The relative importance of variation in the components of wool production to variation in wool production itself was estimated by two methods of analysis. About 30% of the attributable variation in total fleece weight was found to be due to variation in surface area and 70% was due to wool production per unit skin area. Between 50 and 60% of the variation amongst sheep in the latter character was found to be due to variation in fibre weight, the rest being attributed to variation in number of fibres per unit area (fibre density). The variation in mean fibre weight was further partitioned into 50 to 70% due to variation in mean cross-sectional area and the remainder to variation in mean fibre length.

Variation in wool production per unit skin area was also analysed according to growth period and position on the body. The results are discussed in relation to the partition of variance in wool production of other breeds.

There exists a large body of soil-water theory for ‘modelling’ soil-water movement and distribution. Yet simpler and sometimes cruder methods are often preferred. In part this preference is due to the fact that theory is not yet able to solve completely the more complicated situations that occur naturally, such as the intermittent application or removal of water in the presence of very hysteric soil-water properties. But in many instances it is due to the apparent difficulty of the analysis for the non-mathematically minded. For example, descriptions have been given of soil-water models, based on direct physical arguments, that are in fact finite difference analyses of the governing partial differential equations, but which make no reference to such equations or their existence. Indeed, the impression is sometimes given that soil-water physicists produce unnecessary, irrelevant and complicated analyses for something that is really quite simple. Unfortunately, the simpler approaches bypass possible complications that are revealed by the mathematically based analyses. It is therefore the purpose of this paper to take advantage of the close relation between the two approaches, and to draw attention to the steps that may be taken to avoid or reduce possible difficulties when following the simpler methods. In particular, it is hoped that the paper will lead to a more efficient use of computing facilities.

Stylosanthes humilis was grown at Brisbane at densities of 10, 50, 250, 850 and 3800 plants/m2 in boxes of sand which received basal nutrients, applications of 0, 10 and 50 kg P/ha as calcium dihydrogen phosphate, and frequent irrigation.

Maximum seed yield was 69 g/m2 at a density of 850 plants/m2. Seed yield was linearly related to the logarithm of density up to 250 plants/m2, and was comparatively stable over the upper density range, declining slightly at supra-optimal density. Inflorescence density exerted the primary control over seed yield, but seed set per floret and floret number per inflorescence were also influential.

The application of 50 kg P/ha increased yield of plant tops by 54% and seed yield by 20%.

The preweaning growth of the progeny of mature cows grazing high, medium or low quality pasture was evaluated. The cows were 5–9 years of age at the beginning of the study and were either purebred Hereford (H x H), first-cross Brahman x Hereford (B x H), Simmental x Hereford (S x H) or Friesian x Hereford (F x H). Hereford and Brahman bulls were mated to these cows for three mating seasons commencing in 1982, at Grafton, New South Wales, Australia. Records on 634 calves born over three consecutive years were used.

Most traits were subject to significant sire breed or dam breed effects or their interactions with one or more of the other main effects (pasture, year of birth of calf, cow age and sex of calf). The incidences of calving difficulty and stillbirths were exceptions. Stillbirths (mean of 3·8%) were not affected by any of the effects studied, while calving difficulty was affected only by sex of calf effect (males, 3·9%; females, 0·8%). The mean calving date of Brahman-sired calves was 11·4 days later (P < 0·05) than that of Hereford-sired calves. Differences between Brahman-sired and Hereford-sired calves for weaning weight were not significant for S x H (Brahman, 237 kg; Hereford, 232 kg) and FxH (Brahman, 238kg; Hereford, 238kg) dams. For HxH dams however, calves sired by Brahman were heavier at weaning (205 kg) than those sired by Hereford (193 kg) bulls, while for B x H dams the reverse was true (Brahman, 222 kg; Hereford, 231 kg). For calves with B x H dams average daily gain (ADG) was the same (957 g/day) for each sire breed, while for the other dam breeds, Brahman-sired calves had a higher ADG than Hereford-sired calves (862 v. 779, 1014 v. 946 and 1022 v. 950 g/day for H x H, S x H and FxH, respectively). Calves sired by Brahman bulls had > 90% eyelid pigmentation while Hereford-sired calves had 44–74%. On high quality pasture, the weaning weights and ADG of calves of F x H and S x H dams were higher than those of B x H and HxH dams. On medium quality pasture, weaning weight of calves of crossbred dams (B x H, S x H and FxH) were similar but higher than those of H x H dams. On low quality pasture, mean weaning weight of calves of B x H was higher than those of S x H and F x H dams, which in turn, were higher than that of H x H dams.

