Certain vegetable seeds show such a marked loss of viability on storage that they are generally useless after 1–2 years storage under average commercial conditions; the most valuable seeds which store particularly badly are parsnip, onion and carrot. Storage experiments were therefore designed and set up to show the effect of the following factors on the viability of the seeds:

(a) The water content as determined by the humidity of the atmosphere in which the seeds were stored.

(b) Atmospheric conditions, viz. ventilated air, unventilated air and nitrogen.

(c) Temperature.

Phenological and aerobiological research into major crops is of great value in adapting traditional processes to the new conditions prompted by global climate change. Data on flowering phenology and airborne pollen have also proved useful for harvest forecasting purposes. The current paper reports on an agrometeorological study carried out in the Montilla-Moriles Protected Designation of Origin area (Córdoba, southern Spain) in 2015 and 2016. The study focused on four grape cultivars produced at seven local vineyards (Pedro Ximénez, the most widely grown in the area; Verdejo; Muscat blanc à petits grains; and Chardonnay, which has been recently introduced). Phenological observations were performed on a weekly basis using the Biologische Bundesanstalt, Bundessortenamt und Chemische Industrie scale adapted for grapevine. Airborne pollen concentrations were monitored using one Hirst-type volumetric sampler and seven passive samplers. Airborne pollen was mainly detected in vineyards during inflorescence emergence and flowering. Year-on-year differences in climatic conditions led to differences in airborne pollen levels. The main variables affecting pollen concentrations were dew point and temperature. The life-cycles recorded here were shorter than in temperate climates but longer than in tropical climates. In terms of flowering period, the cultivars studied here were classed as ‘early cultivars’. Data obtained using local passive samplers located directly in the vineyard confirmed that the airborne pollen concentrations recorded by the volumetric sampler were representative of the study area.

In a former communication (1) a study has been made of the influence of the stage of lactation on the yield and quality of the milk, and in the following paper a similar investigation has been made of the influence of the age of the cow on the same factors.

Mackintosh (2) finds a gradual increase in yield up to the 4th or 5th lactation period, and a decrease after the 7th or 8th; thus a heifer calving at 2¾ to 3 years gives 60–70 per cent. of the amount it will produce as a mature cow; after the second calf it gives 80 per cent. and after the third 90 per cent. Tocher's results (3) show an increase from 85 per cent, of the maximum yield at 3 years to a maximum at 7½ years, and a subsequent fall to 90 per cent. at 12 years of age.

1. An experiment was carried out from 1 August 1953 to 31 July 1955 to compare strip grazing with rotational grazing on the basis of the total animal production obtained from dairy cattle on irrigated pasture.

2. The same overall stocking rate was used for both treatments. Herbage surplus to grazing requirements at any time was conserved as hay and fed back to the appropriate group of cows at the end of the grazing season.

3. The aim was to manage the area under each technique as efficiently as the technique permitted.

4. The average production from the rotationally grazed group during the main pasture season of 260 days was 8740 lb. milk per acre (including 354 lb. of butterfatand 766 lb. of solids-not-fat) and from the strip-grazed group 8867 lb. milk per acre (including 358 lb. of butterfat and 766 lb. of solidsnotfat).

The average weight of pasture nutrients utilized per annum by the rotationally grazed group was 5887 lb. starch equivalent per acre and by the stripgrazed group 5896 lb. starch equivalent per acre.

None of the treatment differences in animal production was significant.

5. The differences between the results of this experiment and those obtained by other workers are discussed.

The phenotypic, genotypic and environmental correlation coefficients were calculated for 13 morphological and tuber quality characters, 17 of 78 possible combinations were found to be significant. Tuber yield was positively associated with average tuber weight and with total tuber dry matter per plant. Average tuber weight was negatively associated with number of tubers per plant and with most of the quality characters. The indices for selection for tuber yield were computed using the yield components and yield only. It was observed that the selections based on tuber yield itself are likely to be superior to those based on yield components. However, an index involving the yield components and the yield was found to be most efficient.

Among the tuber quality characters, percentage tuber dry matter showed significant positive association with the percentage alcohol-insoluble solids (AIS) and with the percentage of starch in fresh tubers, and a negative association with the percentage of protein in tuber dry matter. The associations between percentage of starch in fresh tubers and the percentage of starch in tuber dry matter, between percentage of starch in AIS and the percentage of starch in tuber dry matter and between percentage of protein in fresh tubers and the percentage of protein in tuber dry matter were also found to be significant and positive.

