Two spring wheat varieties, Cardinal and Kolibri, were inoculated with Septoria nodorum Berk and S. tritici Rob. & Desm. at Growth Stages 3, 7, 10.1 and 10.5 of the Feekes' scale. The treatments included single inoculations at each growth stage and multiple inoculations at 2, 3 and 4 of the above growth stages.

Thousand-grain weights of both varieties were reduced by inoculation with either pathogen, S. nodorum causing the largest reduction. Numbers of grain per head in Cardinal were severely reduced by S. nodorum, particularly after the multiple inoculations. In Kolibri, there was evidence of increases in numbers of grain with S. tritici inoculation which nullified the grain size reductions. The results are discussed in relation to compensatory mechanisms and disease tolerance.

Each crop variety has a genotype-specific ability to maintain performance over a wide range of environmental conditions. This ability is usually referred to as the sensitivity or adaptability of a variety. Such an ability is an important property, because farmers naturally want to use varieties which perform well in their own fields. Assessing sensitivity has, however, proved difficult, because of problems involved in defining and measuring the wide diversity of natural environments. These problems often lead to split statistical analyses of trial data or statistical models including explanatory variables with no biological interpretation. That causes ambiguity in statistical inference and prediction. The present study shows how the latest advances in statistical research can be applied to overcome some of these difficulties. A key point is to use the conditional expectation of the yield given the environment as a latent explanatory variable. In this way the predicted yields of different varieties can be estimated at any expected environmental yield level. Discussion is restricted to yield data but similar methods can be applied to other performance characters. The Finnish statutory variety trial data are used to illustrate the methods and the results.

Experiments made for 4 years in the seasonally dry period of the monsoon environment of north-west India showed that the application of farmyard manure (FYM) with the onset of monsoon rains (in early July) was more advantageous for the growth and yield of wheat than its application at the end of the monsoon season in mid-September. Fertilizer N drilled into the soil with the cessation of rains was better utilized by wheat than that applied at sowing in mid-November. A combination of the organic matter and urea was better than their application separately. N, P and K removal by the wheat crop was significantly increased by FYM and urea application. The time of their application influenced the nutrient removal by the crop in the same way as it affected its growth and yield.

The results of a long-term field experiment conducted from 1977 to 1984 on alluvial (Ustochrept) soil of Jalandhar showed positive responses of the crops to N. The responses of potatoes to N were reduced by farmyard manure (FYM), green manure of dhaincha and moong and the responses to the organic manures were also reduced by N. The N responsesof potatoes were, however, not affected by the N applied to preceding maize. FYM was better than the green manures in augmenting total tuber yield, large-grade tuber yield and K concentration in the plants.

The N applied to the potatoes showed significant residual effect on succeeding wheat crops, reducing its optimum dose of N by about 50%. The residual effect of N on wheat was highly correlated with nitrate status of the soil. The organic manures applied to potatoes improved the yield of the succeeding wheat but did not differ from each other.

The fodder crop of pearl millet raised after 7 years also indicated the superiority of FYM to the green manures. There was a build-up of organic carbon, N, P and K in soil and the build-up was maximal with the use of FYM. The application of N had no effect on the organic carbon and nitrogen status of the soil. N improved the availability of P but decreased that of K.

There is little information on rates of protein synthesis in individual muscles in ruminant animals. Skeletal muscle is the largest single tissue and, as such, has a considerable effect on nitrogen transactions in the body. Arnal (1977) found a substantial decline in synthetic rate between 1 and 16 weeks of age in lambs and also observed differences between red and white muscles. Bryant & Smith (1982a) measured synthesis in several muscles of mature sheep and they observed lower rates than Arnal (1977) with little difference between most muscles. Vastus intermedius muscle in the hind leg, however, had higher rates of synthesis than other muscles. Here we report rates of protein synthesis in individual muscles in rapidly growing lambs approximately 12 weeks of age. The major back muscle, the longissimus dorsi, and two hind leg muscles, the vastus lateralis and the vastus intermedius, were chosen for study.

The forage potential of Andropogon gayanus (gamba grass) was assessed in cutting experiments on a low fertility, acid Ultisol in Colombia. This grass recently introduced from Africa outyielded Hyparrhenia rufa, Panicum maximum, Brachiaria decumbens and Digitaria decumbena in various mixtures made up of a single grass and a single legume. A. gayanua performed well as a companion grass with the legumes Styloaanthes guianensis, Stylosanthes capitata and Centroaema sp., while B. decumbena suppressed the legumes planted in these trials during the 2nd year following establishment.

