نشریه پژوهشهای زراعی ایران
سال هشتم شماره 5 (پیاپی 19، آذر و دی 1389)

In order to investigate the effect of fall and winter planting dates on phenological and morphological traits, yield and yield components of four cumin (Cuminum cyminum L.) landraces, an experiment was conducted at the Research Farm of Agricultural College of Ferdowsi University of Mashhad as a split plot based on randomized complete block design with three replications in 2005-06 growing season. Four planting dates (11th Nov., 11th Dec., 20th Feb. and 17th Mar.) were allocated to main plots and four landraces (Ghayen, Torbat-e-heidariyeh, Sabzevar and Khaf) were assigned to sub plots. The results indicated that the effects of planting date, landrace and interaction effect of these two factors on plant height, percent of plant survival after winter, yield components, seed yield, biological yield and harvest index were significant. With respect to plant height, there was no difference between fall (11th Nov. and 11th Dec.) and winter (20th Feb.) planting dates, while plant height in the fourth planting date (17th Mar.) decreased severely. The lowest percent of plant survival was observed in the fall sowing dates, while the third and fourth plantings had no plant mortality, for not exposing to cold conditions. The maximum percent of plant survival belonged to Ghayen and Khaf landraces with 85% and 84% respectively, and Torbat-e-heidariyeh had the lowest percent of plant survival with 59%. The greatest number of umbels per plant, number of seeds per umbel, 1000 seeds weight and seeds weight per plant were achieved in the first planting date. Despite priority of the first planting date in yield components over other planting dates, the greatest seed yield and biological yield observed in the third planting date (20th Feb.). With regard to seed yield and biological yield, Ghayen in the third planting and Torbat-e-heidariyeh in the first planting had the greatest and the lowest yields, respectively. Since the fall and winter planting dates led to improve plant growth particularly vegetative growth, plant height and some of yield components in contrast with spring sowing date, it can be concluded that with planting cold tolerant cumin genotypes due to decreasing the plant mortality in cold conditions, cumin yield will be improved.

In order to study the effect of different amounts of nitrogen and plant density on growth, yield, the percentage of essential oil in leaf and essential oil yield of peppermint (Mentha piperita L.), an experiment was conducted in 2008 at the Experimental Field of the Agricultural Faculty of Bu-Ali Sina University. The experiment was split plot based on randomized complete block design with three replications over two cuts. The main plots included the amounts of 100, 150 and 200 kg nitrogen/ha in which half of fertilizer were used for the first cut and another half for the second. The sub-plots were consisted of plant densities as 8, 12 and 16 plants/m2. Morphophysiological characteristics including plant height, node and leaf number per plant, leaf area index, fresh and dry yield, essential oil percentage in leaf and essential oil yield over two cuts, and also the growth of dry matter, leaf area index and crop growth rate in the first cut were measured. The results showed that, nitrogen treatment significantly affected the properties measured, so that, their highest rates were obtained with the application of 100 and 200 kg nitrogen/ha from the first and the second cut, respectively. In addition, total dry matter, leaf area index and crop growth rate increased with increasing the amounts of nitrogen. Plant density also affected the plant height; node number, leaf number and leaf area index, essential oil percentage in leaf and essential oil yield in the first cut significantly, and in the second cut, plant density effect on leaf number and leaf area index was significant as well.