Seeds of the plant Crotalaria retusa L., containing 4·4% of the pyrrolizidine alkaloid monocrotaline, were fed in a finely ground form to groups of four pigs from 6 weeks of age. Six levels, 0·004, 0·01, 0·02, 0·05, 0·10 and 0·50% by weight of seed in the diet, were fed continuously for up to 19 weeks. In addition a separate regime, designed to mirror an outbreak of poisoning at a local piggery, consisted of feeding 0·10% for 3 weeks followed by 0·05% for 1 week.

Exposure to more than 0·01%, whether fed continuously or not, resulted in reduced voluntary feed intake and live-weight gain, and high mortality. At 0·50% a reduction in feed conversion efficiency was also obvious. Levels of 0·004% and 0·01% had no significant effect on the production performance of the pigs.

The results of this trial suggest that no more than 0·01% ground C. retusa seed should be included in the diets of pigs. When 0·004%–0·01% is included care should be taken as the long-term effect of the subclinical disease produced is not known.

Two experiments were carried out in Scotland 1984 to study the efficiency of energy utilization by Suffolk × Blackface lambs. In the first experiment, a digestibility trial, the lambs were fed three diets: roughage (R) consisting of chopped dried grass; concentrate (C) containing 700 g whole barley, 225 g ground barley and 75 g fishmeal/kg dry matter (DM); and a mixed diet (M) containing 500 g of roughage and 500 g of concentrate/kg DM. The DM and organic matter digestibility coefficients of diet M were lower than the ‘expected’ values calculated by summation of the separately determined digestibility coefficients of the component feeds. Similarly, the metabolizable energy (ME) value was 4·0% lower than expected.

In the second experiment, 40 lambs of c. 20 kg live weight (LW) were offered 50 kg roughage DM (ME 9·74 MJ/kg DM) and 50 kg concentrate DM (ME 12·21 MJ/kg DM) either as a mixture (treatment M) or sequentially (treatment S). Lambs on treatment S took 33 days longer to consume their allocation of food than those on treatment M, but achieved a similar final empty body weight and empty body composition. This contrasts with results predicted by a feeding standards model for lambs of a similar LW offered diets of the same ME content. The longer feeding period, and hence greater overall maintenance requirement, of lambs on treatment S was partly offset by associated effects causing a reduction in the total ME available to lambs on treatment M, and partly to improved efficiency of energy utilization for gain and/or a lower daily maintenance requirement of lambs on treatment S. Allowing for associated effects and the adoption of a variable maintenance requirement in current feeding standards would result in a more accurate prediction of animal performance.

A study was carried out during three successive years from 1970 to 1972 on different wool types. Breed groups involved were Merino (M), coarse-wool Barki sheep and five of their crosses. Traits studied were greasy-fleece weight, clean-fleece weight, kemp score and means of staple length and fibre diameter in the whole fleece.

The heaviest greasy fleeces were produced by ¾ followed by ⅝ M. Total average greasy fleece weight of the crosses was 3·43 kg. There was a general trend of increase in greasy fleece weight with increasing Merino proportion.

The total average percentage clean yield of the crosses was 42·2, and ½ M and ¾ M produced the heaviest clean fleeces. The total average clean fleece weight of the crosses was 1·44 kg. Skirting the fleeces caused a reduction in the within-fleece variability of staple length and diameter. Percentages reduction for staple length were 10·3, 9·6 and 14·6 and those for fibre diameter were 2·4, 5·0 and 9·5 in Barki, crosses and Merino respectively.

Barki had the coarsest diameter and the whole fleece of ¾ M showed the finest mean diameter of the crosses. The within-staple variability in distribution of fibre diameter was high in Barki and throughout the crosses. The average percentage medullated fibres was highest in Barki and decreased throughout the series of crosses. The ¼ M had the highest frequency medullated fibres of the crosses.