The effects of five stake weights (50, 63, 75, 88 and 100 g) of three cassava cultivars (TMS 30572, TMS 91934 and NR 8083) on the growth and yield of cassava were studied for 2 years (1992/93 and 1993/94) in Nigeria. The leaf area index (LAI), crop growth rate (CGR), net assimilation rate (NAR), leaf area duration (LAD), harvest yield and harvest index (HI) were dependent on the weight of stake planted and were greatest at the stake weight of 88 g (875 kg/ha) irrespective of cassava cultivar. Variations in LAI, LAD and HI of stake weights between 75 and 100 g were non-significant. The profusely branching cassava cultivars, TMS 30572 and NR 8083, achieved greater LAI, CGR, NAR and LAD relative to the sparsely branching cultivar, TMS 91934. The significant growth and yield differences among the stake weights with the optimum at a stake weight of 88 g (875 kg/ha) indicates the need to adopt this stake weight for sustainable and improved growth and yield in cassava production.

In this paper the results are described of experiments on bull sperm cells with the photo-electric device for measuring the ‘motility’, as developed by Rikmenspoel, van Herpen & van Dam (1956).

It was found that the velocity distribution of sperm samples differs only slightly from a Gaussian one. The form of the distribution curve, which is a bit skew, is rather constant between ejaculates. This means that generally the ‘motility’ of a sperm sample can be characterized by the mean velocity of the sperms, the standard deviation of the velocity distribution and the number of cells moving normally. The mean ratio of velocity and frequency of rotation (the ‘speed’ of the screwing movement of the head of the sperm cell) was found to be a less important motility characteristic for most experiments.

The scattering of the above-mentioned properties in various ejaculates were measured, while the sperm samples were all kept in the same conditions. It was found that the mean velocity has a rather constant value.

A linear relationship between the mean velocity of the sperms of a sample and the viscosity of the diluent is found. This holds also for the dependence of the ‘speed’ of the head movement and the viscosity.

The mean velocity of sperm cells was found to increase approximately in a straight-line relationship with the temperature in the range 33–41° C. There were indications that the mean velocity may reach a maximum in the region of 42–45° C.

If sperm samples are stored at 4° C, the mean velocity and the number of cells moving normally is found to decrease exponentially. The decrease of the number of cells moving normally is three to four times faster than that of the mean velocity. Some evidence was obtained that the characteristic time for the decrease of the number of cells moving normally is bull-specific.

1. Each of three litter sister sows was fed one of three levels of crude protein in the diet during two 8-day periods in the fourth and seventh weeks of lactation. The three protein levels were 11, 15 and 19% of the diet on an air-dry basis. The scale of feeding was varied to maintain each sow at constant weight throughout the 8-week lactation period.

2. During two 3-day collection periods following 5-day preliminary periods, intake of nitrogen from the diet and outputs of nitrogen in faeces, urine and milk were measured.

3. The sow receiving the medium level of protein in the diet was in positive nitrogen balance during both collection periods.

4. The major effect of increasing the protein level of the diet was an increase in the output of urinary nitrogen. Neither milk yield nor output of protein in the milk appeared to be affected over the limited period studied.

5. Apparent digestibility of dietary protein was 75% on the low level and 85% on the medium and high levels of intake.

A long-term calcium and phosphorus balance experiment with laying hens is described.

The cumulative balances of calcium and phosphorus over a whole year were seen to be physiologically impossible.

Results from other workers using short term balances could be equally impossible and a similar situation has recently been noted in balance experiments with ruminants.

The techniques employed in the experiment were, therefore, investigated in detail.

Only systematic errors could be responsible and it was found that the most likely source of such errors was (a) the spilling of food on to the floor or into the water bowl, and (b) failure to collect all the droppings.

These errors only become apparent in long-term experiments and are more pronounced when diets containing high levels of calcium and/or phosphorus are fed.

Autumn-sown sugarbeet (Beta vulgaris L.) responses (sugar yield, plant N-uptake and juice quality) were studied in relation to the residual NO3−-N in a soil of southwestern Spain which, for the previous five years (1989–93), had received high N rates, in accordance with conventional fertilization schedules used by farmers in the area. Three different combinations of fertilizers, supplying equal amounts of N, were used during the fertilization period (1989–93): a mineral fertilization treatment (MF, a complex 15N-15P2O5-15K2O) and two organo-mineral fertilization treatments (an olive mill wastewater sludge compost, AC, and a depotassified concentrated beet vinasse, V). All these treatments also received a top-dressing with urea (46% N). A control treatment (C), without fertilization was included for comparison.

