This study is the first comprehensive estimation of breed parameters for the Jamaica Hope breed of dairy cattle. It has shown that the breed has considerable potential for milk production undser good husbendry in a tropical environment. Improvements in reproductive performance may be achieved, without prejudice to production performance, by using milk yield per day of calving interval (which has a moderatoly high repestability) as a criterion for selection.

Two non-dwarf and two dwarf, autumn-sown determinate genotypes of white lupin (Lupinus albus L.) were sown at three sites in north-west Europe in the crop years, 1995–96, 1996–97 and 1997–98. Fully factorial experimental designs were used to analyse all combinations of genotype, seed rate and row spacing. Canopy expansion, expressed as the percentage of Photosynthetically Active Radiation (PAR) intercepted, and above ground dry matter (DM) accumulation were measured at frequent intervals during the main growing season at Rothamsted in the UK and Lusignan in France. The data from Rothamsted were used to derive models for the two processes, which were compared to the data from Lusignan, France.

Crops with more than 23 plants/m2, 25 main stem leaves per plant or 1400 leaves/m2 were able to intercept more than 80% of the incident PAR. There were small differences in canopy expansion between genotypes. The non-dwarf genotypes began expansion slightly earlier (100–150 °Cd or thermal time in °Cdays, base temperature = 3 °C) than the dwarf genotypes. Crops sown on rows wider than 40 cm apart or with low plant densities (less than 23 plants/m2) were also slower to expand the canopy and intercept the PAR.

The maximum quantity of dry matter accumulated by a genotype in the season (476–1044 g/m2) was related by a conversion efficiency (e) to the cumulative quantity of PAR intercepted. Values of e were generally in the range 0·92–1·65 g DM/MJ PAR during the early part of the growing season, which was comparable with other work on temperate-zone grain legumes. The non-dwarf genotype Ludet achieved an unusually large value of e (3·13 g DM/MJ PAR) and accumulated 1355 g DM/m2 at Lusignan in 1998. Late season drought in 1995–96 at Rothamsted produced some low values of e (0·75 and 0·88 g DM/MJ PAR).

The seed yield was not related to the quantity of dry matter accumulated as harvest index varied from 22·3% to 49·7%. Maximum seed yield (4·54 t/ha) was produced from a low plant density (15·9 plants/m2). Mutual shading, caused by any combination of high plant densities, large numbers of leaves per plant or sowing on wide rows (>40 cm; at high plant densities within the rows) appeared to limit seed yield potential.

Zinc deficiency has been one of the major micronutrient disorders of flooded rice. Several researchers have reported that Zn deficiency could be corrected by the application of various Zn fertilizers to soil (Mikkelsen & Brandon, 1975), to seedling root (Yoshida et al. 1970; Katyal & Ponnamperuma, 1975) or to plants as foliar spray. Also there has been much speculation about the most suitable form of Zn fertilizer for correcting Zn deficiency of flooded rice. A glasshouse study was conducted to compare the effectiveness of various Zn fertilizers for rice grown under flooded conditions.

In the Agriculture Returns published by the Board of Agriculture, the figures for swedes and turnips are given together. Taking the figures for 1913, we find that swedes and turnips were grown on 1,757,000 acres of land in the United Kingdom, and that the total weight of crop obtained was 25,319,000 tons. No other green crop occupied so large an area, and no other crop of any kind produced as great a weight of fodder.

The availability to grass of the nitrogen in liquid anaerobically digested sludge (LDS) and liquid aerobic sludge (LAS) was investigated in a 2-year field trial. The mean availability of the nitrogen in the LDS over the 2 years was 44% on a freely drained sandy soil and 34% on a poorly drained clay soil. The corresponding values for the LAS were 56 and 44%. A greater inhibition or organic-matter decomposition by clay particles or a greater loss of nitrogen by either ammonia volatilization or denitrification were all possible reasons for the lower availability of the sludges on the clay soil. Investigation of the magnitude of gaseous losses of nitrogen from sludge-amended grassland under U.K. conditions is required. Current models of the availability of the nitrogen in liquid sludges may not be realistic if these losses are significant.

