Recent developments in chemical weed control in sugar beet have been reviewed. Two main approaches to the problem of providing reliable season-long control of annual weeds in sugar beet are, (a) the use of mixtures of herbicides applied pre-planting and incorporated into the soil during seed bed preparation, and (b) the use of split applications with a residual herbicide applied pre-emergence followed by a contact herbicide applied post-emergence.

The second approach (b) was examined in a series of field experiments from 1967 to 1969, on light to medium sandy loam soils in the West Midlands. Comparisons were made between pre-emergence application of lenacil and pyrazon, pre-emergence application of lenacil and pyrazon followed by post-emergence application of phenmedipham, and post-emergence application of phenmedipham for weed control in sugar beet.

Under dry soil conditions in April 1967, lenacil and pyrazon controlled only about 40% of the annual weeds, but in 1968 and 1969, when moist soil conditions predominated in April and May, lenacil and pyrazon controlled 80–95% of the annual weeds.

Phenmedipham applied post-emergence gave about 90% control of annual broadleaved weeds initially, but it seemed unlikely that a single application of this herbicide would provide satisfactory weed control in sugar beet.

In each of the 3 years 1967–9, a split application of a soil-acting residual herbicide (pro-emergence) followed by phenmedipham (post-emergence) gave outstanding weed control and enabled sugar beet to be established and grown until mid-June at least, in a near weed-free environment. It was concluded that this technique was the most effective for weed control in sugar beet on light to medium sandy loam soils in the West Midlands.

Eight cultivars of peas (Pisum sativum L.) were evaluated for six traits in a diallel experiment using regression coefficients, correlations and combining ability estimates. Regression coefficient was high, indicating large additive effects for 100-grain weight. Yield was significantly and positively correlated with plant height, number of pods per plant and 100-grain weight, indicating that selection for either of these would result in higher yield. The best index of yield among the traits studied was number of pods per plant. Significant general combining ability (GCA) variances and specific combining ability (SCA) variances were observed. GCA variances were larger than SCA variances except for yield, suggesting predominance of additive gene effects.

1. The object of this investigation was to determine the extent to which the decomposing power of soils within a climatic region is influenced by:

(a) the geological character of the rocks from which the soils are derived,

(b) the nature of the vegetative covering.

2. A short account is given of the geography, climatology, geology and pedology of Glamorgan. The soils of South Glamorgan appear in general to be Brown Earth types.

3. In studying the rate of decay it is necessary to obtain an index of the intensity of the total biochemical processes taking place. One of the best and most suitable of indices for this purpose is CO2 evolution.

4. A type of apparatus used by a previous investigator (Neller) to measure the CO2 evolved from soil was tested and found to be unsatisfactory. Thus a suitable apparatus had to be evolved. This apparatus is described in detail.

1. Comparisons are made of the results obtained in the analysis of clays, especially of clay fractions separated from soils, by the standard sodium carbonate fusion method and by attack by means of mixed acids. Provided certain precautions are taken, in the latter case, the percentages of silica obtained are shown to be comparable with those given by the fusion method.

2. A possible disadvantage of the acid method is that the attack of the clay is not invariably successful, but treatment of the silica with hydrofluoric acid provides a convenient and reliable means of detecting those cases in which failure occurs. Such clays must be decomposed by fusion with sodium carbonate.

High yielding ruminant livestock require high nutritive value in forage for maintenance, growth and production. Climate change has been documented as impacting on the nutritive value of forage plants. Therefore, the aim of this study was to investigate the impact of increased temperature in combination with CO2-enhancement on the nutritive value of orchard grass (cocksfoot; Dactylis glomerata L.), as a C3 model plant, widespread in mountainous permanent grassland plant communities. Functional traits and forage quality of orchard grass were investigated both under ambient (C0T0) and under simulated, future climate conditions (C2T2) with increased temperature (+3°C) and enhanced CO2 concentration (+300 ppm) under field conditions. Plant samples were taken from each of the three growths over a period of three consecutive years and numerous functional properties and forage quality parameters were determined. Special attention was paid to the determination of water-soluble carbohydrates (WSC), crude protein (CP), non-protein N (NPN) and metabolizable energy (ME) as possible indicators for different climatic conditions. It is hypothesized that (i) functional traits and (ii) forage quality of orchard grass are altered by increased temperature and higher CO2 concentration. The results showed a negative impact of C2T2 compared to C0T0 on tiller height (54.4 v. 70.6 cm) and weight (2.42 v. 3.22 g) as average over cuts and years. The NPN content was lower in C2T2 (312 g/kg CP) compared to C0T0 (339 g/kg CP). In contrast, the WSC content was higher in C2T2 (90.3 g/kg DM) compared to C0T0 (82.5 g/kg DM). Both ME content and digestibility were increased in C2T2 (9.18 ME/kg DM and 68.2%) compared to C0T0 (8.86 ME/kg DM and 65.4%). Concluding, under increased temperature and enhanced CO2, both functional traits and certain nutrients and their fractions appear to change in orchard grass.

