Herbage Plants.-The work outlined in the previous report is in every detail being continued and developed on more and more critical and intensive lines. The question of "ecotypes" is assuming added importance as the investigations proceed and this is particularly so in the case of cocksfoot, red clover and white clover. Largely with a view to the better understanding of this problem the Director of the Station during the year under review spent several months in New Zealand and Australia Much valuable information was obtained and arrangements were made for the collection of material in respect of both cocksfoot and white clover from New Zealand in particular.

In connection with the work on hybridization and especially in relation to wide crosses it has become necessary to undertake cytological studies. During the year the chromosome number has been established for cocksfoot, meadow fescue and tall fescue.

In so far as general grassland problems are concerned, a new and hopeful feature of the work is connected with the development of a technique for accurately gauging the effect of the grazing animal on the sward, and for establishing with precision the degree of preference shown for different species and for different parts of the grasses and clovers. By this means it is hoped to throw important light on a number of difficult matters connected with the management of grassland and with factors affecting the persistency and aggressiveness of herbage plants : persistency and aggressiveness being the two points always kept in the forefront in relation to all the breeding work in progress. The work on soil germination and early establishment, although not completed, may be said to have been brought to a practical conclusion as far as pure cultures are concerned. The evidence so far obtained has decided significance in relation to the drawing up of seeds mixtures. The experiments in progress with reference to competition between the several species in conjunction with the earlier work will help largely to elucidate a number of seeds mixture problems.

Cereals. The sixth trial with pure lines of Hen Gymro wheat supports, in general, results previously obtained, and indicates that high-yielding lines of this variety can be produced.

result of this sixth trial, the number of pure lines has now been further reduced, while two of the most promising are again this year under trial on a field scale.

Largely as a result of this work the importance of losses due to bunt is being closely studied investigations have been started with a view to try and breed a Hen Gymro type of wheat showing marked resistance to this disease.

Hybridization and selection, with a view to the production of a good white winter oat and a stiffer strawed oat of the Radnorshire Sprig type, are now sufficiently advanced to warrant the confident hope that final success will follow upon these endeavours. The results of investigations on the inheritance of immunity to crown rust have been successfully continued.

The improvement of the grain in Avena strigosa by means of hybridization and by selection of pure lines is being proceeded with. The pure lines, which have been considerably reduced in number, show great variation in yield of grain, yield of straw and earliness of ripening. Trials at high elevation agree in general with those conducted at the Station.

Lunde, an oat of Norwegian origin, has again justified its great promise for soiling purposes.

The response of standard oat varieties to environmental conditions is being extensively examined both at the Station and at other centres where extreme variation in growth conditions may be expected. This work has been greatly facilitated by the setting up of a sub-meteorological station at one of the hill farms in a district where trials are largely conducted.

Oat diseases under investigation are mainly the loose and covered smuts.

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General. Further results on the effect of length of day upon growth, flower production, chemical composition and yield have been obtained and the work is being continued. In this connection it is interesting to note that the results have been turned to increasingly practical account for inter-crossing plants which normally flower at very different dates.

In breeding work with red clovers it is important that one and the same plant may be used for various purposes and in different places, but, unfortunately, cuttings do not readily "take." The effect of various treatments of the cut surfaces upon adventitious root development continues to be investigated with promising results.

In addition to the Director, Professor R. G. Stapledon, M.A., the authorised graded staff of the Institute for 1926-27 was one principal assistant, assistant, one senior assistant senior assistant and three junior

assistants.

The sums included for this station in the general grants from the Development Fund to the Ministry were:

Academic year, 1st October to 30th September.

Scottish Society for Research in Plant Breeding.

Scottish Plant Breeding Station-Corstorphine, Midlothian. The Scottish Society for Research in Plant Breeding was formed in 1921, and plant breeding experiments were commenced at the Plant Breeding Station, Craigs House, Corstorphine, in the same year.

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The aim of the Society is to establish a thoroughly equipped Station and to promote the discovery and the creation of such new and improved races of the leading crop plants as are best suited to Scottish conditions. The work at the Station is directed towards practical ends, but it should be noted, however, that a certain amount of attention has to be given to problems not of direct practical importance.

The methods employed at the Station to obtain improved types of plants are in the main :

(a) Collection and classification of suitable living material. (b) Isolation of pedigree strains (pure lines).

(c) Comparative trials of varieties, pedigree strains, &c. (d) Hybridisation (crossing) of pedigree strains, varieties and species.

The crop plants on which experiments are being carried out are Oats, Potatoes, Herbage plants (Perennial Ryegrass, Cocksfoot and Timothy) and Swedes. The breeding work is steadily progressing; methods are being developed and improved, and gradually an increasing number of new varieties and selections will be available for field trials.

In the following section of this report space permits of reference being made to the work with herbage plants only.

Grasses. The chief object of the work on grasses at the Plant Breeding Station is to isolate improved pasture strains of Perennial Ryegrass, Cocksfoot and Timothy. As a preliminary step towards reaching this object, plants of various types of Perennial Ryegrass, Cocksfoot and Timothy have been selected from amongst populations of plants growing on uncultivated ground in many different districts. These populations are referred to as "wild," and some of them possess characteristics suggesting superiority as pasture plants over those of a cultivated population; they are more leafy, very much later in flowering, and have a more spreading habit of growth. As there is a wide range of varieties or strains amongst the material already collected, breeding from the most promising plants in the best populations is affording ample opportunity to secure what appear to be desirable grazing types of these grasses.

