Introduction Of Flue-cured Tobacco Varieties

Experiments and demonstrations of different flue-cured tobacco varieties, KRK22, KRK23, KRK26, KRK28, T27, T29 and T62, introduced from Zimbabwe were conducted in this paper for screening for high-quality features based on the analysis of the agronomic traits, economic traits, disease resistance, leaves appearance quality, physical characteristics and chemical composition, and to enrich our country's tobacco germplasm. Results were as follows:1. the isolation and quarantineFlue-cured tobacco varieties, KRK22, KRK23, KRK26, KRK28, T27, T29 and T62, introduced from Zimbabwe were grown in isolation and quarantine. Test results showed that KRK26 carrying tenuis (brown spot pathogen) and Fusarium spp (black root rot disease pathogen corrosion etc), which not belong to our quarantine. KRK26 and KRK28 carried unknown fungus, which also not belong to our quarantine. Some varieties carried tobacco powdery mildew. Test results also showed that the tobacco downy mildew sporangia and spores stems were not found in anyone of the varieties.2. the analysis of agronomic traitsThe stem girth and pitch of KRK22, KRK23, KRK26, KRK28, T27, T29 and T62 were all larger than that of K326 (CK). The main vein of all varieties except for KRK22 and T27 was rougher than that of K326. The lumbar leaf length of KRK26, KRK22, and T62 was longer than that of K326, but as for KRK23 and T29 was shorter than K326. The lumbar leaf width of all varies was wider than that of K326. The leaf color of all varieties except for T62 was not as green as K326. The single leaf weight of T62 and KRK26 was larger than that of K326. The plant geometry of KRK22, KRK23 and KRK28 was similar to K326, which like a tower, but T27, T29, KRK26 and T62, compared with tube-type.3. the analysis of economic traitsThe yield of all varieties except for KRK23 and KRK22 was higher than that of K326 (CK), in which T29 was the highest, followed by KRK26. For the tobacco leaves output, T29 and KRK26 higher than K326, and others lower than K326. 4. the analysis of leaf appearance qualityThe maturity of all introduced varieties closed on that of K326 (CK). The KRK28'leaf color and luster not as good as K326, other varieties'closed on K326. All introduced varieties' leaf structure was looser than K326, and the leaf thickness was thinner than K326. The leaf oil of K326 was less than that of KRK26, closed on that of T27, and more than that of other introduced varieties. On the whole, the leaf appearance quality of KRK26 was best in all introduced varieties, followed by KRK22, which closed on K326.5. the analysis of disease resistanceKRK22 showed resistance to TMV, moderate resistance to root-knot M. incognita, moderate susceptible to brown spot, and susceptible to black shank. KRK23 showed resistance to TMV, moderate resistance to root-knot M. incognita, moderate susceptible to brown spot and black shank. KRK26 showed resistance to black shank, moderate resistance to root-knot M. incognita, and moderate susceptible to brown spot, and susceptible to TMV. KRK28 showed resistance to brown spot, moderate resistance to black shank and root-knot M. incognita, and susceptible to TMV. T27 showed moderate resistance to brown spot and root knot nematodes, moderate susceptible to TMV and black shank. Overall, the resistance of the five introduced varieties to the four major diseases closed on K326.6. composite evaluationsIn summary, KRK26 showed strong growth vigor, uniform maturity of green leaves, and resistance to major diseases. It had higher yield, output value and average price. And its flue-cured leaf appearance quality was better than other introduced varies, which look mostly orange, ripe, strong luster, more oil, moderate thickness, flexible, and fine loose leaf tissue. Its ratio of stem to raw flue-cured leaf was about 25%. KRK26 is a variety with high availability in tobacco industry, and it is suitable for extension and application in modern tobacco production.