Plant population is crucial to yield enhancement of white cumin (Trachyspermum ammi) in northwestern Ethiopia

A field experiment was conducted during August 2017 and January 2018 at Dembia district of Ethiopia, to determine the optimum plant population of white cumin [Trachyspermum ammi (L.) Sprague ex Turrill] by adjusting inter- and intra-row spacings. The experiment consisted of a complete randomized block design with 4 inter-row spacings (30, 40, 50 and 60 cm) and 3 intra-row spacings (10, 15 and 20 cm), replicated 3 times. The maximum mean days to flowering (92 days) were recorded in plant spacing of 50 cm × 20 cm. The highest numbers of primary and secondary branches were obtained in 60 cm × 20 cm spacing. The maximum numbers of umbels and umbellets were recorded in 40 cm × 20 cm spacing. The interaction effects of spacings on plant height, biological yield, seed yield, and harvest index were significant, while those on days to flowering and maturity, number of primary and secondary branches, number of umbels and umbellets, and 1,000-seed weight were non-significant. It is concluded that white cumin should be planted at the spacing of 40 cm × 10 cm in Dembia district and similar other agroecological areas of Ethiopia to achieve the maximum yield.