1. Individual birds have a characteristic date for the termination of the egg laying cycle.

2. The date of cessation of production at the end of the pullet year is not a reliable indication of the bird's potentiality in this respect.

3. The longer the birds are retained the greater is the chance of distinguishing the true date.

4. Individual dates for the termination of the cycle occur at so many points throughout the total range (from July to December) that this must either indicate a multiple factor situation or that the genes involved show a considerable range of expression.

The extent of variation in ratoonability was examined in a range of recently bred short-duration pigeonpea [Cajanus cajan (L.) Millsp.] genotypes in 1989/90, 1990/91 and 1991/92 at the ICRISAT Asia Center, Andhra Pradesh, India. Traits with which this variation could be associated were assessed. Differences in the total ratoon yield of two flushes were significant among the genotypes in each season. In a few genotypes, ratoon yield constituted 50% of the total yield, which could be as high as 5·6 t/ha. Total ratoon yield was positively correlated with leaf area index in the last 2 years of experimentation. The relationship of total ratoon yield to main crop yield was significantly positive in 1991/92 only. The results suggest that there is a large variation in ratoonability among short-duration genotypes and that high leaf area retention at main crop maturity appears to contribute substantially to this variation.

In Morocco, sugar-beet seed production represents a new challenge to meet the main breeding programme goals. The identification of a suitable zone for plant vernalization represents a bottleneck for seed production. This study aimed chiefly at evaluating the vernalization aptitude of 18 sugar beet half-sib progenies. Trials were conducted during three selection cycles in a specifically chosen environment. The experimental site of Merchouch is 40 km south-east of Rabat city. Field trials design is according to an open-pollinated experimental block. Yield components and five phenological traits were recorded during the growing cycle and at the plant maturation. The variance analysis showed a significant effect of the selection cycle on the phenological traits and grain yield. The plant cycle duration increased by 10.7 days between the first and the third selection cycles. According to the principal component analysis and the hierarchical clustering, F2, F5, F6, F9, F10, F11, F14 and F15 half-sib progenies are described as long cycle and high grain yield families. Grain yield reached 257.3 g per plant, the duration to maturity 350.6 days and the germination rate 93%. The three selection cycles and the suitability of the site vernalization conditions are potentially effective for seed production progress. Our results are relevant as they established an adequate site for the sugar beet seed production. The half-sib selection is a valuable method for sugar beet germplasm enhancement.

1. Continuous waterlogging and 4 weeks' waterlogging immediately after transplanting produced plants with higher leaf and shoot numbers.

2. There was no difference in the final shoot number between plants continuously waterlogged and those waterlogged for 4 weeks, immediately and 4 weeks after transplanting. The shoot mortality was higher in the continuously waterlogged plants and those waterlogged for 4 weeks immediately, 8 weeks and 12 weeks after transplanting than in those waterlogged for 4 weeks, 4 weeks after transplanting.

3. Continuously waterlogged plants and those waterlogged for 4 weeks, 4 weeks after transplanting, were taller than those waterlogged for 4 weeks, immediately, 8 weeks and 12 weeks after transplanting.

4. Leaf area per bucket, leaf area per shoot and per leaf lamina were higher in continuously waterlogged plants and those waterlogged for 4 weeks, 4 weeks after transplanting, than in those waterlogged for 4 weeks immediately, 8 weeks, and 12 weeks after transplanting.

5. Continuous waterlogging and waterlogging for 4 weeks, 4 weeks after transplanting, increased the physiological age of the plants as evidenced by earlier ear emergence and grain ripeness.

6. Fresh-weight yield, yield of grain and panicle were greater in continuously waterlogged plants and those waterlogged for 4 weeks, 4 weeks after transplanting, than in those waterlogged for 4 weeks immediately, 8 weeks and 12 weeks after transplanting.

