Influence of Nitrogen and Phosphorus on Flowering in African Marigold (Tagetes erecta L.) Var. Cracker Jack

An investigation was conducted during the year 2000 to study the effect of nitrogen and phosphorus on flowering in African marigold. Results revealed that among the four levels of nitrogen tested, highest level of nitrogen (N3) led to minimum number of days for the first flower-bud to become visible (31.66 days), days to flower-break (38.55 days), days to full-flowering (50.66 days). Plants receiving N2 recorded significantly high number of flower heads per plant (28.42) and yield (11.11 t/ha). Among the three levels of phosphorus tested, days taken to appearance of the first flower-bud, flower-break and full-flowering were significantly earlier in a treatment with no phosphorus (P0). However, number of flower heads per plant was significantly higher in P2 (28.3). As for interaction effect, a combination of the highest level of nitrogen with no phosphorus (N3P0) recorded early flowering. Number of flower heads per plant was higher in N3P2 (31.83). Highest flower-yield (11.65 t/ha) was recorded in N3P2. Thus, it is concluded that nitrogen application advances flowering, while, phosphorus application delays flowering.