Although salt injury in plants is due to both osmotic and specific ion effects, little is known about the reaction of rice plants to salinity under increasing sodium adsorption ratios (SAR) in the growth medium. Therefore, a glasshouse experiment was conducted to study the effect of four levels of salt concentration (20, 40, 60 and 80 m-equiv/1 with respect to the sum of Na+, Ca2+ and Mg2+) and four levels of SAR (2, 25, 50 and 75) on growth and mineral composition of rice cvs IR 2153-26-3 and IR 26. The results show that as salt concentration increased, dry-matter yield and percentage water content of shoots decreased regardless of the variety. The rate of decline with salinity was most pronounced under low SAR and in the salt-sensitive variety IR 26. With increase in SAR, the yield, percentage water content and concentrations of Ca, Mg, and K in shoots and roots decreased, but the effects were more marked at the lowest salt concentration and in IR 26. Variety IR 2153-26-3 showed greater tolerance, maintaining a higher concentration of Ca and higher Ca/Na and K/Na ratios and a lower concentration of Na and Cl in the tops compared with IR 26.

The degree of salt injury in rice seems to depend not only on salt concentration but also on SAR in the growth medium whilst salt tolerance is associated with tolerance for both high salt concentration and high SAR. Therefore, in studies on screening rice varieties for salt and sodium tolerance, the interactive effects of SAR and salinity must be considered so as to ensure greater adaptability by the varieties recommended for salt-affected soils.

The average serum T4(D) of nine non-pregnant buffaloes was 5·5 ± 1·4 μg/100 ml. It increased slightly to 6·2 ± 4·2 μg/100 ml in 37 6–7 month pregnant buffaloes. Nevertheless the difference was not significant. When the pregnancy reached 8–9 months, the T4(D) was 9·0 ± 3.8μg/100 ml which was significantly higher than that at 6–7 months (P < 0·01). At full term (9–10 months), T4(D) decreased to 3·6 ± 2–6 μg/100 ml which was significantly lower than that at 8–9 months (P <0·001).

In 1 month post-partum buffaloes, the average T4(D) was 5·1 ± 3·4 μg/100 ml, while T4(D) of 1-month-old buffalo calves was very high, i.e. 13·6 ± 3·2 μg/100 ml.

The total serum T3 (RIA) of late-pregnant buffaloes decreased markedly from that of 8–9 month pregnant (P< 0·001). At 1 month post-partum, T3 rose to 143·4 ± 33·0 μg/100 ml which was significantly higher than that at late pregnancy (P < 0·001). The mean serum T3(RIA) of 1-month-old buffalo calves was relatively high, i.e. 281·0 ± 106·2 μg/100 ml which was significantly higher than 143·4 ± 33·0 ng/100 ml of their darn buffaloes (P < 0·001) at the same period of time.

The RT3U values of 6–7 (35·9 ± 4·2%) and 8–9 (34·7 ± 2·0%) month pregnant animals were highly significantly different from 31·1 ± 3·1 % of the full-term pregnancy (P < 0·001).

A strain of Rhizobium isolated from the root nodule of lentil was caused to produce mutants and screened on a medium of pH 4·5. Five mutant colonies of Rhizobium were isolated from lentil which differed in growth over a pH range 4·5–7·5. Strains differed in their growth in acidic and calcareous soils and also in their effectiveness of N fixation.

The weights of components of the alimentary tract were recorded in 55 swamp buffaloes and 51 zebu cattle slaughtered at Bogor in West Java. These were related to hot carcass weight (HCW) and slaughter live weight (SLW), the latter being calculated from locally developed regressions relating live weight to chest girth. Huxley's (1932) allometric equation was used in its logarithmic form as the basis for covariance analyses of the data. A stepwise regression analysis was also undertaken using a linear model relating HCW and gut component weight to species, sex, age and slaughter condition with SLW as the independent variable.

There were significant differences in dressing percentage between buffaloes (38·1 %) and zebus (44·8%) at 340 kg SLW and these were due to species differences in full gut weight rather than weights of other non-carcass components. The allometric growth coefficients for total gut, or gut component, were generally higher in buffaloes than zebus, but the differences were not statistically significant. Together with other published data, these observations suggest that the gut contents may contribute more to the increase in live weight of buffaloes than in zebus.