The preparation of natural humic acids from soil, peat (Dopplerite) and “Adco,” and of artificial “humic” acids from sucrose, cellulose, dextrose and glycine (Maillard), furfural, hydroquinone and lignin, and their purification is described.

Their elementary composition and their behaviour under conductometric titration with ammonia have been studied. The artificial products from sucrose and furfural did not behave as acids, but all the natural products, and the artificial products from cellulose, hydroquinone and lignin possessed the properties of colloidal acids.

Preliminary investigations into the “humification” of furfural and ω-hydroxymethyl furfural, and into the interaction of dextrose with amino bodies, are described.

It is well known that different flours vary enormously in respect of the size and shape of loaf they yield on baking. The factor which determines the quality of flour in this connection has been termed “strength” and the latter has been denned as “the capacity of flour for making large well-piled loaves”(1).

Many views have been held from time to time regarding the explanation of flour strength from the chemical standpoint. The earliest view was that strength was determined by the gluten content of the flour, which by virtue of its tenacity was able to retain in the bread the carbon dioxide produced as a result of the activity of the yeast. Many cases, however, were investigated where flours possessing a high gluten content were not so strong as a flour with a low content of gluten. Furthermore, no accepted regularity has been found to exist between the strength of flours and the water-holding or gas retaining capacity of their glutens.

Ramularia beticola was prevalent in sugar-beet seed crops in Oxfordshire, Gloucestershire and Lincolnshire in July each year from 1966 to 1971, and defoliated some crops prematurely. It was scarce in Bedfordshire, Huntingdonshire and Essex, and this distribution could not be related to method of growing the crop or density of plant stand. A method is described for assessing leaf spot incidence in beet seed crops after bolting is complete. Fungicide sprays delayed disease development by ca. 2½ weeks.

March-born non-cyclic Suffolk × Galway ewe lambs were treated with progestagen pessaries while being either fed fresh-cut grass ad libitum, or restricted to 50% of appetite and at pessary removal half of the animals on each nutritional treatment received either 600 i.u. or 300 i.u. PMS. Averaged over both levels of PMS, 97·5% of the lambs showed oestrus when fed ad libitum but only 67·5% of those on restricted feeding responded. When feed intake was not restricted there were no differences due to PMS level but when feed intake was restricted the higher dose level of PMS resulted in a greater percentage showing oestrus and a significantly higher ovulation rate. The dose level of PMS had no effect on the time of oestrous onset but restricted feeding resulted in delayed onset and poor synchronization of oestrus. Duration of oestrus was greatest for lambs fed ad libitum given 600 i.u. PMS and least for those on restricted feeding given 300 i.u. PMS but the difference was not significant. A minority of lambs showed broken oestrous periods.

Three methods for the determination of cellulose have been compared for their value in nutritional studies, and have indicated the applicability of the procedure of Druce &Willcox (1949) in this connexion.

The use of the method of Crampton & Maynard (1938) has been shown to give an erroneous picture of the extent of cellulose digestibility, and it has been concluded that the procedure is not satisfactory.

Whey is the liquid which drains from the curd produced by the action of rennet on milk or from the curd formed by natural souring of milk or by the addition to milk of weak acids or other precipitants.

The concentration of cheese-making at factories in recent years has resulted in the production of large quantities of whey at centres where adequate provision has not been made for its disposal. Part of it is consumed as pig food. The remainder is discharged into streams and sewers. This involves the destruction of large amounts of valuable food material. To prevent contamination, discharge into streams is now generally prohibited. Sometimes it is irrigated on to the land as manure. On the farm practically all the whey produced is consumed as pig food.

