Effect of nitrogen doses on growth and yield of marigold (Tagetes erecta L.) in subtropical climate of Nepal

Marigold (Tagetes erecta L.) is a potential commercial flower with an increasing demand in Nepal every year. A field experiment was carried out to study the effect of different doses of nitrogen on growth and flower yield of marigold under container gardening at Bharatpur-11, Bhojad, Chitwan, Nepal during autumn 2018. Five treatments; T1-Control (0:90:75) kg NPK/ha; T2-(45:90:75) kg NPK/ha; T3-(90:90:75) kg NPK/ha; T4-(135:90:75) kg NPK/ha; and T5-(180:90:75) kg NPK/ha were evaluated in Randomized Block Design with four replications. Results showed that plant height, plant spread, and number of branches were statistically significant. Marigold plant applied with 180 kg/ha nitrogen gave the maximum height (49.47 cm), spread (36.40 cm), and number of branches (24.75/plant) in 45 DAT (days after transplanting) while the control plot showed the least. Similarly, nitrogen @ 180 kg/ha was found to be effective for early flowering initiation (32.50 DAT) and 50 percent for flowering (41.25 DAT) compared to control (39 and 48.75 DAT, respectively) and this also resulted in maximum number of flower(34.73/plant), maximum flower diameter (7.03cm) and higher yield (22.29 t/ha). Thus, the overall results suggest that the application of 180 kg N / ha in marigold was the most promising in terms of higher flower production.