Since sugar beet was first grown on farms it has been difficult to establish single seedlings at the required spacing because each seed unit was liable to produce a cluster of seedlings. Plant breeders have introduced varieties with monogerm seed and these were used between 1960 and 1962 to see if they led to any savings in labour with hand and machine thinning and to determine the yields of beet after these treatments. The trials described show that, after machine thinning, predetermined final plant populations with 90% of single seedlings were obtained and, when a herbicide was effective in weed control, the labour requirement was about 5% of that required to hand single a crop from multigerm seed. When singled by hand the monogerm varieties required 90 % of the labour needed to single a multigerm crop but the mean yield per acre of the monogerm varieties used was at least six tons per acre less than that from a commercial variety with multigerm seed.

Although the infertility of the subsoil in humid, semi-arid and arid regions has received much attention from investigators in Europe and America, in South Africa, as far as the writer is aware, no such work has been done.

The last issue of this Journal (p. 132) contains a paper by Dr R. A. Fisher on the effect of Silica upon the growth of Barley at Rothamsted, which begins by stating that his data “show conclusively that the view previously rejected that the silicate acts by making available to the plant the actual reserves of soil phosphates must be regarded as strongly established.” Twice elsewhere Dr Fisher states that this erroneous conclusion of previous investigators is due to the fact that they had considered only the proportion of phosphoric acid in the ash and had overlooked the increase in the total phosphoric acid in the crop. As Mr Morison and I were the previous investigators in question I turned to our twenty-three-year-old paper with some curiosity to ascertain the grounds for this magisterial dismissal of our conclusions, for my remembrance of the subject did not tally with the opinion Dr Fisher attributes to us. Still less do I agree now that I have re-examined our original paper.

One hundred and eighty triple test cross families arising from three barley crosses (C 164 x EB 1556, BG 25 x NP 21 and BH 15 x RD 103) were grown in two blocks of a randomized-block design in saline-alkali soil prepared in micro-plots. The families were evaluated for number of days from sowing to heading, plant height, number of tillers per plant, ear length, number of grains per ear, 100-grain weight and grain yield per plant. The cross BG 25 x NP 21 showed epistasis only for number of days toheading and number of grains per ear; in contrast, epistasis was present in all traits in BH 15 x RD 103. In cross C 164 x EB 1556, epistasis was detected for plant height, ear length and number of grains per ear. Thus, epistasis appears to be related to specific cross combination. The ‘j and l’ type epistasis was more pronounced than the ‘i’ type. Early generation selection may be used for number of days to heading which Exhibited epistasis marginally with preponderance of additive gene effects, while for the remaining traits selection should be deferred till an advanced generation.

Over a 12-day fattening period the use of maize in the poultry-fattening ration has no detrimental effect on the consistency of the body fat.

When fattening is rapid and live-weight gains are satisfactory, the type of fat deposited in the bird is harder than that laid down on a normal ration containing mixed cereals and a protein supplement.

The skeletons of most of a group of lame buffalo from an area around Pasir Puteh and of some of a group of similarly lame animals from an area S.W. of Pasir Mas were poorer than those of a control group from around Kota Bharu. Analyses of blood and liver indicated that the defective mineralization of the skeleton was caused by a shortage of phosphorus rather than of calcium or copper.

Evidence for a relationship between lameness and the quality of the skeleton was not strong and further study including a feeding experiment is needed to establish the validity of this.

1. The findings presented in two previous papers on the yields of volatile fatty acids, obtained by the action of rumen liquor in the artificial rumen, from fresh grass, dried grass and the water-soluble and water-insoluble separates of the latter, have been amplified by a consideration of the acids similarly obtained from specimens of chemically prepared crude fibre and cellulose, from four of the dried grass specimens.

2. The proportions of different volatile fatty acids from grass crude fibre and grass cellulose resemble those obtained from cellulose powder, propionic acid being produced in greatest relative yield.

