Tagetes is a genus of annual, perennial or herbaceous plant in the family Asteraceae. Most of the species have pinnate green leaves. Blooms are naturally occurring in golden, orangeyellow, and white colour, often with maroon highlights. Floral heads are 4 to 6 cm in diameter, generally with both ray florets and disc florets. The present study was conducted at the post graduate research laboratory at Department of Horticulture, Faculty of Agriculture, Annamalai University to find out the “Effect of plant growth regulators on flowering and yield of African marigold (Tagetes erecta Linn)”. The experiment was laid out in Randomized Block Design with three replications. There were ten treatments, viz., GA3 100 ppm, GA3 200 ppm and GA3 300 ppm, NAA 100 ppm, NAA 200 ppm, NAA 300 ppm, Ethrel 50 ppm, Ethrel 100 ppm, and Ethrel 150 ppm and control. Among the growth regulators tried, GA3 200 ppm as foliar application on 30 and 60 days after transplanting registered the highest values for plant characters like plant height (47.1 cm), number of branches ( 35.1), days taken to first flower bud appearance (39.3 days), days taken to flower opening (37.6 days), longevity of flower (11.17 days), stalk length (12.1 cm), diameter of flower (7.8 cm), number of flowers per plant (40.3), weight of the single flower (9.1 g), yield of flowers per plant (337 g) and flower yield per plot (11.1 kg). From the present study, it is recommended that spraying of GA3 200 ppm on 30 and 60 days after transplanting improved yield and quality of African marigold flowers.
