H—34

PLANT-BREEDING AND SEED-PRODUCTION Breeding for resistance to black root-rot was advanced another stage. Several trial plots were set out on infected areas in comparison with commercial varieties and some lines proved very promising as regards both resistance and type of leaf. Samples of leaf have been kept for determination of quality. In breeding for resistance to mosaic some lines have proved highly resistant but are still not of the desirable flue-cured type. They have been further back-crossed to their flue-cured parents. A start has been made towards breeding for resistance to verticillium-wilt. The bulk of the seed for the commercial tobacco crop is produced by the Station. The policy is still to distribute seed from selections made from imported seed and once tested for performance and trueness to type. Current requirements are being met and a satisfactory reserve of seed maintained. VARIETIES Harrison's Special 215 maintained its place of high yield combined with good quality. Special 400 was of high quality but did not yield as well, and produced a high proportion of laterals. Delcrest, a new Canadian variety, proved the most resistant to black root-rot, and also had the highest proportion of bright leaf, but the leaf was of the narrow type not favoured by growers or manufacturers. Three lines out of eleven received from Virginia proved promising, and were included for further trial. Two varieties from South Africa proved very susceptible to black root-rot and produced very narrow leaves, as also did an Australian variety. In a trial of Burley varieties on black root-rot infected soil the varieties Ky. 33 and Ky. 34 from Kentucky, and Haronova and Harmony from Canada, proved highly resistant compared to the susceptible local variety. These varieties also yielded well on non-infected soil. FIRE-CURED TOBACCO This type is imported into New Zealand for blending into certain mixtures. A further area of varieties from the United States of America was grown this season, the crop making good growth and looking very promising both for yield and quality. It has been harvested and is at present being cured. KILNS AND CURING Work with the small experimental kiln was continued. It is proposed to build a full-sized kiln, designed by the Dominion Laboratory, in time for operating next season. A group of three experimental curing-cabinets in which temperature and humidity can be accurately controlled and recorded was installed. Some work was commenced on the effect of varying temperatures and humidities on the curing of tobacco leaf and on the quality of the cured product. EXTENSION AREAS Three plots of tobacco were grown in the Takaka Valley this season, two being on the sites of last season's experiments and one on new land. Stormy weather conditions again damaged the leaf, although not as severely as last season. At Marahau some experimental plots were laid down in order to investigate an obscure soil condition. On a Moutere area a trial was carried out embodying different levels and types of nitrogen.

86