At the same SLW or HCW, the buffaloes had the heavier weights of full and empty total gut, full and empty reticulo-rumen and total gut contents. At the same total empty gut weight, buffaloes had the heavier empty reticulo-rumen. It was suggested that Indonesian swamp buffaloes and zebu cattle fed on village-type low-quality diets may also differ in the rate of development of their alimentary tract and this could have implications for their comparative nutritional physiology.

The energy and water balance for Bedouin goats before gestation and at different levels of production was worked out. Both gross energy and total water intake were linearly related to their milk production. High producing animals consumed twice as much food (up to 1256kJ/kg body weight/day) and three times more water (290ml/kg body weight/day) as non-lactating ones.

The conversion coefficient of digestible energy to energy in milk ranged from 34% at peak lactation to 25% at the end of the period. No mobilization of tissue was observed even at peak lactation. Black Bedouin goats thus demonstrate ‘superior dairy merits’ throughout their entire lactating period.

Water requirement of a lactating Bedouin goat was lower than reported for other ruminants and amounted to 2·5 l/kg milk produced. This ratio was maintained whether over 2 l of milk was produced or only 0·5 1.

Compared with goats before gestation, lactating Bedouin goats ‘economize’ both their energy and water metabolism and were highly adapted to maintain production in the adverse desert environment.

Experiments were made between 1977 and 1979 to investigate the possibility of raising potato yields by mixing together cultivars having different growth patterns. The experiments also included mixtures of unsprouted and sprouted seed of the same or different cultivars. In the first experiment (1977) Pentland Crown was mixed with Arran Pilot, Red Craig's Royal or Désirée and the binary mixtures (1:1) compared with the pure stands of each. Yield of tubers from the mixtures did not differ significantly from the mean of two components planted alone at wide or narrow spacing of the seed tubers. Two experiments with identical treatments (1978) included mixtures of Majestic and Désirée and of each cultivar with unsprouted and sprouted seed. Mixtures (1:1) yielded more tubers than the mean of the two components planted alone and at final harvest in one experiment unsprouted and sprouted Majesties gave 7·6 t/ha more than the mean of these and 6·9 t/ha more than the more productive culture (P < 0·05). Similar differences were obtained in the second experiment.

In the final experiment (1979) the degree of sprout development at planting time was varied in the cultivar Majestic. Short or long sprouted seed was mixed with unsprouted seed and long sprouted Désirée was also mixed with unsprouted Majestic. Mixtures of the unsprouted cultivar with either long sprouted Majestic or Désiré exceeded, significantly, the mean yield of components planted alone by 4·1 and 5·8 t/ha, respectively, at a high level of fertilizer. As a mean of three experiments the mixture of sprouted and unsprouted Majesties yielded 6·26 t/ha more tubers than the mean of the components and 4·27 t/ha more than the higher yielding component in pure culture. Better light interception due to higher leaf area duration and a more persistent leaf canopy appeared to produce these effects.

Mean progesterone concentrations were measured in the peripheral plasmas of Merino and Border Leicester × Merino ewes which were fed from day 2 to day 16 after mating on rations designed to provide twice maintenance (2 M), maintenance (M) and one quarter maintenance (¼ M) of food requirements. Mean plasma progesterone concentrations were consistently higher in the ¼ ewes than in the M or 2 M ewes whether they had two corpora lutea (CL) and two embryos surviving or one CL with either one embryo surviving or no embryo surviving, and tended to be lower in the 2 M than M ewes. It is concluded that there is an inverse relationship between levels of nutrition and progesterone within an oestrous cycle in ewes.

The concentrations of adenosine 5′-mono-, -di-, and -triphosphate (AMP, ADP and ATP) in sheep digesta were measured by a new bioluminescence method. ATP in rumen digesta varied with time after feeding and diet, and most markedly according to the size of the population of ciliate protozoa: the ATP content of rumen digesta from ciliate-free sheep was less than a quarter of that of faunated animals receiving the same diet. The adenylate energy charge (EC) (ATP + ADP/[ATP + ADP + AMP]), an indicator of metabolic activity, was high (0·77–0·94) in all rumen samples, but did not appear to be as useful a measurement of activity as ATP alone. As digesta passed along the alimentary tract, the ATP content decreased progressively, from 0·9–2·2 μmol/g dry matter in the rumen to 0·5–1·0μmol/g in the abomasum and duodenum, 07middot;03–0·08 μmol/g in ileal digesta and 0·01–0·02 μmol/g in faeces. EC also tended to decrease, further emphasizing the large decrease in microbial activity which occurs in the hindgut.

