Effects of Sowing Time on Yield of Black Seed (Nigella sativa L.) Ecotypes under Mashhad Conditions

Growth and yield of medicinal plants affected by planting date as an important management factor. In order to study the effects of planting dates on yield and yield components of some black seed (Nigella sativa L.) ecotypes, a field experiment was arranged in a randomized complete block design as a split-plot with three replications at the Agricultural Research Station of Ferdowsi University of Mashhad during growing season 2009-2010. Four planting dates (24 Feb., 16 Mar., 4 Apr. and 25 Apr.) and four black seed ecotypes (Birjand, Gonabad, Neyshabour and Sabzevar) were allocated to the main and sub plots, respectively. Results showed that there were significant differences between planting dates for number of follicles per plant, number of seeds per follicles and 1000-seed weight, seed yield, biological yield and harvest index. Maximum numbers of follicles per plant, number of seed per follicles, biological yield and seed yield were observed in first planting date, maximum 1000-seed weight was observed in fourth planting dates and maximum harvest index were recorded in the third planting date. Yield components, seed yield, biological yield and harvest index also were affected by ecotypes and interaction effects of planting dates and black cumin ecotypes. The highest and the lowest of all traits, expect 1000-seed weight were achieved in Gonabad and Neyshabour ecotypes, respectively. The maximum and minimum 1000-seed weights were obtained in Neyshabour and Gonabad ecotypes, respectively. Planting in 24 Feb., 16 Mar. and 4 Apr. have had high seed yield and there was a reduction on seed yield due to delay planting to 25 Apr. Also, Birjand ecotype in the last planting date had the highest seed yield. According to the seed yield, Gonabad and birjand ecotypes were better than from two other ecotypes in range of planting dates