Wool production from different flocks of Ossimi, Rahmani and Barki Egyptian local sheep, raised at six different locations in the country was studied. Different genetic parameters for greasy fleece weight of the three breeds were estimated.

Location was of significant effect on annual greasy fleece weight of Rahmani sheep only. With the adjustment for differences in yield percentages, differences in clean wool production from one location to another were slight for the three breeds. Age of ewe was of highly significant effect on annual greasy fleece weight.

Heritability estimates of annual greasy fleece weight of the ewes were found to be generally low in the three breeds (range 0·00–0·34). The estimates differed markedly with age; those of the yearling fleece weight of Rahmani and Barki ewes were the highest, being 0–19 and 0–34, respectively.

Repeatability estimates of annual greasy fleece weight were also low, being 0·11–0·04 and 0·29 for Ossimi, Rahmani and Barki ewes, respectively.

Estimates of genetic correlation between yearling greasy fleece weight of the Ossimi and Rahmani ewes and their weaning and yearling body weights were high and positive. Those between annual greasy fleece weight of the ewes and their reproductive performance traits differed greatly in the two breeds.

Seven non-destructive field measurements were made on 1270 pigeon-pea plants varying widely in age, size and plant type, before determining their dry weight. The non-destructive measurements were generally highly correlated with one another, and were all significantly correlated with total, total above-ground and structural dry weights. In one experiment dry weights were best predicted by a multiple regression using stem diameter, length of longest branch and number of branches as predictors. Field height and stem diameter were the best predictors in a second trial. It is suggested that dry weights can be estimated by taking certain measurements at regular intervals, simultaneously sampling a number of plants to determine the best predictive equation. Where it is unnecessary or impracticable to do this, stem diameter appears to be the best single index of dry weight.

Yields of sugar and responses to fertilizers were determined in about 400 fertilizer experiments on farms throughout the sugar-beet growing areas of Britain during 14 years from 1957 to 1970. The soil at each experimental site was described and classified and the records of the experiments have been examined to determine which properties of the soil influence sugar yield. The effect of year, rainfall, elevation, region and other factors such as sowing and harvesting date were also investigated.

Year-to-year variation accounted for 20 % of all variation in yield; increasing amounts of rainfall during the growing season appeared to decrease yield. There was a significant long-term trend of increasing sugar yield from the experiments of 0·042 t/ha/year. The experimental yields closely followed national yields each year but were always greater. Delay in sowing and early harvesting depressed yield by 0–02 and 0·01 t sugar/ ha/day respectively. Yields in Scotland (average 5·23 t/ha) were approximately 1·4 t/ha less than in England and Wales, but there were no evident regional differences within England and Wales.

Soil regarded as moderately drained yielded better than either well-drained or imperfectly drained soil, which in turn yielded better than droughty and poorly drained soil. The difference in the adjusted yield between drainage classes was 1·0 t/ha. Surprisingly, topsoil texture had no consistent effect on mean yield (as distinct from response to fertilizer). Subsoil texture, however, had an appreciable effect, the crop on sandy subsoil and chalk or limestone yielding poorly whilst that on silt or peat yielded best. The range of differences in sugar yield due to subsoil texture was almost 2 t/ha.

Yields were also examined in relation to soil profile type. Broad division into major soil groups gave meaningful differences but fine division by soil series was only useful for the 11 series on which at least ten experiments had been made. The crop yielded most sugar on gleyed calcareous soils, peats and humic gleys, and least on rendzinas and brown calcareous soils. Responses to nitrogen and potassium but not to phosphorus were affected by both topsoil and subsoil texture. Nitrogen and potassium both increased yield most on sandy soils and least on fine silts and peats.

The morphology, chemical and physical condition of soil clearly affect sugar yield greatly and further research is needed in experiments planned specifically to measure their influence and provide more precise guidance for selecting the best land for the crop.