7. The critical period for waterlogging in the cultivation of the rice variety studied is 4 weeks after transplanting and waterlogging applied during this critical period for 4 weeks favours higher yield of grain than when applied for the same period earlier or later than this period. Where water supply is limited the plants should only be waterlogged at this period and the soil kept moist throughout the remaining growing period. However, where there is enough water to waterlog the plants for 8 weeks this should be started immediately after transplanting.

P and K fertilizers were applied over a 5-year period to plots that were either cut, individually grazed or communally grazed. Residual effects were assessed in the sixth year when the sward was ploughed and sown with Italian ryegrass. The residual study supported the earlier published inference that (a) P returned to the sward in sheep dung is not an effective P source under field conditions, (b) communal grazing can lead to appreciable transfer of K from one plot to another.

The relationship between rate, spray interval and number of applications of Decis for pest control in cow pea was investigated. In 1978 and 1979, neither the rates nor the interaction effects were significant in grain yield when 12·5 and 25·0g a.i./ha of Decis were applied three times weekly or twice at intervals of 10 or 14 days.

Further trials in 1980 showed that for the contro l of thrips (M. sjostedti), rate, interval and number of applications were significant for samples at 49 days after planting and beyond, suggesting that the residual life of Decis is about 10 days. Three applications were significantly better than two for lowering the population of C. tomentosicollis and the number × interval interaction was also significant. The number, rate and interval were significant without interaction effects for shrivelled pods caused by all hemipteran pests. In all the trials in 1980 and 1981, damage by the pod borer M. testulalis was low. Rate and number × interval interaction were generally significant but no differences were observed in grain yield. However, in 1980 the higher rate and three applications gave better quality crop, resulting from less hemipteran damage.

An analysis of cost–benefit of the trial showed that 12·5 g a.i./ha gave higher returns than 25 g, as did two applications than three, but the trend in the spray interval was less consistent.

Dairy cows were inseminated on the basis of oestrus detection alone (Control, n = 206) or in conjunction with milk progesterone profiles (Experimental, n = 204). Milk samples were taken at 4–5 day intervals to determine oestrous cyclicity and on alternate days (at strategic times) to determine the time of ovulation. Progesterone profiles were consulted routinely as an aid to oestrus detection, and also to identify and aid diagnosis of cows with reproductive disorders. Cycling cows not observed in oestrus were inseminated on the basis of their progesterone profile alone. Animals showing oestrus within 2 days of a progesterone-timed insemination were inseminated again. In Experiments 1 and 2, inseminations were given from Day 42 post partum, but AI was delayed (mean time of 68±1·1 days after calving) in Experiment 3.

The median interval from calving to first insemination was not significantly different between Experimental and Control groups, but the time of conception was earlier (P < 0·05) and the median calving interval shorter (P < 0·05) in progesterone-monitored cows in Expts 1 and 3. In addition, the percentage of cows served within 21 days of the start of the service period was greater (P < 0·05) in Experimental groups in Expts 1 and 2. This was reflected by an increase in the proportion (P < 0·05) of cows pregnant by 85 and 100 days after calving. The frequency with which the interservice interval equated to the length of the oestrous cycle was increased (P < 0·01) by progesterone testing (84·1% and 53·9% in Experimental and Control cows, respectively). Conception rates did not differ significantly between groups, but the number of double inseminations (P < 0·001) and thus the mean number of inseminations/conception (P < 0·01) were greater in progesterone-monitored cows. Conception rate was lower (P < 0·05) in cows that failed to show oestrus, and to the first insemination in double-inseminated cows.

Progesterone testing reduced (by 44–66%, P < 0·01) the number of cows presented for veterinary examination and the mean time of presentation (P < 0·05), and also influenced the diagnosis made.

A method that allows the effect of temperature treatments on plant quality to be quantified is described. The proposed method is based on the analysis of temperature regions for plant quality characteristics and enables an easier and more precise analysis of the influence of day and night temperature on plant growth and development. Plant quality may be evaluated by the combination of any number of plant characteristics. The proposed method can assist growers in determining what temperature regimes are necessary to produce acceptable-quality crops on specified days.

In field drainage waters, Fe(II) can be oxidized to Fe(III), which is precipitated as iron ochre. At a farm near Aberdeen, Scotland, ochre is precipitated both chemically and biologically. The precipitation was delayed using the antibiotic D-threo-chloramphenicol and Cu(II) ions. Iron deposition was delayed on glass slides coated with copper filings. It is suggested that the incorporation and slow release of substances which inhibit ochre formation, from drainage pipe material, would be a valuable method of controlling the ochre problem.