As a result of the treatment of made whole-crop barley silage with antimicrobial agents which are specifically inhibitory to fungi or bacteria, it was shown that the subsequent aerobic deterioration was essentially caused by yeasts. These microorganisms were instrumental in the rise in pH, the increase in temperature and the loss of dry matter observed. The filamentous fungi, like one group of bacteria (the streptomycetes), apparently had no part in the process. Bacteria, such as the lactobacilli and particularly proteolytic bacteria, may have had a role in the terminal stages of deterioration, although it was considered more likely that the yeasts again were involved.

The whole-crop wheat silage employed in this work was stable in air, a factor attributed to the combined antimicrobial effects of butyric acid present and the relatively high dry-matter content.

In three experiments the effects of population density, spread in time of seedling emergence and variation in seed size on carrot plant-to-plant root-size variation were investigated.

In the first experiment, coefficient of variation, c.v., of root dry weight was only 27–33% when using uniform growing conditions, graded seed, low population density and synchronous seedling emergence (i.e. over 3–11 days). Allowing asynchronous emergence (i.e. over 8–21 days) increased the c.v. to 32–37%, whereas increasing population density from 25 to 400 plants/m2, but maintaining synchronous seedling emergence, produced a c.v. of 57–73%. Asynchronous emergence combined with high population density increased the c.v. even further to 79–97%. Spread in time of emergence was associated with 5–48% of the plant-to-plant root-size variation. Thus asynchrony of seedling emergence was a source of plant-to-plant root-size variation and this effect was magnified by high population density, but other sources of variation were also important. Statistical analysis showed that the effects of these other sources of root-size variation were no greater in populations where emergence had occurred over only 3 or 4 days than in those where emergence had occurred over 3 weeks.

There was no effect on root-size frequency distribution in a second experiment in which the spread of seedling emergence was truncated from 19 to 14 days by spraying paraquat onto the first seedlings to emerge from field plots.

In a third experiment seeds 1·6–2·0 or 1·0–1·25 mm in diameter were grown in pure or mixed populations under conditions similar to those of the synchronous emergence high-density treatment of Expt 1. Storage roots derived from the large seeds weighed 38% more than those derived from the small seeds. Thus differences in seed size caused some of the root-size variation not already linked with different seedling emergence times. However, the c.v. of root dry weight from all the plants in mixed seed population was not greater than the c.v.s of root dry weight of either of the pure seed populations.

Chick pea Rhizobium strain RG3 was treated with 30 μg/ml of N-nitrosoguanidine and two mutants isolated were resistant to 2000 μg phorate/ml yet retained the capacity to form nodules. On the basis of number of nodules, their dry weight, N2ase activity, total pyridine nucleotides and active iron contents, mutant strains G11 and G26 were found to be equally effective with and without phorate and resulted in significantly greater grain yield.

Ten Scottish Blackface ewes from each of three lines, a line selected for hairiness, a line selected for a fine fleece, and an unselected control, were fleece and skin sampled in April, June, September and December, during their 6J year life-span on the hill.

Fleece weight differed between individuals and between lines, and declined by 4% per year from 1·5 kg at 1 year, to 1·3 kg at 6 years. Fleece grade was inadequate as a method of denning fleece differences between the lines.

The height of the spring ‘rise’ in growth in April differed between years, and between lines, declining 2 mm a year from 26 mm at 1 year. Staple length was greatest in the Hairy group and least in the Fine group (P < 0·05). Growth in length was faster between September and December (autumn) than between April and June (spring). Staple length decreased by 14 mm a year.

The lines differed significantly (P < 0·05) in mean fibre diameter but not in modal fibre diameter. There was a highly significant decrease in diameter from summer to winter, ranging from 20% in the Fine line to 31% in the Hairy line, the greater decrease in the Hairy line being attributed to loss of medulla.

