كليدواژه :
تنش خشكي , دانه روغني , فاصله بوته روي رديف , مرحله نموي
چكيده فارسي :
به منظور بررسي اثر كم آبياري و تراكم بوته بر رشد و عملكرد دانه و برخي خصوصيات مورفولوژيكي گلرنگ پاييزه (Carthamus tinctorius L.) (رقم محلي اصفهان)، آزمايشي به صورت كرت هاي خرد شده در قالب طرح پايه بلوك هاي كامل تصادفي و در چهار تكرار در مزرعه دانشكده كشاورزي دانشگاه بيرجند در سال 93- 1392 اجرا شد. تيمارها شامل سه سطح آبياري (آبياري كامل، آبياري تا گلدهي، آبياري تا تكمه دهي) در كرت هاي اصلي و چهار سطح تراكم بوته (20، 30 ، 40 و 50 بوته در مترمربع) در كرت هاي فرعي قرار گرفتند. نتايج نشان داد، تنها در تيمار آبياري تا مرحله تكمه دهي كاهش ارتفاع بوته، فاصله اولين انشعاب از سطح خاك و تعداد شاخه هاي اوليه و ثانويه مشاهده شد. با افزايش تراكم، ارتفاع بوته و فاصله محل اولين انشعاب شاخه ها از سطح خاك افزايش يافت، اما از تعداد روز تا رسيدگي و تعداد شاخه اوليه و ثانويه كاسته شد. به علاوه بيشترين عملكرد دانه (3607 كيلوگرم در هكتار) در تيمار آبياري كامل با تراكم 40 بوته در مترمربع به دست آمد و در تمامي تراكم ها، بيشترين كاهش در عملكرد دانه در تيمار آبياري تا مرحله تكمه دهي مشاهده شد. به نظر مي رسد اين مرحله رشدي حساس ترين مرحله به كمبود آب باشد و تحت اين شرايط، با انجام آبياري در اين مرحله مي توان عمكرد دانه را به طور قابل توجهي افزايش داد. به علاوه با توجه به نتايج اين آزمايش، به منظور دستيابي به حداكثر عملكرد گلرنگ در منطقه بيرجند آبياري كامل و تراكم 40 بوته در مترمربع پيشنهاد مي شود.
چكيده لاتين :
Introduction
Vegetable oils such as safflower oil, due to high amounts of unsaturated fatty acids, play an important role in the fat balance of human diet and can reduce blood cholesterol level. Drought as the most important factor controlling the performance of the products, on a variety of factors that affect plant growth and yield (Ghamarnia and Sepehri, 2010). Although safflower is a drought resistant plant, but drought has significant effects on its duration of phenological stages, thus cause a significant reduction in yield, yield components, growth and some morphological traits such as plant height and distance to the first bifurcation branches from soil surface (Khoshnam et al. 2012). When the distance between plants in the row is low, vacancies are not green. Low density, especially in row plant spacing is not desirable. This experiment aims at identifying the critical stages of water and specifies the appropriate number of plants in conditions of stress and lack of tension in the area as well.
Material and Methods
In order to evaluate the effect of deficit irrigation and density on growth, seed yield and some morphological traits of a local variety of autumn safflower, an experiment was conducted with a spilt plot arrangement based on randomized complete block design with four replications at Research farm of Faculty of Agriculture, Birjand University in 2013-2014. Irrigation levels (complete irrigation, irrigation until flowering and irrigation until heading-bud stage) and plant density (20, 30, 40 and 50 plant per m2) allocated randomly in main plots and subplots, respectively. Phonological aspects (number of days to emergence, stemming, heading bud, 50% flowering and physiological maturity) were recorded. The terms consisted of plant height, distance to the first bifurcation branches from soil surface and number of primary and secondary branches and seed yield. SAS ver. 9.1 statistical software was performed to measure the results of the analysis of variance (ANOVA) and means were compared with LSD test in 5% probability level.
Results and Discussion
Results showed a significant reduction in plant growth period, plant height, distance to the first bifurcation branches from soil surface and number of primary and secondary branches in the irrigation until heading-bud treatment. The yield loss in this treatment was caused by early flowering and decrease in flowering period, seed filling period, maturity stage and yield components. It seems that the heading-bud stage is the most critical stage of the crop growing under water deficit conditions. Since all of the measured parameters had a positive correlation with seed yield, so a reduction of seed yield under the "irrigation until heading-bud treatment" is obvious. By increasing the plant density, plant height and distance to the first bifurcation branches from soil surface was increased but number of days until maturity and number of primary and secondary branches was reduced. In addition, the highest seed yield was obtained from full irrigation treatment with density of 40 plants per m2. In all plant densities, lowest seed yield was observed in the "irrigation until heading-bud" treatment. As it seems that this growth stage is the most susceptible stage of the crop to limited water, optimum irrigation in this stage may case a significant increase in seed yield.
Conclusion
According to the results of this experiment in order to achieve the maximum yield of safflower in Birjand region, full irrigation and density of 40 plants.m-2 is suggested. Supplementary irrigation during heading-bud stage is necessary to prevent a sharp drop in seed yield. The density of 40 plants.m-2 of safflower can cover the canopy faster and due to a reduction in soil evaporation, it can postpone the drought stress to the end of the growing season. This density, also with increasing the growing season, increasing the plant height and decreasing the number of low or non-fertile branches, results in better plant growth and thus helps to produce more seeds.