During the major part of the beet growing season, the presence of almost four times as much mineral N in the 0·100 cm soil layer of previously fertilized plots (AC, V and MF) than in the unfertilized one (C), led to a significant increase (P<0·05) in total fresh weight yield and N-uptake, but also to a significant decrease (P<0·05) in sugar content and beet processing quality. The time course of NO3−-N concentration in sugarbeet petioles and the evolution of the nutritional state of leaf-blades gave advance information about the final response of the crop to the different fertilization treatments. Besides N, Na was the element which, due to the repeated and high fertilization rates applied, had a major effect in reducing the technological quality of the sugarbeet.

In order to assess relative thermal sensitivity between the day and the night, vaginal temperature (Tv), heat production (HP), heart rate (HR), respiration rate (RR), skin surface temperatures (from which mean skin temperature (Ts) was calculated) and standing time were measured at environmental temperatures (Te) of 23, 28, 33 and 38°C during the day (11.00–15.00 h) and during the night (23.00–03.00 h) using four Holstein heifers. Both Tv and mean body temperature (Tb) were greater during the night than during the day, increased with increased Te, and the rate of increase of both Tv and Tb with increased Te was greater during the night (P<0·05). Estimated mean HP was similar during the night and during the day, and HP did not increase with increased Te. Respiration rate was greater but not significantly different at night compared to during the day, and increased with increased Te. Mean skin temperature was similar between day and night, and increased with increased Te. The amount of time engaged in standing activity was greater but not significantly different during the night than during the day and standing activity increased with increased Te. The results suggest that thermal sensitivity is lower during the night than during the day, and consequently the greater night responses of Tv and Tb, over day responses, are a requirement for the maintenance of heat balance.

Many authors have studied the post-natal growth of cattle (Ecles(7), Feldmann (8), Gärtner (10), Moulton, Trowbridge and Haigh (16, 17), Brody(4, 5), Fischer (9), Schmalhausen(19, 20) and many more).

On the other hand, embryonic growth has been studied only by a few (Hammond (11), Bergmann(1) and a few others), although Maligonoff (14, 15) pointed out the great importance of studying embryonic development.

The principal factors influencing the yield and quality of milk are (1) stage of the lactation period, (2) breed of the cow, (3) interval between milkings, (4) age of the cow, (5) individuality of the cow, (6) efficiency of the milker, (7) temperature and weather conditions, (8) health of the cow, (9) feeding.

A pot culture experiment with 30 Old Alluvium soils was conducted to evaluate the critical Zn concentration in soils and wheat plants for predicting the response to Zn application. The DTPA-extractable Zn (available Zn) in these soils ranged from 0·37 to 4·50 mg/kg soil, and total Zn in the wheat plants of the control pots ranged from 17 to 65 mg/kg wheat shoots. The DTPA-extractable Zn was found to be positively correlated with organic carbon (r = 0·72, P < 0·01), negatively with pH (r = –0·48, P < 0·01) and positively with wheat tissue Zn concentration (r = 0·98, P < 0·01). The Bray's ‘per cent’ yield value was positively correlated with ‘available’ Zn (r = 0·82, P < 0·01) and plant tissue Zn (r = 0·85, P < 0·01). The critical concentration of Zn in soil and plant below which responses to applied Zn may be expected was 0·65 mg Zn/kg soil and 24·5 mg Zn/kg wheat shoots respectively. All the soils below 0·65 mg Zn/kg soil responded to Zn application where the ‘per cent’ response at 5mg added Zn/kg soil ranged from 22·65 to 100·00 with a mean value of 58·24 whereas at 10 mg added Zn/kg soil, it ranged from 13·08 to 97·14 with a mean value of 40·08. Soils above the critical limit negatively responded to Zn application.

The incidence of swayback among lambs in two flocks, previously reported, was reanalysed by a specially developed modification of the probit analysis technique in order to allow for the joint complications of an all-or-none trait and a large number of possible classifications for the animals in each flock. The form of analysis described yields predictions of the probability of swayback among lambs for the given circumstances.

Breed and sire within breed each affected the probability appreciably even when allowance for live weight of ewe and lamb was made. The effects of live weight, though significant in each flock, were not consistent in direction between the flocks. Other significant factors affecting swayback incidence were the manner of rearing the lambs, week of birth, and, in one flock, the sex of the lamb.