3. A general review of these latter findings, in relation to those already presented, has been given.

The ability to detect and measure water stress accurately is critical for optimizing crop production. The Crop Water Stress Index (CWSI), the linear relationship of the difference between foliage and air temperatures as a function of the air vapour pressure deficit, is one widely used method. Under well-watered conditions, a ‘baseline’ is derived that is crop specific and presumed fairly constant, despite differences in development and physiology. This study reports changes in the baseline of the CWSI for lucerne crops not subjected to water shortage over 3 years. Studies of lucerne in California from April 1986 to October 1988 used the CWSI to plan irrigations. It was necessary to re-establish the baseline periodically throughout the experiment. In the first year it was similar to that reported in the literature, but in the second year it had a statistically significant steeper slope and higher intercept. In the third year, the regression equation was similar to that in the first year. The changes in the baseline are thought to be a result of crop age rather than year-to-year weather fluctuations. The baseline needs to be determined periodically as the crop matures, to ensure accurate interpretation of plant water stress.

One hundred and sixty-eight wool samples were collected from commercial flocks of Karadi sheep raised in the five provinces of northern Iraq. The wool characteristics dealt with were staple and fibre length, crimps, fibre diameter, medullation, fibre strength and elongation.

The results showed that the Karadi wool is a long type of carpet fleece with average staple and fibre lengths of 19·3 and 23·5 cm, respectively. It had an average fibre diameter of 48·1 μ and contained 19·45 % medullated fibres. The number of crimps per 2 cm was 2·4. Average fibre strength and elongation were 24·8 g/5 cm and 31·8 % respectively. Phenotypic correlations between wool traits were studied.

An observed positive correlation between tuber sprout growth in store and yield and tuber weight was due to the association of short sprouts with small tubers (less than 75 g). Sprout growth in larger tubers appears to be unaffected by tuber weight.

1. Series of yields (root weight) of twenty-five plots of Barnfield mangold field are analysed into components representing (a) deterioration, (b) slow changes other than steady deterioration, (c) annual fluctuations. The two first of these components are exhibited graphically from 1876 to 1930.

2. Yields are well maintained on the dunged strip, except for the last few years. This falling off does not appear in the other strips, and may be due to a falling off in the quality of the farmyard manure in the last five years.

3. On the strip receiving farmyard manure and on that receiving superphosphate the plots receiving nitrate of soda yielded more highly than any others; on the strips receiving complete minerals, and on that receiving superphosphate and potash, the two plots receiving rape cake in one case, and sulphate of ammonia and rape cake in the other, gave higher yields than nitrate of soda; on the strip receiving no minerals the result is intermediate, there being little to choose between these three plots. On all strips sulphate of ammonia is the least satisfactory of the four nitrogenous dressings tested.

The gross energy of forages can be classified into three fractions, namely the unavailable fraction, the digestible energy fraction and the potentially digestible energy (PDE) fraction. The PDE fraction can only be made available by appropriate treatment and supplementation (Pigden & Heaney, 1969). In young forages the PDE fraction is relatively insignificant, but as the plant matures, the PDE fraction increases very rapidly. By treating matured forages with delignifying agents, increased nutrient digestibilities have been demonstrated Chandra & Jackson, 1971; Wilson & Pigden, 1964), but no significant improvement on the voluntary intake was achieved unless the treated material was supplemented with a source of nitrogen (Donefer, Adeleye & Jones, 1969). While Zafren (1960) used ammonium hydroxide (NH40H) as the treatment alkali, with the claim that the ammonium acetate resulting from the neutralization of the excess alkali could serve as an extra source of nitrogen in the treated straw, other investigators (Donefer et al. 1969) have adopted the method of supplementing the treated straw with a source of nitrogen. Since the efficiency with which dietary nitrogen is converted to microbial nitrogen in the rumen has a considerable influence on the efficiency the animal as a whole, studies herein reported were carried out to test the effectiveness with which rumen micro-organisms utilize different nitrogen sources in degrading cellulose in vitro.

Growth and visceral organ weights of male guinea fowl (Numida meleagris) given different levels of oxytetracycline have been studied in two experiments. In the first experiment 0, 5·0, 10·0, 15·0 and 20·0 mg oxytetracycline per kg diet were given to male guinea fowl from day 1 to 12 weeks. Body weight showed significant (P < 0·05) increases with incremental levels of the antibiotic up to 10 mg/kg diet. No further increases in growth were recorded with supplementation above this level. There were no treatment effects on the gizzard, lungs and male reproductive organs. Only the heart, liver and intestine weights were significantly (P < 0·05) affected by the treatment, and then only at the highest (20 mg/kg) of the inclusion rates examined. A second experiment was conducted to find out if the growth response obtained with 10 mg/kg oxytetracycline could be produced with a smaller dose. This was achieved at 6·6 mg/kg.

