جستجوی مقالات مرتبط با کلیدواژه « deficit irrigation » در نشریات گروه « بیوتکنولوژی و ژنتیک گیاهی »

Deficit irrigation is one of the new ways to reduce the effects of drought stress because crops can be supplied with available water in a controlled manner throughout the growing season. In order to investigate the effects of deficit irrigation on two local variety of ajwain, a factorial experiment was conducted based on a randomized complete block design with three replications in 2017 in the Research Farm of University of Birjand, Iran. The factors included three levels of soil moisture deficit (SMD: 50, 75 and 100 percent of field capacity), and two landraces of ajwain (Birjand and Sistan). Vegetative traits including plant height, leaf area and weight, yield components and quantitative and qualitative yield were measured. Resutls revealed that a reduction in the irrigation level, from 100 to 50% of field capacity, caused the grain yield, essential oil yield, biological yield, seed weight and number of umbels per plant to be reduced significantly. Sistan landrace had a higher chlorophyll a and b and carotenoid contents than Birjand, which may reflect an increase in the special leaf area (increased thickness) of Sistan landrace. Two landraces showed a different response to reduced irrigation. The growth characteristics and quantitative and qualitative yields of Sistan landrace were less affected by low irrigation levels, compared to Birjand landrace. In general, it can be said that the local variety of Sistan has a better compatability with deficit irrigation; however there was no significant difference between grain yield and essential oil yield of these two landraces.

Deficit irrigation is a technique for optimizing crop production under drought stress conditions. The superabsorbent hydrogel is a hydrophilic polymer being able to absorb and retain a large amount of water. This study was conducted to evaluate the effect of different rates of Super AB A 200 superabsorbent hydrogel on yield and yield components of corn cv SC704 under drought stress. The experiment carried out in split plot based on a randomized block design in Hamidieh region, Khuzestan province, Iran. In this study, three different depths of irrigation were considered as the main plot including 100, 75 and 50% of water requirement of plants respectively and different levels of superabsorbent were used as sub-plot including 0 (control), 15, 30 and 45 g/m2, respectively. Increasing drought stress led to significant loss of yield, yield components and decrement in water use efficiency of corn The effect of drought stress was determined by decreasing leaf surface area index, disruption of nutrients uptake and transfer, which ultimately led to a decrease in the supply of nutrients, yield and yield components. Finally, it was concluded that superabsorbent hydrogel is effective in retaining water and nutrients and releasing them under drought stress conditions and significantly prevents the decline of yield and yield components. It is recommended to use 75% of plant water requirement and 45 g/m2 superabsorbent for corn cultivation under Khuzestan province climate conditions.

In an attempt to investigate the effects of the levels of deficit irrigation and wheat stubble management on the agronomical and morpho-physiological traits of mung bean (Vigna radiate L.), an experiment was carried out in split-plot following a randomized complete block design with three replications during 2009. The main factor comprised deficit irrigation at three levels: the interrupted irrigation at the onset of podding (I1), the interrupted irrigation at the onset of flowering (I2), and the common irrigation (I3). The subplots included wheat stubble management at three levels: planting in stubble by zero tillage (M1), planting in burned stubble by zero tillage (M2), and planting by traditional tillage. The results indicated that the aforementioned treatments had significant effect on grain yield, plant height, the number of secondary branches, dry matter, and harvest index. Grain yield, the number of secondary branches, stem diameter, plant height, dry matter, and harvest index were higher in common irrigation in comparison to the other irrigation levels. Grain yield, the number of secondary branches, dry matter, and harvest index were also higher in traditional tillage compared to M1 and M2 treatments. The Mean comparison of the interaction effect of irrigation and stubble managements revealed that the highest and the lowest grain yield were produced by common irrigation with traditional tillage and the interrupted irrigation at the onset of flowering with planting in stubble, respectively.

The experiment was conducted during 2004-2006 growing seasons at the Agricultural Research Station, Islamic Azad University, Naragh Branch, to evaluate the effects of water deficit on growth indices of three bread wheat (Triticum aestivum L.) cultivars. A split plot experiment based on a randomized complete block design with four replications was used in both years. Irrigation treatments (irrigation after 70 (I1), 90 (I2) and 110 (I3) mm of cumulative evaporation from class A evaporation pan) were considered as the main plot and wheat cultivars (Mahdavy, Sepahan and Roshan-back cross) as subplots. Irrigation after 70 and 90 mm cumulative evaporations did not modify growth indices, significantly. Delay in irrigation from 90 to 110 mm cumulative pan evaporation significantly reduced the growth indices. Pattren of changes in leaf area index (LAI), total dry matter (TDM), net assimilation rate (NAR), and crop growth rate (CGR) were similar in both 70 and 90 mm treatments. At samplings, delay in irrigation from 90 to 110 mm cumulative evaporation lowered the incraese of all growth indices. Pattern of changes in CGR was more similar to LAI but dissimilar to NAR. The results indicated that 22% water could be saved when wheat plants were irrigated after 90 mm of cumulative pan evaporation. However, a decrease of growth indices and grain yield under this water condition was not important.