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To study the effect of different irrigation regimes and plant densities on yield, yield components and morphological traits of artichoke (Cynara scolymus L.), an experiment was conducted as split plot in a randomized complete block design with three replications at Sarabelle Agricultural Research Station in Ilam province during 2014-2015. The treatments comprised four irrigation regime, 25 %, 50 %, 75 % and 100 % (control) of the water requirement of the plant in the main plots and four plant densities, 10000, 20000, 30000 and 40000 bushes in hectare, in sub plots. The results showed that the highest total height (254 cm), height to the beginning of lateral branches (170 cm), mean canopy diameter (136 cm), number of leaves (59 per plant) and 1000-seed weight (39 g) At a density of 40,000 plants per hectare under 100% water requirement the plant was obtained. The highest number of buds (13 pcs. Per plant) and lateral shoots (13 pcs. Per plant) were observed at 10000 plant ha-1 under 100% water requirement. The highest fresh and dry weight of shoot, seed yield and seed oil yield were obtained with average of 64943, 25416, 3339 and 694 kg / ha with 40,000 plants / ha under 100% water requirement, respectively. According to the results of this study, the highest yield was obtained at 40,000 plants / ha under 100% water requirement of the plant, but even in severe dehydration conditions, it had high ability to produce forage, seed, bud and shoot. In high drought stress conditions (25% water requirement) and density of 40,000 plants / ha, more than 14 ton dry shoots, 2.5 ton grain and 0.5 ton oil seed per hectare..The results of qualitative study of forage of plant organs by leaves, stems, buds and seeds showed that out of a total of about 24 tons of dry matter yield per hectare in the control treatment, 39, 34, 15 and 12% belong to buds, stems, and leaves, respectively. And it was the seed. The low amount of leaf forage compared to bud and stem organs was due to plant harvest in the second year. Increasing drought stress decreases forage yield (dry matter, crude protein, digestible dry matter and water-soluble carbohydrates) but increases the quality and nutritional value of forage (increasing crude protein, digestible dry matter and water-soluble carbohydrates), despite the relative increase in ADF and NDF was in artichokes. Increasing the density also led to increased yield, percentage of water-soluble carbohydrates, percentage of total ash, percentage of insoluble fibers in acidic detergent and percentage of insoluble fiber in neutral detergent and decreased percentage of crude protein, percentage of digestible dry matter and percentage of crude fiber. In general, due to the fact that the functions of crude protein, digestible dry matter and water-soluble carbohydrates are completely affected by dry matter yield, and the most important trait for farmers is the dry weight of the crop, so the control treatment (without water stress) and density 40,000 plants per hectare have the highest dry matter yield (leaves, stems, buds and seeds (4100, 9637, 11680, 3339 and a total of 28756 kg / ha, respectively) and are recommended for forage production.The results showed that the active ingredients of the two leaves and buds of the plant , increasing drought stress caused 78 and 11% reduction in naringin amount compared to control treatment of bud and leaf extract, respectively. The maximum amount of caffeic acid (0.74 mg/g dry matter) was observed in leaf extract and interaction effect of full irrigation and 10 thousand bushes in hectare. Drought improved caffeic and chlorogenic acid biosynthesis of bud, but in interaction effect with density, only chlorogenic acid had the highest amount in sever water stress and 10 thousand bushes in hectare.Among consumed organs extract, caffeic acid and naringin had the highest amount in leaf extract, and chlorogenic acid in bud extract.
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