Growth and Flowering Performance of Marigold (<i>Tagetes erecta</i> L.) under Different Nitrogen Fertilization Regimes<b></b>

A pot study was conducted in the winter season 2022-2023 at the Nursery of the Department of Horticulture, Sindh Agriculture University, Tandojam, to evaluate the response of two varieties of marigold namely Deep Orange and Marvel Yellow to different nitrogen application rates. The experiment was laid out in a Completely Randomized Design (CRD) with factorial arrangement of treatments and replicated three times with five levels of nitrogen (0, 30, 60, 90, and 120 kg ha-1) and two varieties of marigold. The following data were obtained: plant height, number of branches per plant, days to flowering, individual flower weight, total flower weight per plant, flower diameter and flowering duration. The results revealed that nitrogen application had a significant effect on all the growth and flowering traits of marigold. The vegetative growth, flower development and yield of both varieties were generally enhanced with increasing nitrogen levels, with varying magnitude of response. Marvel yellow consistently outperformed Deep Orange at all nitrogen rates, especially at the highest rate (120 kg ha-1) where it exhibited the tallest plants (20.03 cm), the most branches (34.33), the heaviest single flower (9.27 g) and the greatest flower yield per plant (22.64 g). The most flower diameter (40 mm), the first flowering initiation (16 days) and the most flowering period (39.66 days) were also achieved under the highest nitrogen treatment. Nitrogen fertilization stimulated growth of both cultivars but differences in growth were less marked at low nitrogen rates. The results show that the use of 120 kg ha-1 nitrogen application can significantly increase the growth, flowering ability and flower yield of marigold especially for cultivar Marvel Yellow. The results obtained would be helpful for choosing appropriate cultivars and proper nitrogen management to improve marigold production under similar agro-climatic conditions.