The effect of sowing date and intra-row space on leaf area index, dry matter accumulation and physiological characteristics of roselle (Hibiscus sabdariffa L.) as medicinal plant

Roselle )Hibiscus sabdariffa  L.) is a new medicinal plants can be used as a suitable plant in cropping pattern. Recently, due to different uses has been considered by farmers. In order to evaluate the effects of sowing date and intra-row on leaf area index, dry matter accumulation and physiological characteristics of roselle (Hibiscus sabdariffa L (.the field experiment was conducted split plot in a randomized complete block design with three replications in agricultural research field of Jiroft university during 2013 and 2014 growing season. Main plots were sowing date at five levels of 11th and 30th March, 14th April, 5th and 22th May and intra-rows were spaced of 100, 75 and 50 cm as sub plot. Based on two years data combined analysis, the results indicated that delayed sowing date reduced leaf area index, dry matter accumulation, sepal yield, seed yield and biomass yield. The highest sepal yield and seed yield was obtained at 11th March, with 990 and 1338 kg/ha, respectively. The lowest sepal yield and seed yield was obtained at 22th May, with 594 and 766 kg/ha respectively. Sepals yield increased at 50 cm intra-row space to 75 and 100 cm intra-row space 24% and 61% respectively, also seed yield increased 9.5% and 20% respectively. Sowing date had significant effect on sepal antioxidant, acidity, vitamin C, seed protein and seed oil. The percentage highest of antioxidant activity sepals (90.17%) belonged to the 5th May. Intra-rows space had not a significant effect on physiological characteristics. Roselle sowing date date in the first half of March to mid of May with intra-row space of 50 cm, seems to be appropriate by the good climatic conditions of Jiroft region.