Abstract

Tesfu Mengistu and Charles Yamoah

An experiment was conducted in 2006 and 2007 cropping seasons to investigate the effect of sowing date and planting density on yield and quality of carrot seed. The crop was grown in factorial combination of four sowing dates (mid November, December, January and February) and four different planting densities (133 333, 200 000, 266 666, and 400 000 plants/ha) in randomized block design with three replications. The plant spacing corresponding to the aforementioned densities were 50 cm × 5 cm; 50 cm × 10 cm; 75 cm × 5 cm and 75 cm × 10 cm, respectively. Both yield and seed quality declined progressively as sowing was delayed from November to February. Increasing the planting density from 133 333 plants/ha to 400 000 plants/ha increased the overall seed yield of November and December plants. However, for January and February, seed yield was observed to decline with increased planting density, because of heavy rainfall and infestation of Alternaria leaf blight at flowering stage. Planting density had no significant effect on seed quality (p 0.05). Seed yield per plant significantly (r = 0.55*) correlated with number of branches per plant, plant height (r = 0.73**), umbel diameter(r = 0.780**), number of umbels per plant (r = 0.576**), number of umbellets per umbel (r = 0.783**) and with seed weight per umbel (r = 0.894**).