Damage to barley grain cv. Golden Promise was induced in the laboratory by putting seed at 8·7, 14, 18, 22, 26 and 35% moisture content (MC) through a mechanical laboratory thresher for 10, 20 or 45 sec. The extent of visible external damage was greatest at 8·7 and 14% MC with reduced and similar levels of damage after handling at 18–35% MC. At moisture contents up to and including 26%, seeds could tolerate extensive mechanical damage with little effect on seed quality. Seed germination and seedling vigour were, however, reduced after handling at 35% MC despite similar levels of external damage to those seeds handled at 18, 22 and 26% MC. Samples of grain of cv. Triumph produced by whole-crop harvesting included mainly slightly damaged seeds with little effect of harvest moisture content, which ranged from 22·5 to 44%, on the incidence of damage. Seed germination and seedling vigour increased when seeds were harvested at progressively lower moisture contents, with the largest increase between 36% MC (56% germination, 6·1 vigour rating) and 29·5% MC (94% germination, 7·8 vigour rating). The seed quality of whole-crop harvested seed at 29% MC was similar to that of combined seed harvested at the same moisture content. It is suggested that 30 % is the maximum harvest moisture content at which commercially acceptable seed may be produced by the whole-crop harvesting method.

In a study of two coarse-wool breeds (Awassi and Hamdani) the birthcoat and adult fleece were sampled from six body positions. Mean fibre diameter, mean fibre length, mean staple length and the percentages of fibre types were studied in relation to the birthcoat fibre type arrays.

The birthcoat of the two coarse wool breeds showed only plateau and saddle fibre type arrays. In Awassi lambs, plateau arrays were all P3 type whereas in Hamdani 28·6% of the plateau arrays were Po and the rest were P3 indicating a stronger base in the latter. S/P ratios, calculated from fibre types, were 2·22 and 2·27, at birth, and 3·56 and 2·93 at 4–8 weeks of age, in Awassi and Hamdani respectively. Awassi birthcoats showed more precipice within the CT group than those of Hamdani and plateau arrays were more endowed with the precipice than were saddle arrays.

A composite sample from the back and mid-side, in Awassi, and from the back and britch, in Hamdani, was found to be most representative of the birthcoat fibre types.

In the adult fleece of the Awassi breed, the mean fibre length following plateau arrays exceeded those following saddle arrays.

In Hamdani, the saddle arrays developed into coarser fibres in average diameter than those of plateau arrays whereas in Awassi no difference occurred. Awassi plateau arrays were followed by higher within-staple variability in distribution of fibre length than were saddle arrays, whereas in the distribution of fibre diameter there was no difference. In Hamdani, however, saddle arrays were followed by slightly higher within-stable variability in both length and diameter than were plateau arrays.

Birthcoat samples that had a transition in the CT group or had saddle array developed into adult fleeces with greater frequency of normal distribution in both fibre length and diameter, within staple. Adult fleeces that showed frequent bimodal distribution of both diameter and length, within staple, were those with birthcoats that had a precipice in length, or in coarseness and length, within their CT group or those with birthcoats that had plateau arrays.

Carcass measurements were made on 24 Rambouillet lambs of different live weights but of the same age, and the lambs divided into 3 groups of 8 according to live weight. Group I, with the lowest mean live weight, had the lowest dressing percentage, relatively heaviest head and feet and lightest pelt, while group III, with the highest mean live weight, had the highest dressing percentage, the relatively lightest head and feet and the heaviest pelt of the three groups.

Group I contained the lowest percentage, and group II, of medium live weight, the highest percentage of muscle, while the relative weights of bone and fat tissue were similar. Group III contained the highest percentage of fat tissue and the lowest percentage of bone. The differences in the relative weights of the edible internal organs between the three groups were not significant.

Testis weight was relatively much greater in Group III than in the lighter animals. While dressing-out percentage increased with body weight, the increase was not equally distributed between fore and hindquarters. Hindquarters were relatively larger in group II than in group I; but the forequarters accounted for the greater part of the differences between groups II and III.