The longest mean staple in the crosses was produced by ¼ M. The within-fleece variability in staple length was generally low. In the crosses, the variability assumed slightly higher values than those of the parental breeds.

Kemp production was mainly contributed from the dorsal line, particularly from the back and hip.

As regards some wool and mutton characteristics, ⅝ M might be considered the most suitable cross-bred type.

With increasing Merino contribution in the crosses, the mean fibre diameter showed a decreasing trend, but a high within-staple variability was maintained throughout the crosses. Inter se mating, in most of the crosses, produced animals that showed relatively more uniformity between fleeces than either both or one of the crosses. Inter se mating of the different cross-bred types with selection of the desired uniformity in length and diameter would be recommended.

Attention has been drawn to the remarkable growth rates obtained in certain litters of pigs under farm conditions.

It has been pointed out that no explanation has been put forward to account for their occurrence.

The literature relating to the new dietary factor, physin (Mapson), essential for optimum growth and reproduction in experimental rats, trout and dogs, has been reviewed.

Experiments are reported in which rations, adequate as far as our present knowledge of essential dietary constituents goes, were fed to young growing swine. In each of three experiments, animals which received in addition 4 oz. of raw minced liver per day showed a 40 per cent. increase in growth rate compared with the controls.

When food intake was controlled according to the new method of individual feeding, the liver animals showed the same gains in weight as the animals receiving the basal diet alone.

Ten Scottish soils were cropped in a glasshouse with three sowings of perennial ryegrass (Lolium perenne, cv. Dutch Barenza) without added magnesium. After 25 cuts (185 weeks) growth was poor in some soils, but soil Mg was not limiting growth in others.

Uptake of Mg and the Mg concentration in the ryegrass correlated well over the entire cropping period with the equilibrium Mg-concentration ratio Mg/(Ca, Mg) = CR0, determined from the Mg quantity/intensity isotherms measured before cropping in 0·01 m chloride solutions. A CR0 value of 0·16 was required in the early stages of cropping to give 0·2 % Mg in grass dry matter.

Seven soils released 12–37 mg non-exchangeable Mg/kg, between one-fifth and one-third of the total Mg uptake. These reserves probably came from vermiculite minerals, but the release was too slow to maintain Mg concentrations of 0·2 % in the ryegrass.

Four experiments are reported in which the effects of a range of physiological ages of seed tubers on growth and yield in seed crops and regrowth of the progeny seed were studied. Increasing the age of seed in Home Guard, Arran Comet, Pentland Javelin and Désirée advanced emergence, tuber initiation and early growth but restricted leaf area index and reduced the number of tubers and seed tuber yield. In these varieties increasing the physiological age of seed shortened the dormancy of the progeny seed and slightly increased sprout lengths at replanting but in Home Guard had no effects on field growth and tuber yield.

In a further series of experiments at Tenby seed of five varieties (Home Guard, Red Craigs Royal, Désirée, Maris Piper and Stormont Enterprise) was multiplied over 2 years using husbandry methods designed to produce seed of contrasting ages. Once-grown seed from Tenby which had been planted and harvested early in the season was stored at either 4 or 12 °C and grown again at Tenby before being stored again at either 4 or 12 °C. The seed resulting from this multiplication over 2 years was compared with seed imported from seed-growing areas stored at the two temperatures. The seasons for the two multiplications at Tenby (1975 and 1976) were hot and were followed by an especially cold and late spring yet few differences between seed from Tenby and other areas could be detected. Where seed from different areas entered sprouting temperatures at different times and therefore produced different ages of seed at replanting large effects on yield were found. Storage temperature had large effects on regrowth of tubers in Home Guard, Red Craigs Royal and Stormont Enterprise for storage at 12 °C produced ‘little potato disorder’ in the majority of plants in one storage phase while storage at lower temperature produced full plant stands and yields. The results provided no support for the suggestion that repeated multiplication in warm lowland areas may lead to cumulative deterioration in the performance of seed.