Water requirements, total body water (TBW) and water distribution were evaluated in Awassi sheep and Aardi goats of Saudi Arabia. Ten non-pregnant and non-lactating females from each species were individually housed in shaded pens during winter and summer seasons. Each experimental period lasted for 2 weeks; the first week was an adaptation period, followed by an evaluation period of 1 week. Feed and water intake together with body weight were recorded daily. Five animals from each group were used for determination of body water, extracellular fluid (ECF) and plasma volume (PV) using dilution techniques. Urea and sodium thiocyanate were used for the estimation of body water and ECF, respectively, and Evans blue for PV determination. Intracellular fluid (ICF) and blood volume (BV) were calculated. Feed intake was not affected by either season or species. During the winter season, Aardi goats had lower water intake in comparison with Awassi sheep, but water intake increased in all animals during summer. TBW increased during summer in all animals, but with higher values in the Aardi goats. During summer, ECF tended to increase in Aardi goats. PV, expressed as a proportion of body weight, was not affected by season, but it was maintained at higher levels in the Aardi goats irrespective of season. It could be concluded that Aardi goats used water more economically when the ambient temperature was lower but, during the summer when ambient temperatures were higher, they increased their water intake and BW content to a greater extent and stored more water in the ECF compartment compared to Awassi sheep.

Empty body weight and body measurements were made on 142 lambs from Border Leicester × Merino and Merino ewes mated to Dorset Horn rams, grazed at three stocking rates and slaughtered at approximately 32·3 kg full body weight (FBW). Carcass composition studies were made on 58 of these lambs. An approximate doubling of growth rate during the first 6 weeks of life occurred between stocking rates for lambs from Merino ewes. A smaller difference was found in lambs from Border Leicester × Merino ewes. Growth rates of lambs from Merinos were significantly lower at all times from birth to slaughter. Stocking rate, breed and sex effects on growth rate resulted in lambs reaching mean weight of 32·3 kg at 80–150 days.

A three-way analysis of variance was performed on data for all parameters measured using FBW as a covariate. These parameters were of carcass measurements and composition, and of composition of the internal organs. There were no effects of stocking rate on empty body weight, carcass weight, or any carcass measurements. The weight of dry edible meat was depressed at the high stocking rate due to a higher moisture content. The fresh weight of internal organs was lower at the high stocking rate. A number of sex differences were found. Ewes had lighter carcasses and heavier cannon bones; their edible meat had a higher moisture content and higher ash content than wethers. Eye muscle width was less in ewes than in wethers. Internal organs of ewes had a lower EE % and higher CP % than those of wethers. The only breed type differences were in the weights of internal organs and eye muscle widths at the 9–10th and lOth–llth ribs, and age to slaughter.

Two Rhizobium strains were studied for their chemotaxis, nodulation, nitrogenase activity and other endosymbiotic N2-fixing characteristics with two genotypes of Cicer arietinum. Root exudates were found to attract Rhizobium strains. Nodule-specific root proteins (nodulins) and leghaemoglobin were found to be host-range specific between two strains of Cicer Rhizobium. Physiologically active iron content was more important for nodule functioning than total iron concentration of nodules.

The objective of this study was to assess the efficiency of a pedigree intra-cultivar selection, based on widely spaced individual plant performance, in a traditional snap bean (Phaseolus vulgaris L.) cultivar, aiming to restore or even improve the cultivar. The programme started with the target of earliness and yield stability, and was progressively advanced with the target of seed shape uniformity. Two parallel pathways were followed: under greenhouse conditions (four generations of selection) and under field conditions (two generations of selection). The average response to selection was 2·43–3·15 and 0·13–0·42 pods/plant per generation for earliness and yield, respectively. The coefficient of variability (CV) of earliness decreased from 81·33 to 39·43 % and from 61·31 to 42·51 % for greenhouse and field grown progenies, respectively. For yield, the CV showed a low decreasing rate, and was stabilized at the end-value of almost 28 %. The results were confirmed during two direct evaluation tests. Firstly, the evaluation of 21 families, as individual spaced plants, showed mean values for earliness of 18·99–22·94 pods/plant and for yield of 32·89–33·09 pods/plant. Secondly, the evaluation of improved selections from the greenhouse and the field and of the source cultivar, in a dense stand, showed that all the selections produced high and stable early fresh pod harvest even 53 days after planting, while the control was still at the vegetative phase. The yield of selected progenies was 219–242 % superior compared with source material. Also, seed stocks of all selections were of the normal long shape. Short-seed progenies were excluded from the breeding programme, since they lacked earliness and stability of performance. The results demonstrate conclusively that it is possible to simultaneously improve earliness and pod yield through diminishing plant-to-plant variability.