Variation in urinary creatinine in nine male and twelve female buffalo calves divided into three equal groups on diets containing three levels of dietary protein intake (low, medium and high) was estimated. The variation in urinary creatinine (% and total) was large from animal to animal and also from day to day (P < 0·01) in the same animal. It was not affected (P > 0·05) by the level of dietary protein. The creatinine-nitrogen ratio decreased (P < 0·01) with increase in the protein level of the ration, but the creatinine coefficient (creatinine per kg body weight) did not differ significantly (P > 0·05). The male and female animals responded similarly.

It was concluded that urinary creatinine (% and total) and the creatinine coefficient cannot be used as an index either in nutrient balance studies or for evaluating ruminant nutrition in general. The creatinine-nitrogen ratio could also not provide a suitable yardstick to evaluate protein status of the animals because of the significant interaction of days × protein. The nitrogen balance is considered to be better for this purpose.

Six sites of variable soil type and environments in England and Scotland were sown with winter wheat (Triticum aestivum L. cv. Mercia) in the autumns of 1992 and 1993 with optimum inputs for growth. Crop monitoring between February and grain maturity provided data to investigate environmental and physiological factors important in controlling biomass accumulation.

With increasing use of crop modelling as a tool for interpreting experiments and as crop management decision support systems, it is important that all influences on crop productivity are understood. The ‘radiation use efficiency’ or radiation conversion coefficient provides a convenient basis to study these influences.

Significant differences in seasonal radiation conversion coefficients were observed between sites (P < 0·001), ranging from 2·82 to 3·87 g total dry matter/MJ absorbed photosynthetically active radiation. A series of simple dry matter models were developed to help explain biomass accumulation in relation to a number of environmental variables (using the measured green area index as an input) with correlation coefficients [ges ] 0·98 obtained across all sites. Apart from sunlight, differences in the canopy's ability to accumulate nitrogen and maintenance respiration costs were the most significant factors (P < 0·001). The nitrogen effect suggests changes in the conversion of assimilates with nitrogen availability, despite relatively high nutrition levels ([ges ] 180 kg N/ha).

Over all sites the canopy extinction coefficient could be described as a linear function of the site spring time plant population (P < 0·01). A more detailed model considered canopy light attenuation to vary between sites according to sowing date and autumn/winter plant establishment and environment.

The soluble tuber proteins of potato (Solatium tuberosum) may be separated by electrophoresis on the basis of charge or molecular weight (Stegemann & Schnick, 1982; Maier & Wagner, 1981: Park et al. 1983). Considerable cultivar specific variation exists in the band patterns of these proteins and separation of native proteins in 6% polyacrylamide gels at pH 7·9 has been used as the basis of characterizing cultivars for the Index of European Potato Varieties (Stegemann & Schnick, 1982).

The competitive abilities of two natural populations of Dactylis glomeratafrom Norway and Portugal were studied under three controlled environments, 7 °C with an 8 h photoperiod, 20 °C with a 16 h photoperiod, and 30 °C with a 16 h photoperiod. The temperature and daylength treatments affected both the growth habits and the relative competitive abilities of the populations. At 7 °C, 8 h photoperiod the Norwegian population became prostrate and was suppressed in mixed culture compared with its performance in monoculture, and an increased specific leaf area indicated competition for light. At 30 °C, 16 h photoperiod the Norwegian population was more erect than the Portuguese, and more aggressive, with a better performance in mixed culture than in monoculture. The performance of the Portuguese population was not affected significantly either by culture or by environment. At 20 °C, 16 h photoperiod, however, the Portuguese population was suppressed, while the Norwegian population performed better in mixed than in monoculture. This yield increase of the Norwegian population was greater than the decrease of the Portuguese population, and so the mixed culture yielded significantly more than the mean of its component monocultures, whereas at 7 and 30 °C the mixed culture yielded no more than the mean of its monocultures. The physiological basis of these competitive effects is discussed.

1. Of the three sources of supply of nitrogen, rape cake gave the highest mean yields in the absence of superphosphate; while nitrate of soda gave results significantly better than those obtained from ammonium salts.