Maize or lucerne silages were fed to two groups of cows in a large dairy herd. Metabolic profile tests carried out during the trial showed that abnormal blood chemistry such as might lead to production disease did not occur in either group.

The results of feed analysis and digestibility trials showed that the two silages provided equal quantities of digestible energy but that the lucerne silage provided more digestible protein than the maize silage. Blood glucose concentrations were similar in both groups of cows but serum urea and albumin concentrations were significantly higher in the cows fed lucerne silage than in those fed maize silage. There was also evidence that lucerne silage provided slightly less available phosphorus but more calcium than the maize silage.

It is concluded that maize silage, as used in these experiments, showed no tendency to lead to production disease, and furthermore the metabolic profile test provided additional information to feed analysis in making this assessment.

This study aimed to quantify a latent variable for body size (BS) in pigs by using five linear body measurements including body length (BL), body height (BH), chest width (CW), chest girth (CG) and tube girth (TG), and also to identify the most associated single nucleotide polymorphisms (SNP) and related genes with BS by using the genomic best linear unbiased prediction (GBLUP) based genome-wide association study (GWAS) or GBLUP-GWAS methodology. To perform a GWAS on the BS latent trait, we used a mixed linear model and identified a total of 53 significant SNPs. Additionally, we found that nine genes, including Rho GTPase activating protein 12 (ARHGAP12), transmembrane protein 108 (TMEM108), T-cell lymphoma invasion and metastasis inducing factor 1 (TIAM1), ras homologue gene family member B (RHOB), POU class 4 homeobox 1 (POU4F1), follistatin-related protein 4 (FSTL4), cellular communication network factor 2 (CCN2), beaded filament structural protein 2 (BFSP2) and attractin-like protein 1 (ATRNL1) were associated with the BS trait in pigs. These genes are involved in several biological processes, including the regulation of anatomical structure, morphogenesis, the regulation of cell size and growth. The results suggest that the identified SNP and related genes may play important roles in regulating the growth and development of pigs. The results imply that these genes could be promising candidates for further exploration of the underlying mechanisms of body size variation. Furthermore, the findings have significant practical implications for enhancing the efficiency and profitability of pig farming through genetic selection.

The work aimed to evaluate the effect of lactic acid bacteria, natamycin and hexanoic acid on the fermentation quality, aerobic stability and in vitro digestibility of total mixed ration (TMR) silages containing water bamboo sheath leaves. The treatments were as follows: (1) no additives (control, C), (2) lactic acid bacteria (L), (3) natamycin (N), (4) hexanoic acid (H), (5) lactic acid bacteria + natamycin (LN), (6) lactic acid bacteria + hexanoic acid (LH). Silos were opened and silages were evaluated to assess fermentation quality, aerobic stability and in vitro digestibility. All TMR silages were well-preserved as indicated by dominant lactic acid content, low ammonia nitrogen/total nitrogen, trace propionic acid and negligible butyric acid contents. All additives improved the fermentation quality and in vitro digestibility, evidenced by higher lactic acid/acetic acid ratio, lactic acid, acetic acid, water-soluble carbohydrate contents and lactic acid bacteria count, and lower pH, aerobic bacteria and yeast counts. The LN had the highest lactic acid, acetic acid, lactic acid/acetic acid ratio, in vitro gas production and in vitro digestibility. During aerobic exposure, the LN silage had the highest lactic acid and acetic acid contents, and the lowest pH among all TMR silages. The LN and LH prolonged aerobic stability, reaching 85.5 and 81.5 h, respectively. The LN is recommended to improve the fermentation quality, aerobic stability and in vitro digestibility of TMR prepared with water bamboo sheath leaves.

The results of a preliminary investigation on this subject, in which single plots were used, which were published in 1921, tended to show that the following inferences, in respect to the relation of size and type of tuber-set to crop, might be drawn.

1. The size of the crop varied directly with the weight of the set up to a certain point, viz. 2 ozs., the crop then sinking slightly to a more or less constant level, whilst the weight of the set increased.

Bleasdale & Nelder (1960) refer to several models which have been used in studying the relationship of yield and density in crop plants and indicate that they regard as most satisfactory the equation:

where ω = yield/plant, ρ = number of plants/unit area and A and B are constants. The estimation of the constants for any given case is a very unattractive arithmetic exercise requiring a fairly large number of observations and a tedious iterative calculation; Nelder (1961) has discussed the least squares fit with the equation in the form

which may readily be derived from (1) by the substitutions

The data in the present case do not justify attempting this process but some progress can be made by the substitutions

by means of which it is easy to derive from (1) that