engleski

Effects of Topping Height, Maturity and Cultivar on the Yield and Chemical Characteristics of Flue-cured Tobacco.

Effects of topping height, maturity and cultivar on the yield and chemical characteristics of fl ue-cured tobacco were studied in 2004-2005 and 2007. Investigations were carried out in the main tobacco growing region of Croatia according to the split-split plot method. Th e trial involved the following treatments: (1) topping height (17 and 20 harvesting leaves), (2) leaf maturity at harvesting (unripe, ripe and overripe) and (3) cultivar (HVT 1, VJ 1, DH 17). Effects of topping height were obtained in this study only in interaction with maturity and cultivar. Topping height in interaction with leaf maturity aff ected the yield and nicotine content in dry years, and in interaction with cultivar in the year with suffi cient precipitation the content of reducing sugars. Leaf maturity at harvesting aff ected the content of total nitrogen, proteins and reducing sugars in interaction with cultivar in 2007, marked by a forty-day water stress and retrovegetation from the second decade of August. Leaf maturity at harvesting in 2004 and 2005 had no impact on yields. Th e highest yield was achieved by harvesting ripe tobacco topped to 20 leaves in 2007. Delayed harvesting increased the nitrogen content. In 2004, total nitrogen in overripe tobacco was signifi cantly higher compared to ripe tobacco. Protein content increased until optimum maturity in 2005 and then decreased. In 2005, higher topping of cultivar VJ 1 resulted in a higher content of reducing sugars. Intensity of the decrease in the content of proteins and reducing sugars, as well as changes in total nitrogen caused by delayed harvesting in 2007 depended on cultivar characteristics. A weak positive correlation was established between yield and total nitrogen.

flue-cured tobacco; yield; nicotine; total nitrogen; proteins; reducing sugars

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