2. Superphosphate is of importance to the barley crop, giving greatly increased yield when applied.

3. Sulphate of potash seems to have an adverse influence upon the barley yield.

4. The deterioration of the barley plots is much heavier than on the wheat plots. The convention of ascribing the whole linear term to deterioration may not be as true for some plots as for others. Part of the diminution in mean yield may be due to slow changes other than deterioration.

5. The mean annual percentage diminution is least on those plots in receipt of superphosphate and emphasises the importance of phosphoric acid not only in increasing the mean yield, but in maintaining the fertility of the soil.

6. Barley is more variable than wheat and is more subject to the influence of meteorological conditions.

7. The slow changes other than deterioration are relatively unimportant and seem closely connected with the manurial treatment. The cause of the slow changes is obscure, but there were probably special influences operating on certain of the plots.

The present study was carried out during 1996, 1997 and 1998 to estimate the additive, dominance and epistatic components of genetic variation for yield, yield components and wilt infection by using 90 triple test cross families and their parents, F1 and F2 in each of four sesame crosses, i.e. Bengalian×Giza 32 (TTC1), Intro 259×Giza 25 (TTC2), Intro 413×Intro 777 (TTC3) and Shandaweel 5×Line 107 (TTC4). Mean squares from the genetic analysis of variance and the overall epistatic gene effects were highly significant differences for all studied characters. The [i] type (additive×additive) was the most important epistatic effect for height of the first capsule (TTC4), number of branches/plant (TTC1 and TTC3), length of the fruiting zone (TTC1, TTC2 and TTC3), days to the first flower and number of capsules/plant (TTC1, TTC2 and TTC4), 1000-seed (TTC3), wilt infection percentage (TTC3 and TTC4) and plant height, capsule length and seed yield/plant in all crosses. The ratio of (H/D)1/2 confirmed the presence of partial dominance for all studied traits. The highest proportion of recombinant lines was obtained for days to the first flower, number of branches/plant, height of the first capsule and seed yield/plant in TTC3 and plant height, capsule length, length of the fruiting zone number of capsules/plant, 1000-seed weight and oil percentage in TTC2.

Rice necrosis mosaic virus infection induced different reactions on monocotyledonous and dicotyledonous plants under field conditions. Under identical conditions virus infection reduced the grain yield of rice by inhibiting plant growth, whereas in dicotyledonous plants like Ludwigia and four fibre crops (including jute infection with sap from rice necrosis mosaic virus-infected rice plants, but not with sap from healthy plants) markedly increased yield, plant height, leaf size, stem diameter, seed weight and number of seeds per capsule.

Over 5 years (1987–91), the progeny of rams selected for fast (Low T-half) or slow (High T-half) glucose clearance after an intravenous glucose tolerance test, differed significantly in glucose tolerance. In comparison with an unselected control, the line differences were mainly in the direction of Low T-half. They appear to have arisen during the establishment period, with little evidence of enhanced divergence over the four subsequent years of continued selection (heritability 0·10±0·03). The Low line had higher plasma insulin concentrations during the glucose tolerance test than the High line. Basal plasma concentrations of glucose were lower, and urea higher in the Low than the High line. In addition, carcasses of Low line ram progeny had more subcutaneous fat at the same carcass weight than High line carcasses (11% higher GR in the final year of the experiment). Selection of sheep for glucose clearance appeared to be associated with differential partitioning of nutrients into adipose tissue, the pooled genetic correlation between T-half and GR being −0·28±0·13.

In this paper an examination is made of the processes operative and the limits of accuracy of the electrical method of determining soil moisture.

The resistance over a small plot is found to vary under similar conditions and it is concluded that these differences are most probably due to actual differences in moisture or other factors.

The effect of the distance apart of the electrodes is investigated and a probability of a minimum resistance between two electrodes being observed under certain conditions is indicated.