A quantitative evaluation of the pigment in Murrah buffaloes of both sexes ranging in age from 1½ to 7 years revealed that dorsal areas had most pigment, while the lateral body areas and the extremities were intermediate and the ventral and axillary regions revealed the least pigment. Maximum concentration of melanin granules occurred in stratum cylindricum, which gradually declined towards stratum corneum which was fully non-pigmented in axilla, groin, inter-digital and inter-dewclaw areas.

Pigment granules blackened in silver preparations and were seen concentrated as protective ‘nuclear caps’ in the supranuclear zone of the cells of stratum germinativum. The infranuclear light-staining cytoplasm contained PAS reactive glycogen granules.

The efficiency of the utilization of the energy of casein in adult fowls at different feeding levels both for maintenance and for lipogenesis, was studied. The casein was utilized for maintenance with an efficiency of 66·6 ± 1·3% of the gross energy and of 83·7 ± 1·4% of the metabolizable energy. For lipogenesis efficiencies were 51·6 ± 2·15%, and 61·3 ± 2·6% respectively.

Under intermediate deepwater (15–50 cm) conditions, sulphur-coated urea (SOU) drilled behind the plough at sowing was superior to other coated (neem, lac, coaltar) urea materials and broadcast incorporation of prilled urea in increasing the yield of direct-sown rice. In transplanted rice, the grain yield was highest with urea super granules (USG) placed 30 days after transplanting (DAT) followed by SOU broadcast incorporation at planting. N-use efficiency increased considerably with SCU drilled behind the plough or USG placed 20 days after sowing in shallow standing water in direct-sown rice and SCU broadcast incorporation or USG placed 30 DAT in transplanted rice.

In Part III of this series of communications we recorded that no mammary pigment could be found in the old sows that were examined by us, and we suggested the possibility that such pigment had previously been present and had been destroyed or removed during the periods of glandular activity.

1. For both genetical and methodological reasons, tests for quality, in the majority of breeding schemes, are not required at the early stages of the breeding process.

2. Reliability and definition of any one empirical test is not sufficient to safeguard against losses of valuable material.

3. It is suggested, therefore, that as a rule agronomically promising lines should be carried on to a stage where comprehensive tests, using a number of selected methods, can be carried out, preferably over a number of seasons. It may be questioned whether a combination of such tests as the wholemeal fermentation and the gluten swelling tests (Pelshenke, 1938a) would suffice. In the light of the available evidence a testing system might be suggested comprising baking tests together with such “indirect” and, better still, “analytical” methods as will afford accurate information of an analytical nature.

4. This review of the testing problem suggests the conclusion that empirical tests are limited in their significance and reliability, and that only an increased knowledge of the fundamentals can afford a truly scientific approach. It should be admitted that the plant breeder, with his insistence on empirical tests where fundamental knowledge was lacking, has side-tracked the cereal chemist from the narrow path of scientific approach all too often. It is questionable whether this has been to the ultimate advantage of wheat breeding.

5. Inheritance studies on quality should greatly facilitate the task of the breeder. They will become feasible and valuable only when the nature of the desirable characters and the true significance of the testing methods are clearly understood.

Tetraploid lines were produced from colchicine treatments of European multigerm diploid material, and seeded in polycross plots. The same lines were crossed with European multigerm diploids to give anisoploid varieties, and also used as pollinators of American male-sterile diploids to yield monogerm and multigerm triploid varieties. Bigerm triploids were obtained from male-sterile hybrids heterozygous for the monogerm character, using European multigerm O-types in the grandparental generation. Double-cross monogerm triploids were obtained by crossing male-sterile diploids with non-equivalent O-types to provide male-sterile hybrids, and pollinating these with outbred tetraploids.

Results from 35 root-yield trials showed that the sugar yields of the anisoploids and triploids were similar to those of contemporary commercial varieties, but that outbred tetraploids were slightly, and inbred tetraploids considerably, less productive. Changes induced in characters other than root weight by chromosome-doubling of diploid material were sometimes important, but not consistent in magnitude or direction. It is suggested that these changes result from selection and random drift rather than the ploidy change.

A seed-yield trial demonstrated advantages of using hybrid seed-parents for triploid seed production. Problems of seed quality are discussed with particular reference to triploid varieties.