To increase tuber yield it is necessary to break the negative linkage between its two components. High total tuber dry matter per plant can be brought about by selecting for high tuber yield. For the improvement of tuber quality together with tuber yield, the selection for yield based on a large number of tubers is likely to be useful.

(1) Grassland has been classified as natural and semi-natural; both classes have been further sub-divided according to the botanical composition of the herbage in relation to habitat (pp. 27–36).

(2) The plants which colonise natural grasslands have been called primary indigenous species; and those which come in without being sown and contribute largely to the herbage on semi-natural types have been designated secondary indigenous species (p. 37).

The effects of three planting patterns (ridge, furrow and flat) and three population densities (31800, 47600 and 71400 plants/ha) on the growth and yield of three sunflower hybrids, Flamme, Upsolveraflor and Isostar, were investigated at the Sultan Qaboos University Experiment Station, 1990–93. Seed and oil yields were higher in the ridge-planted sunflower than those planted in furrow or flat patterns, the order being ridge > flat > furrow. However, the magnitude of yield differences between ridge-planted and flat-planted sunflower was not sufficiently high to compensate for the additional labour and materials required for making ridges. Based on this, planting in the flat was recommended. Although increased population density resulted in taller plants, lodging was generally low and did not constitute a serious problem. Biomass/plant, head weight, receptacle weight, head diameter, number of seeds/head and 1000-seed weight decreased with increase in plant population density. Flamme had its highest seed and oil yield at 71400 plants/ha, while Isostar attained its highest yield at 47600 plants/ha. Isostar outyielded the other two hybrids and appeared to have a potential for commercial production in a desert climate.

In order to examine whether high yield of maize could still be maintained at high plant densities by creating an ‘erectophile canopy’ through artificial defoliation of laminae, an experiment at Pantnagar, India, was made on the effect of density, stage and degree of defoliation in two divergent seasons, Kharif (rainy) and spring, of the year 1972. The defoliation treatments were either partial (clipping off the apical half of individual leaves) or complete (full leaf removal) and were imposed at three stages of plant growth, namely when 10 or 16 leaves were fully open or 12 days after silking. These treatments were applied at two plant densities, 60000 and 90000 plants/ha.

Grain yield of maize increased significantly with the increase in population density in the spring season. The trend was diametrically opposite in the Kharif season. Defoliation at the 10th fully open leaf stage produced more grains than defoliating 12 days after silking, which in turn produced more than defoliating at the 16th fully open leaf stage, when plants were in full bloom. Increase in the degree of defoliation at the latter two stages of plant growth reduced grain yield, the effect being more at the 16th leaf stage. However, 50% defoliation at the 10th leaf stage increased grain yield in the Kharif season.

The percentage protein content of grain declined with the increase in population density whereas increase in degree of defoliation increased the grain protein content. Higher protein content of grain was recorded in the spring than in the Kharif season. The leaf protein decreased as the plants neared maturity, especially at the higher degree of defoliation treatments.

Sucrose and reducing sugars declined significantly with the increase in degree of defoliation. The reduction in sucrose was large enough to account for the reduction in total sugar percentage. Similar trends were observed in the sugar-to-protein ratio.

Experimental conditions and design were described in part I. Separable lean and fat were highly correlated with the carcass and whole body components of protein and ether extract. The carcasses of refed sheep at 45 kg empty body weight (EBW) had about 1 kg less fat and more lean than carcasses from sheep of similar weight which had been continuously fed. Restricting feed intake to 70% ad libitum gave carcasses that had more protein than those from sheep fed ad libitum both during continuous growth and after realimentation.

Sheep that had lost 25% EBW to 26 kg and then were refed to 31 kg EBW had 34% less separable carcass fat than sheep which had been continuously fed to EBW of 36 kg and then had lost weight from that level to 31 kg EBW, and the separable fat was higher in water content than during normal growth (an effect shown consistently in realimented sheep).

Severe underfeeding rapidly reduced bone water but bone ether extract continued to accumulate. After a period of refeeding, bone fat was rapidly mobilized and bone water quickly returned to normal. During early weight loss following food intake reduction, there was a larger decrease in carcass water than expected, and most of the discrepancy could be accounted for by the disproportionately large loss of water from bone and separable fat.

It is concluded that during early regrowth there is a marked stimulus of lean tissue growth and depressed fat synthesis. After this initial period, growth rate of carcass tissues is not greatly different from that found in continuously growing sheep although there is some evidence of a small positive rate of protein growth effect following through to 45 kg EBW in the refed animals. The ratio of muscle gain to fat gain from 30 to 40 kg EBW was 2·23 in realimented sheep and 1·08 during normal growth.