The selection had between 1954 and 1972 changed the S/P follicle ratio of 3·0 in the control to 2·8 in the Hairy line and 3·2 in the Fine line. Most seasonal follicle inactivity occurred in April, December came second, and June invariably had more follicle inactivity than September. The control line had the greatest values of primary follicle inactivity and the Fine least. Among the secondary follicles the Hairy line had most inactivity, and the control line least. Maximum primary fibre medullation occurred in either June or September, and medullation was at a minimum in December or April.

The activities of some enzymes that regulate the gluconeogenic-glycolytic pathway were measured in sheep liver during late pregnancy, at three stages of lactation and after the lambs were weaned. Of the gluconeogenic enzymes, glucose-6-phosphatase and phosphoenolpyruvate carboxylase activities were unchanged throughout pregnancy and lactation and were similar to the values for non-breeding ewes. The activity of fructose diphosphatase increased 2 times and that of pyruvate carboxylase increased 5–7 times during late pregnancy and in early lactation.

In the glycolytic sequence phosphofructokinase activity declined by about 50% during lactation. Pyruvate kinase activity declined by about 40% at the end of pregnancy but throughout lactation it was similar to the value for non-breeding ewes. Hexokinase activity was very low in all animals.

Reproductive performance was assessed in a semi-wild Boran cattle herd living on a grassland ranch in Kenya. Male calves copulated with cows a long time after they were weaned naturally. Up to the age of 16 months they were prevented from mating by adult bulls. Female calves conceived at the average age of 25 months and they had their first calves at about 34 months. Calving interval ranged from 304 to 801 days and averaged 430 days. Calving interval of managed Boran cattle living on the same ranch as the semi-wild herd averaged 494 days with a range of 306–798 days. It is concluded that in herds which are permanently accompanied by adult males artificial weaning and the continuous shift of animals between different cattle groups is not a prerequisite for good reproductive performance.

Dissection data from an experiment involving 12 buffalo, nine ♂Friesian × ♀Egyptian native Baladi (½ Friesian) and nine ♂ Friesian × ♀ ½ Friesian (¾ Friesian) bulls were used to examine the growth and partition of fat between depots and its distribution in different regions of the carcass.

Growth of total dissectible carcass fat (TCF) and its component depots (subcutaneous (SCF); intermuscular (IMF); kidney knob and channel (KKCF)) and total offal fat (TOF) and its component depots (caul (CF); mesenteric (MF); heart (HF)) relative to total body fat (TBF = TCF + TOF) was examined.

Relative to TBF, no significant differences in growth coefficients or adjusted means of TCF, TOF, carcass SCF and carcass KKCF were found between genotypes. Compared with ¾ Friesians, buffaloes had lower rates of deposition of CF and IMF, lower proportion of TBF deposited as MF and a greater proportion of HF.

As dissected side fat (DSF) increased, the proportion of fat decreased in the distal hind limb and neck, increased in the abdominal wall and adjacent ventral part of the thoracic cavity and remained unchanged in the other carcass regions. Fat growth coefficients differed between genotype groups in all carcass regions except the distal hind limb, fore limb and thorax. A posterior-anterior decrease in growth impetus of fat from the loin (b < 1) towards the neck (b > 1) was traced in buffaloes while the growth coefficients within all dorsal cuts in cattle did not differ significantly from 1. Compared with cattle, buffaloes had more of the DSF occurring in the combined expensive cuts with higher SCF: IMF ratio only at the upper limits of fatness considered in the present work.

It is argued that buffaloes relative to Friesian cross-breds have a beef-type fat partition and that characteristic changes in rates of increase in fat depots relative to empty-body weight and in fat in various regions relative to total fat could be related to the increase in Friesian blood.

Two-thirds of the sugar-beet crop in the U.K. receives sodium chloride as part of the fertilizer programme. It is well known that the crop responds profitably on sandy soils which contain relatively little sodium and potassium, and most of these fields now receive sodium chloride. Few crops on clays, silts and organic soils are treated because the value of sodium chloride has never been clearly defined. Thus 36 field experiments were made over the 5 years 1975–9 on contrasting soil types testing five amounts of sodium chloride, 0, 100, 200, 400 and 800 kg/ha, and at two times, either autumn or spring. All the fields chosen were in continuous arable rotations where potassium chloride was applied regularly and nearly all the soils contained more than 120 mg exchangeable K/l.