It is concluded that the main importance of multigerm anisoploid varieties was in their combination of good sugar yield with near-monogerm fruit clusters at a time when commercial monogerm varieties were deficient in yield; the chief value of triploidy lay in its application to the short-term improvement of genetic monogerm varieties. The development of monogerm anisoploids is considered unlikely; but some advantages of deriving monogerm triploid varieties from tetraploid seed-parents are indicated, and it is suggested that these may become increasingly important in the future.

1. Activity of Lumbricus terrestris, Allolobophora caliginosa and A. chlorotica was unaffected by 15 mg. hexoestrol in solution in 500 g. soil.

2. Activity and reproduction of A. caliginosa was unaffected by 10 mg. hexoestrol in 500 g. soil, but 100 mg. and over affected activity and stopped reproduction.

3. Egg capsules of A. caliginosa and A. chlorotica developed normally in a saturated aqueous solution of hexoestrol.

4. No effect on the soil fauna of grass plots due to grazing with implanted bullocks was observed.

The size of the sink on two indeterminate (cv. Hampton and cv. TGM 119) and two determinate (cv. Bossier and cv. TGM 294) cultivars of soya beans were reduced by continuously limiting the number of pods developing at each fruiting node to either one or two, starting from 2 weeks after anthesis, in three field experiments (early 1980, late 1980 and early 1981). Thiswas in order to evaluate the effects of sink size on the development of pod and seed characteristics as well as to quantify the inter-relationships between these characters under humid tropical conditions.

Persistently reducing the number of pods developing at each fruiting node consistently significantly reduced the number of pods per plant, the pod and seed dry weights per plant, the total number of seeds per plant and the harvest index (seed weight as a proportion of total dry weight) in all cultivars when compared with the control. On the other hand, the treated plants of all cultivars generally had longer pods, heavier individual pods and seeds, more seeds per podand greater leaf area and leaf dry weight as well as greater specific leaf weight than the control plants. Compensation indices (percentage increases in size over control) were 25–30% for weight per pod and seed weight per pod; 11–16% for weight per seed and number of seeds per pod and 2–5% for pod length in the treated plants.

Most of the characters measured (except individual weight of pods and seeds, seed weight per pod and number of seeds per pod) had significant interaction effects of sink size, cultivar and season; season had the highest correlation ratio, followed by cultivar, and sink size had the least. Also, nearly all components of seed yield were positively highly significantly correlated with one another; the number of seeds per pod and the number of pods per plant accounted for 76% of the variation in seed dry weight per plant.

It would seem therefore that under the prevailing humid tropical conditions, the most important component of seed yield in soya bean is the number of seeds per pod, as affected by the sink size.

After it had become evident that vitamin B12 can be considered as a part of the so-called ‘Animal Protein Factor’, several experiments with young fattening pigs have been carried out in the Netherlands. The purpose of these experiments was to gain experience as to the value of products rich in vitamin B12 for pig feeding. In these trials 312 animals were used.

The results can be summarized as follows:

1. Substitution to a large extent of animal protein by vegetable protein in rations containing tho same total percentage of protein resulted in a retardation of growth.

2. Addition of vitamin B12 supplements to feed mixtures low in animal protein in this series of experiments generally gave better results than could be obtained without this addition. In the majority of cases, however, the results did not equal those of the groups which received rations containing the usual amount of animal protein.

3. Vitamin B12 can be considered as a component of the animal protein factor, but besides this there probably exist other factors which contribute to the special value of animal protein for young pigs.

4. In circumstances such as prevail in the Netherlands, little benefit can be derived for pig fattening from the use of products rich in vitamin B12.

Pyrethrum is a small bushy perennial crop cultivated for its flowers which have insecticidal properties. Pyrethrins, the active principles in the flowers, are contact insecticides causing nervous breakdown leading to paralysis and death of insects. Kroll (1963) and Parlevliet, Muturi & Brewer (1968) have shown that the flower yields of pyrethrum could be improved by applying P fertilizer whereas N and K fertilizers did not increase the yields. On the other hand, Mwakha (1979a, b) showed that pyrethrum responds to N fertilizer on soils deficient in N. The present investigation was carried out to study the response of pyrethrum to various rates of application of N, P and K and sources of phosphorus.