1. In pony mares during oestrus in which a follicle was considered to be sufficiently ripe (thin walled) the intravenous injection of 500 i.u. pregnancy urine extract induced ovulation in nineteen out of twenty-three mares between 24 and 48 hr., in three cases within 24 hr., and in one case between the fourth and fifth days.

2. Dialysed egg yolk as a medium for storage of horse sperm for 24 hr. was shown to give satisfactory results when ovulation is controlled by the above method, so that it occurs within 24 hr. after insemination. Nine single inseminations during one oestrus resulted in five pregnancies.

3. The number of spermatozoa required for successful inseminations is discussed.

4. Means of detecting a sufficiently ripe follicle before injection with pregnancy urine extract are described.

5. It is shown that the duration of oestrus is shortened as the result of pregnancy urine injections.

6. Data is given concerning the time which elapses between ovulation and the cessation of oestrus.

The growth in body weight of 91 stags from weaning to 15 months of age and of a smaller number from 15 months to maturity was examined using observations from a farmed stock kept on hill land. Growth rate in winter from 3 months to 10 months of age was proportional to feed allowed and was 35 % greater than for hind calveskept under similar conditions. Growth rate in the subsequent summer was greater for stags than for hinds in sixout of seven instances. After 15 months of age, stags continued to increase in body weight and their weight thus continued to diverge from that of hinds such that at 87 months the average weight of the surviving nine stags was 132 kg and that of the surviving 47 hinds, 78 kg. It is estimated that the equilibrium weight of stags was 154kg.

Nine field experiments with sugar beet in 1968–70 tested eight amounts of nitrogen fertilizer (0–290 kg N/ha) on a shallow calcareous loam (Icknield Series), on a deep sandy loam (Newport Series) and on a heavy clay loam (Evesham Series). The amount of mineral nitrogen in the top and sub-soils was determined before applying fertilizer and at monthly intervals from May to October in plots given 0, 125 and 250 kg N/ha. The crop on these plots was also sampled at monthly intervals throughout the growing season and the yield and nitrogen uptake determined. The soil analyses indicated that in springs with average rainfall, the leaching losses of nitrogen fertilizer are negligibly small, although there was some evidence that losses may be greatest on sandy loams. In very wet springs such as 1969, with almost double the normal rainfall, losses through leaching are considerable – on average, 40 kg N/ha. Dry-matter yields and response to nitrogen fertilizer differed between the three soils consistently from year to year. On the calcareous loam, neither amount of fertilizer changed the dry-matter yield of roots in any year. The crop on the clay loam needed a small dressing and on the sandy loam a larger dressing of fertilizer for maximum root dry-matter yield. Uptake of nitrogen by the crops usually paralleled the decreases in soil mineral nitrogen although on the clay loam nearly a third of the nitrogen applied could not be accounted for in the soil or plants, suggesting that some denitrification may have taken place. When the amount of nitrogen taken up by unfertilized crops is allowed for, the percentage recovery of applied fertilizer nitrogen at final harvest ranged from 42% on the calcareous loams to 62% on the sandy loams.

Transpiration rate, diffusive resistances, canopy conductances and water potentials were determined at three canopy positions in non·stressed and stressed plants of sunflower hybrid BSH·1 and five other cultivars of sunflower under field conditions. The leaf area (LA) and stomatal frequency (f) was determined at the three canopy positions in field·grown plants and the total number of stomata per plant was calculated as the product of LA and f. These variables were then related to the dry·matter accumulation and seed yield in these cultivars. Cultivars with either a high leaf area or high number of stomata per plant were more productive under non-stress conditions. Under stress conditions, cultivars differed in the extent of change in conductance (g) and transpiration rate at different canopy positions. In the hybrid BSH·1, g was low at all levels in the canopy associated with a higher (less negative) water potential and this hybrid had lower transpiration rates at all canopy levels under stress although the number of stomata per plant was high. Stomatal sensitivity associated with a higher threshold water potential for stomatal closure is discussed as a possible explanation for the higher dry·matter accumulation and productivity of hybrid sunflower BSH·1 under moisture stress conditions.