Sodium chloride (400 kg/ha costing £12) increased sugar yield on average by about 0·2 t/ha (worth £40) on the mineral soils but no crop responded on organic soil. Exchangeable soil sodium concentration was not a good predictive test of which fields would respond but all the large increases in yield were on fields with less than 20 mg Na/1. A few crops responded on soils with 20–40 mg Na/1 but no crop responded on soil with more than 40 mg Na/1. A survey of sodium concentrations in 800 soils showed that most mineral soils contained less than 40 mg Na/1 so it is suggested that all mineral soils regardless of texture should receive 400 kg sodium chloride/ha. Crops on organic soils did not respond to sodium chloride because the soils already contained sufficient.

Autumn and spring applications of sodium chloride on mineral soils gave similar increases in yield provided the fertilizer was not applied just before sowing, when in 2 years it decreased plant establishment. This effect was particularly damaging on clays and silts where it is frequently difficult for other reasons to obtain good seed beds and full establishment. It is concluded that sodium-containing fertilizers should always be applied well ahead of sowing to allow rainfall and cultivations to incorporate them into the soil. On clays and silts it is suggested that they should be applied before ploughing to avoid soil compaction but on sands there may be advantages in post-ploughing application.

In field trials made for two years in the dry period of a semi-arid tract under natural precipitation at the Indian Agricultural Research Institute, New Delhi, overnight seed-soaking of wheat in 0·5% solution of 2-chloro-ethyl-trimethyl ammonium chloride (CCC) prior to sowing increased the grain yield. When treated with foliar application of the chemical in concentrations ranging between 40 and 1000 mg/1, wheat plots yielded better than did the untreated control, but no consistency was noted between the concentrations or stages of their application. The benefit from CCC was due to more root growth, increased stomatal resistance and higher leaf water potential. Treated plants extracted more water from deeper soil layers, increasing their water-use efficiency.

A method is proposed for correcting for competition effects in yield trials by joint regression of plot yields on to the yields of neighbours. Estimation of the variety effects and competition coefficient along with tests of significance are described for a sugar-beet trial with single-row plots where competition effects are assumed to extend only to plants in immediately adjacent rows. For designs which are balanced for neighbouring varieties it is feasible to estimate separate varietal competition coefficients which may be partitioned into components for sensitivity and aggressiveness. An example is given of this extended model fitted to a competition diallel of seven species. While species differed in their sensitivity to competition there was no essential difference between inter- and intra-species behaviour. The model is used to assess comparative varietal performance in monocultures from performance in small plot trials.

(Note that the general term ‘variety’ is used throughout this paper to refer to progenies at any stage in a selection programme.)

The comparative rate of development of Orosius albicinctus Distant was studied on different host plants, sesame, sannhemp, radish, purslane, lucerne, chicory, Indian rape, sugar beet and black gram. The duration of the egg stage was the shortest (7·1 days) on sesame and was prolonged to 12·0 days on chicory. The nymphal duration was again minimal (11·9 days) on sesame and was prolonged to 15·4 days on chicory. The nymphal survival was also more on sesame than on the other hosts. Thus, among all the host plants tested sesame was found to be the best suited host for this leaf-hopper.

S1 maize varieties and varietal hybrids were tested in six locations ranging in altitude from 236 to 1600 m in Cameroon. The grain yields of highland varieties were observed to increase with each increase in altitude while the yields of the lowland varieties decreased with increasing altitude.

The highland × lowland S1 varietal crosses yielded the same as the lowland parental varieties in highland areas and better than highland parental varieties in lowland areas.

Average yields of all varieties per location increased by about 1·1 t/km increase in altitude. Eberhart & Russell's (1966) stability method found no stable variety while Francis & Kannenberg's (1978) genotype-grouping technique found five highland × lowland crosses to be relatively stable.

Number of days from planting to tasselling increased with increasing altitude by about 20 days/km increase in altitude. Highland and lowland varieties performed poorly outside their zones of adaptation because of high incidence of foliar diseases like leaf blights and rusts.