H.—34

21

Hot-water treatment with regard to smuts provides a means whereby smut-free erops"may'*"be produced, but the doing of this is beyond the ordinary farmer. Thanks to the Canterbury Seed Co., smut-free-barley seed in amounts sufficient for malting requirements is now able to be provided, the work having been done in co-operation with the Station. Loose smut of wheat could also be eliminated in exactly the same way the Canterbury Seed Co. is eliminating barley-smut, and some organization is necessary whereby the necessary nucleus disease-free seed is made available so that certification of loose smut-free wheat could be carried out, particularly with Solid-straw Tuscan. Mycology. Many of the diseases being dealt with by the Mycological Section are of those that are conveyed in seed, and, unfortunately, with many of them it is necessary to secure absolutely disease-free seed before any success in practice can be realized. In order to secure this, much painstaking research is necessary before any application of any results obtained can be put into practice. This work, again, requires the best of controlled conditions, and additional greenhouse accommodation is urgently required. Some noteworthy work, probably leading to rapid application, has, however, been done with regard to club-root. It has been shown that, provided the land is raised, to a sufficiently high pH value, cropinfection on land previously affected is rare. This indicates the great value that lime must play in the final control of the disease. Again, with certain swedes, particularly the variety known as Herning, great resistance to club-root has been demonstrated. The fact, however, that on evenly affected ground some bulbs show far greater resistance than others indicates that selection within the variety may be valuable, and this work has been arranged for. In this review certain phases of the Station's work have been dealt with, the full details being available in the sectional reports, but there are some other matters that must be dealt with. Agronomy Section. The work of this Section falls into three closely associated divisions —(1) The production, by selection, of pure and superior strains of farm seeds other than herbage-plant seeds ; (2) the multiplication and distribution of these and of imported seeds by the Department or in co-operation with farmers ; (3) the certification of the produce of farm crops conforming to certain standards of purity and freedom from disease. (1) Plant Selection Work. Wheat. —This work is undertaken in co-operation with the Wheat Research Institute, and so that there shall be no duplication of the activities of the Wheat Geneticist it embraces nothing but the production of pure and smut-free lines of the standard commercial varieties. The following varieties are under selection : Solid-straw Tuscan, Solid-straw Velvet, Major, Pearl, Marquis, Velvet, Dreadnought, Hunters, Sensation, White-straw Tuscan. The area occupied was about 10 acres, consisting of— (a) Three hundred single-ear selections : (b) Twenty-eight preliminary yield trials of selections made during 1927-28. Replicated eight times these represent 336 plots. (c) Fifty-one large-yield trials of selections made in 1926-27. Replicated eight times make a total of 600 plots. (d) Seed is not reserved from the yield trials (b) and (c), therefore each selection is represented by an increase plot of pure seed. The season's results have been considerably marred by excessive cross-pollination between varieties, and greater precautions will have to be taken in future years. Seed of the following varieties is to be distributed for increase : Velvet, Solid-straw Velvet, Dreadnought, Major. It has been decided that in future all lines of pedigree seed shall be the produce of crops which are of 99 per cent, varietal purity, altogether free of loose and stinking smut, and removed not more than six years from the single-plant stage. Potato. —Potato-selection has as its objective varietal purity and freedom from disease, with particular reference to virus disease. The work commenced in 1927-28 was largely hampered by the lack of material, and of the very large number of tuber units tested out only a few remain. This, however, has given material for distribution this coming season. About 2,000 tuber units have been under trial and sixty-two increase blocks. These are being dug, and comprise mainly those varieties not obtainable outside New Zealand. The search for virusfree tubers became so difficult that during the season 1928-29 a number of varieties were imported from Scotland and Ireland. These proved so far superior to anything obtainable in this country that further supplies have again been imported this season. Of the material imported during 1928-29 some 450 tuber units were planted, and thirty increase blocks in 1929-30. This work is likely to render avail-able this season and next, lines of seed potatoes superior to anything that is available at the present time. Constant rogueing for disease and efficient isolation to prevent reinfection are tlie main difficulties that have to be overcome. Barley. —As a result of work commenced in 1926-27 four smut-free selections are available of each of the standard malting varieties —Plumage, Archer-Spratt, Plumage-Archer, Chevalier, GoldthorpeSpratt —and selections are being made of "Gisborne" —altogether twenty plots of acre each. These will go on to a yield trial next season, and thereafter distributed through the Canterbury Seed Co., with whom co-operation has been arranged.