Flower, pod and seed development were studied in the cultivars Cita-1 and Cita-2 in two field trials in 1985–86, in Ibadan, Nigeria. Flowering within any inflorescence was acropetal. On each plant the terminal inflorescence was the first to flower and, generally, inflorescences developed basipetally. A total of 569 flowers (mean of five plants) opened on Cita-1; of these, 20 were on the terminal inflorescence, 130 on axillary inflorescences and 419 on inflorescences on primary branches. For the 605 flowers (mean of five plants) which opened on Cita-2, the distribution was 19, 161 and 425, respectively.On Cita-1, 158 pods formed on average, of which 7 were on the terminal inflorescence, 33 on axillary inflorescences and 118 on inflorescences on primary branches lower down the plant. On Cita-2, for the 185 pods counted at maturity, the distribution was 8, 43 and 134, respectively. Some 72 and 69% of the total number of flowers which opened on Cita-1 and Cita-2, respectively, were aborted. In both cultivars, 99% of the mature pods were formed from flowers which opened within 24 days of the start of anthesis; the number of pods retained largely determined seed yield. The inflorescences which developed on the primary branches contributed 70% (Cita-1) and 66% (Cita-2) of the total seed yield. Early-formed pods were heavier than those formed later. Individual pods attained physiological maturity 35–42 days after successful pollination of the flower. At physiological maturity of the pod, the seed contained 3·72 % N, 0·45% P and 2·76% K, and the husk contained 1·98% N, 0·16% P and 1·96% K. The majority of open flowers which aborted were produced on primary branches, indicating that the primary branches have the greatest potential for increasing seed yield. A shorter flowering period might ensure greater retention of open flowers.

1. Internal Disease has been found to occur throughout numerous samples of potato of known variety such as for example: “The Sutton Flourball,” “Sharpe's Express,” etc.; similarly, Streak-disease has been found in samples of certain other varieties such as: “British Queen,” “Edina,” “Duke of York,” etc.

2. Well-developed Internal Disease has been detected in very young tubers.

3. The markings in Internal Disease and Streak-disease may or may not form a connected system in the tissue of the potato, sometimes the discoloured areas are quite isolated. The diseased cells can be easily traced to within a few cells of the cork-layer (skin). In Streak-disease they can be occasionally traced right up to the cork or to a slight injury to the surface of the tuber.

4. No trace of a hyphal organism could be found either within the cells or intercellular spaces of diseased tissue. The cells are killed, often retaining their starch in an unaltered condition. If the disease is propagated from cell to cell it takes place without an easily visible deterioration of the cell-wall in the initial stages.

5. Internal Disease and Streak-disease did not spread in store under the experimental condition described.

6. In every experiment samples of potatoes affected with Internal Disease and Streak-disease whether planted in Devonshire or Northumberland produced a certain proportion of tubers affected with these diseases.

7. The diseases in question are frequently complicated by the presence of Phytopthora infestans in the field and Fusarium solani in the pit or store.

The effect of age on attainment of puberty and on seminal characteristics in yearling and mature rams was studied in German Merino, Persian Blackhead and indigenous Native rams living on Rhodesian highveld.

1. Puberty occurred at age and live weight proportional to mature live weight. Well-grown Native lambs ejaculated first at 169 days of age and 46 lb. live weight; Merino lambs when 250 days old and 79 lb. live weight and Persians were intermediate. Onset of sexual maturity was related more closely to live weight than to age, since runts ejaculated first at live weights close to those of well-grown lambs.

Any conclusions drawn from the foregoing results will of course apply only to the necessarily limited range of soils in one county. This range is limited geologically and the Aberdeenshire soils belong largely to the class of light to medium acid soils of low base status. The results for these soils indicate that:

(a) The occurrence of grass sickness is not confined to soils of any particular geological origin.

(b) The range of textural conditions in the soils examined is a wide one covering loams, sands and peaty types with a few moderately heavy soils. There does not appear to be any relationship between soil texture and the incidence of grass sickness.

(c) The soils examined all fall into the class of acid soils and in only a very few—about 5 to 10%—could the addition of lime be considered unnecessary from the general agricultural point of view. As against this there are no striking abnormalities in the ratios of exchangeable or readily soluble cations in the soils, which might serve as a clue to the occurrence of grass sickness. Although little is known of the actual magnesium, manganese and strontium requirements of hay and pasture plants, the range of values covered in the soils examined is sufficiently wide to make it very unlikely that there is any relationship between the incidence of grass sickness and the magnesium, manganese or strontium contents of the soil. In view of the relatively widespread acidity in the soils examined, the possibility of a relationship between the occurrence of grass sickness and soil acidity has to be borne in mind. It would be of value to find out if grass sickness occurs to an appreciable extent on limestone soils, or on soils which have been systematically limed and which have pK values in the neighbourhood of 7.

