ALBERT

Description: The object of this experiment was, in the first place, to see whether, with cotton experiments, there was an advantage in planting a larger number of seeds per hill than the customary number of three; and, in the second place, to see the effect of the interaction of time of thinning with varying numbers of seeds per hill.In cotton breeding work, where trials of new strains have to be carried out as soon as sufficient seed is available, it is important to conserve seed in all possible ways. At the same time it is necessary to plant sufficient seed to give a full and even stand for all strains.In experiments carried out in 1936–7 and 1937–8 stand counts, made soon after germination, showed the advantage of the higher seed rates in obtaining a quick and full stand. Later counts and final counts at harvest showed a considerable evening up, although the two-seed treatment proved unreliable, giving the lowest stand in both seasons.Plant height and weight records, made during both seasons, showed that plants from the larger hills were drawn up much more rapidly than plants from the smaller hills. This rapid elongation in stem height proved, from weight figures, to be at the expense of lateral development, weak and leggy plants being produced in these hills. The ten-seed treatment showed up particularly badly in this respect, the yield figures showing that the plants never recovered from this early deleterious effect.The six-seed treatment, whilst giving a quick and excellent stand suffered to a certain extent from the same defects as the ten-seed treatment. If thinned early they tended to fill out and become more comparable with plants from the three-seed treatment, but when thinning was delayed they never caught up and final yield suffered adversely.

Description: 1. The results of three uniformity trials with a U4 cotton at Barberton are reported. Two of these trials, carried out in a dry year, gave yields in the region of 400 lb. seed cotton per acre; the third, in a wet year, yielded over 1100 lb. per acre.2. Results from the three experiments agreed closely in essential details regarding size and shape of plots.3. In all three cases the percentage standard error per plot decreased rapidly as the plot was lengthened, but tended to increase slightly as the width of the plot was increased.4. The standard error increased as the block size was increased by the addition of more plots, indicating the desirability of keeping the number of strains in a variety trial as low as possible.5. With plots of the same shape the smallest plots were the most efficient, while with plots of the same size the efficiency increased as the plot shape became longer and narrower.6. Two fertility contour maps are given, which illustrate a general patchiness in yield common to cotton crops in the Barberton district.7. Details of the types of plot used at Barberton are given, together with the reasons for their adoption.

Description: The effect of applying a nitrogenous fertiliser to wheat at seven different times and three rates, was studied in pot culture. It was found that the later the time of application the smaller was the increase in the yield of total dry matter and of straw. The increase in the yield of grain, on the other hand, was constant for the first six times of application, the last of which was made on May 25, but a later application made after ear emergence produced no increase.Analysis of the grain yield showed that early application produced its effect by increasing the number of ears per plant. Later applications caused a smaller increase in ear number, but also increased the number of grains per ear and 1000-corn weight. There was no evidence of a critical time for tiller formation such as has been postulated by Doughty and Engledow.The increase in total nitrogen uptake was equal for all times of application, but the ratio of nitrogen in grain to nitrogen in straw and chaff was greater, the later the time of application.The writer wishes to thank Messrs A. M. S. Clarke, G. T. Detlefsen and S. A. W. French for much help with the experimental work, and Mr R. G. Warren for making the nitrogen determinations.

Description: 1. A comparison is made of Δ for the blood of sheep with Δ for the contents of the stomach compartments. It is suggested that the approximate identity of the two sets of values is best explained by the view that absorption takes place from the compartments.2. A variation of 0·570–0·630 is recorded for Δ for the blood of sheep.

Description: 1. The effect of low-temperature treatment on some varieties of wheat, barley and oats has been found to be profoundly affected by the time of sowing of the treated grain.2. Winter sowing showed the least vernalisation effect, while in the spring the stimulative action became more pronounced as far as earing acceleration is concerned, as the sowing was made progressively later. This was particularly marked in winter varieties.3. Developmental studies of the control and vernalised plants showed the stimulative action on early growth and growing point development in the winter varieties.4. Tiller counts on control and vernalised plants of three winter wheat varieties demonstrated the fact that each variety was stimulated to earlier tiller production, but in two of the varieties this resulted in a reduction of surviving ears at harvest.

Description: An account is given of the results of two series of field experiments carried out at Rothamsted and Woburn in the years 1926 to 1936 on the effect of nitrogenous fertilizers on wheat. In the first series a comparison was made of the effects of early (March) and late (May) top-dressings, and in the second series a range of times of application from sowing to the end of May were tested.At Rothamsted, the increases of yield of grain produced by the nitrogenous fertilizer were small and rarely significant, but they were greater at Woburn. On the average of all experiments, the effect of the fertilizer on yield of grain was independent of the time of application. In individual years, variation in effectiveness between times of application was found, and this was correlated with the amount of rain falling in a short period after the time of application. At Woburn, the effectiveness of the fertilizer decreased with increase in the amount of rain falling immediately after the application of the fertilizer, but at Rothamsted the effects were less clear and appeared to be in the opposite direction.The effects on straw yield were relatively greater, and more consistent, than those on grain yield. A greater increase of straw yield was produced by early top-dressing (January–March) than by application at the time of sowing, and the increase declined steadily the later the time of topdressing. Shoot height was increased by the nitrogenous fertilizer, and varied with time of application in a similar manner to straw yield.