Preliminary investigations have been made concerning the mode of pollination in the different species of grasses referred to above, both under natural and under controlled conditions. It has been found in Perennial Ryegrass and in certain other agricultural grasses that self-sterility and partial self-fertility are very

common.

Self-Sterility. For the experiments on self-sterility ten inbred populations of Perennial Ryegrass were used, and on an average 150 flowers on 200 plants were self-pollinated. The results showed that a high degree of self-sterility occurred. Two inbred populations were used for cross-sterility experiments, and approximately 1,000 flowers were crossed by hand. In the great

majority of crosses a very high percentage of flowers set seed. No seeds, however, were obtained from certain combinations, although the crosses were repeated and the male and female organs were proved to be functional in compatible crosses. This purely experimental work which has been in progress for the last three years has now advanced sufficiently far to indicate methods of breeding suited to the experiments at the Plant Breeding Station with cross-fertilised grasses.

Breeding. The results of experiments carried out have indicated that less variability in type is likely to occur by breeding from individual plants from "wild" local populations than from plants selected from cultivated strains. The "wild" The "wild" populations have almost always produced progenies containing a high proportion of desirable grazing types. In general, these types are leafy, and in some the late-flowering habit is pronounced. Various types of Perennial Ryegrass have been compared, and there is reason to believe that the plants best suited to pasture purposes are those which develop tillers from the stem joints, below or at the ground level; with types in which the tillers arise at a higher point of the shoot, the effects of close grazing may retard or possibly inhibit any further development of the plant.

Two clones of Perennial Ryegrass, which had been multiplied vegetatively, were interplanted at a fairly high elevation on the Lammermuir Hills in order to determine the possibility of obtaining seed of this species from such a hill district where there is natural isolation, i.e., isolation from other plants of Perennial Ryegrass. The two plants were known to be crossfertile at the Plant-Breeding Station. The results of the experiment there in 1926 were that while about 50 per cent. of the flowers set seed, the total amount of seed obtained was very small. In the previous year, 1925, only one of the plants set seed.

Two clones of Perennial Ryegrass which were breeding true, at least as regards certain essential and similar characteristics, were interplanted at the Plant-Breeding Station and seed obtained. A certain amount of natural isolation occurred through their flowering much later than the ordinary Perennial Ryegrass in the surrounding area. This seed has been sown in small field-trial plots for observation under conditions approximating to those obtaining in a pasture.

In addition to the Director, Mr. W. Robb, three assistants were employed, one of them being in charge of the potatobreeding experiments at the Sub-Station at Ainville, Kirknewton, Midlothian. This Station has a substantial endowment, provided partly by Scottish farmers and partly by the Scottish Board of Agriculture. The Commissioners recommended a grant for each of the financial years 1925-26 and 1926-27 of such sum (not exceeding £1,100) as, when added to the interest derived from the capital grant of £22,500 made by the Board of Agriculture, would be equivalent to two-thirds of the Society's

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expenditure. The grant is paid through the Board, and any additional grant required to meet a deficit on approved expenditure is made by the Board of Agriculture from its own Parliamentary Vote.

National Institute of Agricultural Botany.

The aim of the Institute is to improve the yield and quality of farm crops. It is organised for this work in three main

branches :

(a) Crop Improvement Branch, which affords facilities. for the field testing of old and new varieties of agricultural plants and the introduction of new ones produced by plantbreeding institutes and other organisations and individuals.

(b) Official Seed Testing Station managed by the Institute on behalf of the Ministry of Agriculture.

(c) Potato Testing Station, Ormskirk, where wart disease immunity and susceptibility trials, and yield and maturity trials, are carried out, and varieties growing on the trial plots are examined for "synonymity."

Besides the headquarters' buildings and trial ground at Cambridge, there is a Potato Testing Station at Ormskirk, a farm at St. Ives, Hunts., and sub-stations for field trials in Shropshire, Hampshire, Norfolk, Essex and Devon. For trials in other districts special arrangements are made with agricultural institutions or individual farmers.

Crop Improvement.-The series of trials which were undertaken in 1924-5 have been continued in 1925-6 on the same lines at Cambridge and the five sub-stations. They are being repeated in 1926-7 for the third successive year. At the end of that time enough information will have been obtained, as regards the majority of the varieties tested during the period, to allow their replacement in the trials by other new or established varieties. The trials in 1925-6 dealt with the following varieties:

Wheat: Squarehead's Master (Control variety), Swedish Iron III, Cambridge Browick, The Fox, Little Joss, Wilhelmina, Yeoman II, Weibull's Standard (a new Swedish variety), and a new wheat bred by Mr. J. C. Brown.

Winter Barley Squarehead Winter (Control variety), Plumage Archer 1924, and two new barleys from Dr. Beaven.

Winter Oats Grey Winter (Control variety), Black Winter, Bountiful and Marvellous.

Winter Beans: Ordinary Winter Beans (Control variety) and two new varieties from Dr. H. Hunter.

Spring Barleys: Plumage Archer 1924 (Control variety), Archer, Sunrise, Spratt-Archer, Archer-Goldthorpe. Standwell, New Cross, one new variety from Dr. Beaven, and