Effect of spacing, levels of nitrogen and topping on yield and quality of irrigated natu tobacco (Nicotiana tabacum) grown in Alfisols of Andhra Pradesh

A field experiment was conducted during 1998–2000 seasons to find out optimum plant population, nitrogen dose and topping level for the irrigated natu tobacco (Nicotiana tabacum L) variety ‘Kommugudem’. Top quality (melimi), second quality (gulla) and total leaf yields at closer spacing of 80 cm x 80 cm were significantly higher than 100 cm × 80 cm spacing. Application of 450 kg N/ha being at par with 400 kg N/ha recorded significantly higher melimi and total leaf yields as compared to 350 and 300 kg N/ha. Topping at 16 leaves recorded significantly higher top quality, second quality and total leaf yields than topping at 14 leaves. Chemical analysis of leaf indicated that wider spacing of 100 cm × 80 cm had higher nicotine and lower reducing sugars than closer spacing of 80 cm × 80 cm. The nicotine content of the leaf increased, while the reducing sugars and sugar; nicotine ratio decreased with increasing levels of nitrogen. Topping at 14 leaves showed higher nicotine and reducing sugars than topping at 16 leaves. Economics showed that irrigated natu tobacco can be grown profitably with 80 cm x 80 cm spacing fertilized with 400–450 kg N/ha and topped at 16 leaves.