Description: 1. The discrepancy between the results obtained by various workers concerning the inheritance of earliness or the time of ear emergence in cereals, suggests that this character needs further elucidation physiologically before genetic analysis can be properly undertaken.2. A study of the ear emergence characteristics of varieties when grown under varying conditions indicates that the expression of this character is very much affected by the growing conditions, and the physiological basis must be understood before the various expressions of earliness and lateness are appreciated. It is therefore suggested that the genetic analysis should be conducted in conjunction with a physiological analysis and with a proper consideration and understanding of the effect of environment.3. A series of crosses involving parental forms differing in time of ear emergence, and in some cases belonging to different physiological groups, has shown how differences in genetic behaviour can to some extent be correlated with the physiology of ear emergence of the parents.4. In one cross involving similar types, no evidence of segregation or large genetic difference was obtained. In two crosses involving larger differences of similar types, evidence for a single major factor difference was obtained. In other crosses between different physiological types, and an unstable form, more complex genetic results including transgressive inheritance were obtained. Still other crosses superficially suggested a 3: 1 ratio in the F2, but the presence of a certain amount of transgression, and the behaviour of the F3, pointed to a more complicated relationship.5. Two crosses involving different physiological types were studied in the F1 and the F2 when sown at different times in the spring by dividing the progenies into separate portions. It was shown that the behaviour of the F1 and the F2 of the same cross was materially affected by the sowing time.

Description: 1. The post-weaning growth of 135 litters has been analysed with a view to determining the relationship of certain arbitrary subdivisions with each other. For this purpose, the weight increases during three periods of 28 days have been denned in two ways—first, by age, the periods being 10–14, 14–18, and 18–22 weeks, and secondly, by weight, the periods beginning at 40, 80 and 120 lb. and continuing as before for 4 weeks.2. When the periods are defined by age, the mean increase per pig per litter is affected by weaning weight, but not by litter size (Table III). The variability of the individual increases becomes greater as the pigs become older and heavier (that is, passing from one period to a later one), but less within a period as the rate of growth increases (Table IV). It was not affected by litter size.3. The distribution of individual weights became increasingly skew with age. This is regarded as a graphical illustration of the fact that while absolute rate of growth is increasing, initially small animals must fall farther and farther behind (Graph 3).4. The correlations between the average litter increases in different periods were calculated for litter sizes 6–11. In general, the coefficient for periods 1 and 2 was about 0·4, and for periods 2 and 3 about 0·6 (Table VI). This is interpreted to mean that, when judged by results over the whole time under observation, litters with a high correlation between the increases in weight during short periods are not properly comparable with those with a low correlation. By this method, differences in rate of growth having an important influence on carcass quality may be obscured.

Description: The effect of rainfall, sowing date and yield on the percentage of nitrogen in the barley grain of certain representative plots on Hoosfield is studied.All these factors are shown to have marked effects. The farmyard manure plot differs from the others, both in mean percentage and in the effects of rainfall and yield.Changes in variety appear to have had little apparent influence, but there is a progressive decrease in the percentage of nitrogen which cannot be accounted for by changes in any of the above factors, and which may well be due to varietal improvementComparison is made with the results of the similar study on the permanent barley plots at Woburn.

Description: Experiments were made in 1936 and 1937 on barley plants grown in pot culture, to determine the effect of shading the ear or the shoot after ear emergence on dry weight and nitrogen content.It was found that after ear emergence the ear and the shoot (leaves and stem) make approximately equal contributions to the assimilation of the whole plant. In the 1936 experiment 28% of the final dry weight of the ear was accounted for by assimilation in the ear itself, and in the 1937 experiment, 19%. These are minimum estimates, for assimilation must have been proceeding in the ears during emergence, before the shading treatments were applied. The results agree well with similar estimates of the extent of assimilation in the ear made on wheat by other workers.The effects of shading on the amount of nitrogen present in the plant at harvest were somewhat variable, but they were always small compared with the effects on dry weight. Shading tended to reduce the amount of nitrogen in the ear, but as the dry weight of the ear was reduced to a much greater extent, - nitrogen as percentage of dry matter in the ear was increased. It is concluded from this result that translocation of nitrogen compounds to the ear is not closely dependent on the amount of the concurrent increase in dry weight of the ear. It appears that the approximate constancy of nitrogen percentage in the ear and the grain throughout development is a consequence of the particular conditions prevailing during normal growth in the field.The experiments showed that 20–30 % of the dry weight of the whole plant was added after ear emergence, suggesting that climatic conditions during this late stage of growth is of considerable importance in determining the final yield.The authors wish to thank Miss J. Hellyer for carrying out many of the determinations of nitrogen content, and Mr S. A. W. French for assistance with the statistical computation.