(d) The majority of the soils are, from the general agricultural point of view, somewhat low in readily soluble or available potash and phosphate, but against this about 30% of the soils have satisfactory phosphate contents and about 20% of the ordinary surface soils and 46% of the top 2 in. samples, in which occur the bulk of the plant roots, have satisfactory potash contents. It does not appear likely therefore that the occurrence of grass sickness is to be related directly to the phosphate and potash contents of the soil. As far as reserves of the common plant foods are concerned there is likewise no abnormality which could account for the disease.

Development of partial inter-specific hybrid (PIH) rice is a promising approach for exploiting inter-specific heterosis between Oryza glaberrima and Oryza sativa. In the present study, the relationship between genetic distance (GD) of parental lines and yield performance of the PIHs was assessed using partial diallel crosses between three indica male sterile lines and 14 introgression lines (ILs) with different fragments of O. glaberrima genes. Twenty two out of the 42 PIHs expressed positive heterobeltiosis (i.e., the Fl hybrid showed superiority over the better parent in the target trait) for panicle number, spikelet number, thousand grain weight and grain yield/plant. The proportion of O. glaberrima genome in the ILs ranged from 0·03 to 0·41, as revealed by 16 informative simple sequence repeat markers. Significant positive correlations were found between the proportion of O. glaberrima genome of the ILs and the GD between the ILs and the three different female parents. Heterosis of spikelet number per panicle in the hybrids was positively proportional with the O. glaberrima genome content of the parental ILs, while that of fertile grain percentage was negatively proportional to the O. glaberrima genome proportion. On average, the PIHs with higher grain yield and highest heterobeltiosis were obtained from the ILs carrying between 0·15 and 0·30 of O. glaberrima genome. The results indicated that a small proportion (<0·15) of the O. glaberrima genome in the ILs might limit heterosis expression of spikelet number per panicle, while a very large proportion (>0·30) of the O. glaberrima genome decreased the grain filling percentage in the PIHs, thus an intermediate range of O. glaberrima genome proportion should be more suitable for breeding heterotic PIHs. The exploitation of inter-specific heterosis between O. glaberrima and O. sativa has potential value for heterotic breeding in rice.

Oestrous activity in local Rahmani and Ossimi sheep and imported subtropical Awassi sheep at different times of the year in Upper Egypt and the effect of continuous exposure to long-day conditions from July till December on this activity was studied in 1986. The three breeds differed substantially in oestrous activity but differences did not seem to be directly related to latitude of origin. Rahmani ewes from the Nile Delta were mostly cyclic all year round; the percentage coming to oestrus each month never fell below 70%. Ossimi ewes originating from mid-Egypt had a very long breeding season; 74% had an anoestrous period of 68·8 days (v. 27% for Rahmani ewes). All Awassi ewes, except one, had an anoestrous period of 96·5 days on average.

Awassi ewes also showed more response to continuous exposure to long days (14 h) than Ossimi ewes, seen in a shorter reaction interval and a greater decrease in the percentage of ewes coming into oestrus (27 and 90% in control and treated Awassi ewes, respectively). The results indicated that changes in daylength, although small in subtropical regions, may be a major factor controlling seasonal changes in reproductive activity in subtropical sheep breeds, the more seasonal breed being more responsive to changes in daylength. The possibility of selection within these breeds for continuous reproductive activity is also indicated.

The objective of the present study was to determine the optimal culling strategy in relation to biological and economic efficiency (BE and EE, respectively) and annualized net revenue (AN) in the Japanese Black cow–calf production system with special reference to the beef quality of culled cows. The herd model focused on two ways of mating: one-mating trial system (ONE) and continuous-mating trial system (CON). ONE assumed that heifers that fail to conceive are culled and cows that fail to conceive are culled at weaning of their calves, while CON assumed that mating continues until all females theoretically conceive. Least square means of carcass data of Japanese Black cows collected from a cooperative farm in Japan were used to estimate the carcass price of a cow by parity and Beef Marbling Standard (BMS) number. The simulation, assuming the current production situation in Japan, indicated that sales of culled cows accounted for 0·10–0·20 of total sales and was an important element in total production. Comparisons between ONE and CON showed that production efficiency in the current situation is higher in CON. The BE, EE and AN were higher in CON than in ONE. The two economic indicators were less sensitive to changes in annual discount rate but highly sensitive to changes in female calf price and BMS number of cows, indicating the importance of considering fluctuations in calf price and potential quality of culled cows’ carcasses when estimating the economically optimal parity of culling. The three indicators derived different optimal solutions even in the same mating trial systems, stressing the importance of choice of production indicators when determining the culling strategy and evaluating animal production.