Skin was examined from a total of 70 lambs obtained at the foetal age of 75, 90, 100, 120 and 135 days. The rate of follicle development was not greatly dissimilar from that previously described in improved breeds. The Shetland showed least difference from improved breeds, and the Mouflon x Soay was most retarded, but the pure Soay foetuses were closer to the Shetlands than to the Mouflon cross-breds.

Metabolism trials were conducted with sheep to study the effects of conservation of herbage as silage, frozen or artificially dried grass upon the magnesium and calcium availabilities in the conserved products.

When the diet was changed, approximately isomagnesaemically, from hay and barley to each of the conserved products, there was a highly significant (P < 0·001) decrease in the plasma magnesium concentration. However, the plasma magnesium concentrations of the ewes eating the artificially dried grass were significantly lower (P < 0·05) than the corresponding values when they ate the frozen grass or silage. No changes were seen in the plasma calcium concentrations.

The apparent availability of magnesium in the silage was significantly higher (P < 0·05) than that in the frozen and artificially dried grasses. Also, the apparent availability of magnesium and calcium was lower in the dried grass than in the other two products, whilst the retention of both magnesium and calcium was significantly lower (P < 0–05) when the dried grass was eaten as compared with the frozen grass and silage. The percentage urinary loss of magnesium was greatest on the silage and least on the dried-grass diet.

It was concluded that artificially drying grass caused a reduction in magnesium availability.

Grazing with sheep was compared with cutting, in each case at three frequencies, four, five and six defoliations per year, on a lucerne—cocksfoot ley. The treatments were applied in one year and their effects measured during that year and at cuts in June and August of the following year. One experiment began in 1963 in the second harvest year of a ley and a second began in 1964, on an adjacent site, in the third harvest year of the ley. Cutting four times in the year allowed lucerne to persist satisfactorily in both experiments. In the 1964 experiment cutting five or six times and grazing rather than cutting had no apparent, serious, adverse effect on the lucerne compared with cutting four times. In the 1963 experiment, however, increasing the number of cuts and grazing rather than cutting had a large adverse effect on the lucerne, and in the most extreme treatment, grazing six times, the proportion of lucerne was reduced to 2 % of total herbage yield the following June compared with 66% on the four-cut treatment. The contrasting results in the two experiments seem associated with weather differences, 1964 being a much drier, more sunny growing season than 1963, and perhaps with the differences in age of sward, individual lucerne plants perhaps having bigger roots with more reserves in 1964 than in 1963. During the treatment year increasing frequency of defoliation tended to increase the N content of both species and grazing compared with cutting generally increased the N content of cocksfoot. During the year following the treatment year the N content of the two species was little affected by the experimental treatments. The implications for farm practice are considered.

The production of toxic levels of ethanol in the stomachs of neonatal ruminants resulting from fermentation of glucose by resident yeasts occurs only in the absence of fat from the diet. Daily levels of ethanol and numbers of viable yeast were measured on samples of stomach contents for 21-day periods. Milk fat was shown to control the ethanol production in lambs and calves (but not in vitro in culture), the quantitative nature of this control was demonstrated by experiments with cream using lambs. Nine dietary fats in commercial use homogenized in fat-free milk, a commercial catering ‘milk’, and an intravenous lipid feed were all tested in lamb-feeding experiments, compared with whole and separated milk, and an inert oily hydrocarbon, liquid paraffin.

Twenty cultivars of P. vulgaris differing in growth habit, and inoculated with an efficient strain of R. phaseoli, were sampled weekly in the period 22—99 days after planting. Acetylene reduction and specific nodule activity were similar to or better than those reported for other grain legumes, and were higher than achieved by a soya-bean cultivar. Though the period of active fixation was limited, nitrogen gains estimated at 25—30 kg/ha/growing cycle were obtained. Climbing beans were superior to bush beans in acetylene reduction and specific nodule activity, but differed little in nodule development. Two varieties, Cargamanto and Sangretoro, were outstanding in fixation. Differences between varieties in nodule to root ratio, and in rate of N accumulation in the leaves were shown. Both groups of plants stored appreciable starch in the stem after flowering. The results are related to the need for N fertilization in Latin America.

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.