Abstract:

In order to promote the opening of upper tobacco leaves of Nanping flue-cured tobacco, reduce the nicotine content, increase the sugar-base ratio, improve the coordination of chemical components, reduce irritation, and improve the quality and availability of upper tobacco leaves, the main local cultivar Yunyan 87 was used as the experimental material to study the effects of plant growth regulator brassinolide (BL) and forchlorfenuron (KT-30) on the growth and development of tobacco plants and the yield and quality of upper tobacco leaves after toiling, providing technical basis for improving the individual and population structure of tobacco plants, promoting the opening of upper tobacco leaves and improving the availability of upper leaves. Through the field test, a random block design was adopted, 7 treatments were set up, namely CK, spraying water; T1, brassinolide (BL) 5 mg·L^-1; T2, brassinolide (BL) 10 mg·L^-1; T3, brassinolide (BL) 20 mg·L^-1; T4, forchlorfenuron (KT-30) 25 mg·L^-1; T5, forchlorfenuron (KT-30) 50 mg·L^-1; T6, forchlorfenuron (KT-30) 75 mg·L^-1, each treatment was repeated for 3 times. The results showed that spraying a certain concentration of clopifenuron could promote the opening of the upper tobacco leaves and increase the area of the upper tobacco leaves, while brassinolide hindered the opening of the upper tobacco leaves. Spraying a certain concentration of clopifenuron and brassinolide can improve the maturity and appearance quality of tobacco leaves. The sensory quality of tobacco leaves was significantly improved by spraying forchlorfenuron and brassinolide, among which T2 and T6 treatments had the highest score of 61.80 points, 3.80 points higher than the control. Spraying a certain concentration of forchlorfenuron and brassinolide could reduce the nicotine content, increase the sugar-base ratio, increase the potassium content, coordinate the conventional chemical components, and improve the taste of tobacco leaves. The production and output value of the upper part and the proportion of high-grade tobacco can be significantly increased by spraying forchlorfenuron, among which the production and output value of T4 and T6 treatments are the highest. In conclusion, forchlorfenuron spraying was superior to brassinolide in all aspects of tobacco leaf improvement, and T6 treatment with 75 mg·L^-1 forchlorfenuron spraying had the best effect.

Key words: exogenous substances, plant growth regulator, upper tobacco leaf, yield and quality