time prescribed for determining N mineralization potential. Because a plateau had not been reached, incubation was allowed to continue for 198 weeks and 148 weeks for the pre- and post-N samples, respectively. Total N was high, as was soil organic matter in both sets of soil samples. Nitrogen mineralization potential was underestimated after 30 weeks of incubation, and overestimated after 148 weeks. The closest agreement between N measured and the estimated N mineralization potential, came after 198 weeks of incubation. This study confirmed the high N-supplying capacity of soil under long-term perennial grasslands. It also indicated that the recommended 30-week period needed to estimate N mineralization potential under other cropping systems was insufficient for a perennial grassland soil. Cumulative differences in N mineralization were found with varying rates of N fertilizer application, but these differences were rarely seen on an individual weekly basis, nor were they significant at the termination of the experiment. The response to N application differed by site.

Several species of Heteroptera are responsible for kernel damage in wheat, Triticum aestivum L. (Poaceae), which affects bread-making quality. In Europe, the most noxious bugs belong to the genera Eurygaster (Scutelleridae) and Aelia (Pentatomidae). In the present work, five bug species frequently found in wheat fields in north-western Italy, Eurygaster maura, E. austriaca, Aelia acuminata, Nezara viridula and Carpocoris purpureipennis, were tested in field trials for their capacity to induce wheat damage. The sodium dodecyl sulphate sedimentation volume test was used as the qualitative control. Among the bug species tested, E. maura was the most noxious pest, with C. purpureipennis being almost as noxious as E. maura. In contrast, E. austriaca and A. acuminata, which have been considered the wheat pests of major importance, as well as N. viridula, caused no or only moderate damage to wheat quality. The adoption of an antiserum specifically produced with E. maura salivary glands proved to be effective and specific in detecting bug damage. Therefore, this polyclonal antibody is promising for the development of a reliable test for the quick evaluation of commercial wheat flour batches.

Most of our information on the subject of vitamins has been derived from experiments on small animals fed on synthetic diets. The direct application of the results of such experiments to the feeding of farm animals under practical conditions is not warranted. Animals differ in the degree of their susceptibility to disease caused by lack of vitamins, and laboratory diets, composed of foodstuffs subject to abnormal physical or chemical processes, such as heating under pressure, or prolonged extraction with fat solvents, have no parallel in animal husbandry.

The relationship between the voluntary dry-matter intake of grasses and their in vitro digestibility (DOMD), chemical composition and susceptibility to enzymic hydrolysis was examined in two experiments. The grasses were artificially dried and represented a range of species and varieties cut at various growth stages.

In both experiments some 70% of the observed variation in intake could be attributed to differences in in vitro digestibility between the grasses and between the growth stages when harvested. Estimations of acid detergent fibre, pepsin solubility and cellulose generally accounted for less than 70% of the variation in intake.

The enzyme digestion techniques, on the other hand, accounted for up to 79% of the variation. The content of enzymically unhydrolysable cell wall gave the highest correlation with voluntary intake (r = −0·88 and −0·89, residual standard deviation 5·5 and 6·2, for the two experiments).

It is concluded that simplified techniques based on cellulase digestion of plant material may be advantageously applied to breeding programmes with the expectation of identifying material high in digestibility and with good intake characteristics.

1. The availability of iron in five species of legumes has been investigated, using the rat as the experimental animal.

2. Two procedures were employed, namely, the increase in blood haemoglobin concentration, and the gain in total grams of haemoglobin, by nutritionally anaemic rats.

3. Inorganic iron, as ferric chloride, was shown to be significantly more available than the iron contained in the five legumes.

4. A significant difference in iron availability between alsike and wild white clover was obtained with both methods of expressing the results. Differences between other species were not significant.

5. The data are compared with those obtained for three species of grass in an identical experiment reported previously.

Yields and quality of herbage from a cocksfoot/white clover sward were compared over a 3-year period when cut repeatedly with a reeiprocating-blade mower to either 1 in or 2½ in from ground level or with a cylinder lawnmower to 1 in from ground level. The comparisons were made under two frequencies of cutting, namely five times per season at the ‘grazing’ stage, or three times at the ‘silage’ stage.

Cutting to 1 in from ground level with the reciprocating-blade mower gave a greater total yield of dry matter and crude protein than did cutting to 2½ in with the same mower in the first year, when the average dry-matter yield difference was 10·7 %, but no significant differences were recorded in subsequent years. It is suggested that the difference noted in the first year was due mainly to the harvesting at the first cut in the season of the layer of herbage between 1 and 2½ in from ground level, and not to any differential effects of the treatments on stem and leaf development of the cocksfoot.

Cutting to 1 in from ground level with the lawnmower gave smaller dry-matter yields than did cutting to 1 in with the reciprocating-blade mower at both stages of growth in the first year, but a slightly greater yield at the ‘grazing’ stage in the third year. The type of mower used affected the botanical composition of the sward.

1. Studies were made of the effects of varying ground water-levels upon the productivity and composition of Italian Ryegrass grown on a calcareous light peat in the Fenland area. Six cuts were taken throughout the season at 3 to 4-weekly intervals.

2. High ground water-level (approximately 15in. below ground surface) had a very deleterious effect on the total yield of fresh grass and of dry matter. Yields were little more than half of those obtained at medium and low water-levels (24 and 38 in. below ground surface, respectively).

3. High water-level apparently interfered with nitrogen metabolism in the soil, and considerably lower percentages of crude protein were found in the grass growing on the high water-level plots than at the other levels. On the other hand, the percentage of crude fibre remained fairly constant for all levels of ground water.

4. High water-level also had a depressing effect on the percentage of potassium, magnesium and chlorine in the grass. It had no obvious effect upon the calcium and phosphorus levels in the plants. The silica content of the grass rose steadily as the season advanced, this being most marked on the high water-level plots.

5. Physical examination of typical plants showed the effect of the various ground water-levels upon the development of the root systems, with consequent effect upon the chemical composition of the grass.

6. The composition of hay and aftermath showed similar changes to those reported for the green herbage.

7. The findings are discussed in relation to grassdrying policies in Fenland areas.

In Sub-Saharan Africa, cowpea is well known for its ability to survive under conditions of water stress and it plays an important role in regions where drought is the factor most limiting to crop yield. In the present study, the drought tolerance levels of 20 African cowpea accessions from three countries were evaluated. A number of the genotypes showed drought tolerance, the merits of stomatal behaviour and cell membrane stability to assess drought tolerance was demonstrated. Damage to the cell membranes caused by drought was less in tolerant accessions. Stomatal opening was also better regulated; the opening was smaller under drought conditions, thus reducing transpiration (T). The wide range of drought tolerance observed among the accessions suggests the possibility of breeding drought-tolerant cultivars in cowpea. Drought-tolerant accessions included Bafoussam 1, M.66, Bafoussam 3, Hluhluwa, Bafoussam 4, Balen, Makueni, Bafoussam 2 and Okhalweni and these could be recommended to breeders as valuable material for drought tolerance improvement in cowpea.