Growth and Flowering Response of Two Species of Marigold (Tagetes spp.) to Water Stress

Marigold (Tagetes spp) is among the high value potted flowers with an extended shelf life. It is commercially exploited for cut flowers. A pot experiment was conducted between February and May 2013 in the greenhouse of the College of Plant Science and Crop Production, Federal University of Agriculture, Abeokuta, Nigeria to determine the growth and flowering response of two species of marigold: Tagetes erecta L. (African marigold) and Tagetes patula L. (French marigold) to water stress levels (0.5, 0.75 and 1 litre per plant per week). The experiment was laid out in a 2 x 3 factorial fitted in a completely randomized design with seven replicates. Data were collected on shoot height, number of leaves, canopy diameter, number of branches, number of flowers, and flower yield. Data collected were subjected to analysis of the variance (ANOVA) using GENSTAT 12th edition while significant mean separation was done using least significance difference (LSD) at 5% level of probability (Wahua, 1999). The results showed that French marigold was shorter, even though it elicited more number leaves, wider plant spread, more branches, higher number of flowers, and flower yield than African marigold. Irrigation at 0.75 and 1 L/week rates produced taller plants, more leaves, branches, flowers, and flower yield than plants that received 0.5 L/week. Both varieties irrigated at 0.75 and 1 L/week produced taller plant, more leaves, branches, flowers and flower yield than 0.5 L/week. However, there was no significant difference between Marigold species that received water at 0.75 and 1 L/week. In conclusion, irrigating either specie of marigold at 0.75 L per 7 kg of soil enhanced their growth and flower production.