Document Type : Research Paper
Authors
1
Department of Genetics and Herbal Medicine, Faculty of Agriculture and Natural Resources, Imam Khomeini international university, Qazvin, Iran
2
Department of Genetics and Herbal Medicine, Faculty of Agriculture and Natural Resources, Imam Khomeini international university, Qazvin, Iran.
3
Seed and plant Improvement Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran.
Abstract
Introduction: Water scarcity is one of the major limiting factors to agricultural production across the globe and it is predicted that drought spells will occur more frequently in the future due to the long-term effects of global warming (Rivero et al., 2007). This has led to a decrease in canopy size, loss in photosynthesis and consequently reduced crop yields. Alfalfa, being perennial and multi cut, as well as having an efficient root system, can tolerate water limited conditions by dormancy and is able to restart its biological activities after irrigating (Mc Williams, 2002). The mechanisms of response to water stress are complex and include activation of growth regulators in molecular and physiological levels. In addition, the yield potential and stability of some Iranian alfalfa ecotypes in different locations have been investigated previously (Mofidian & Moghaddam, 2013).
Material and Methods: The experiment was carried out with 10 warm and cold region alfalfa ecotypes in two distinct environments at Seed and Plant Improvement Institute (SPII), Karaj, Iran, over the years 2016-2018. The environments included full irrigation and no watering for 20 days from 22th of June. To conduct a preliminary evaluation of the ecotypes response to water stress, stress susceptibility index (SSI) based on fresh forage yield was calculated. The most important physiological traits measured in this study were as follows: relative water content (RWC), chlorophyll content index (CCI), canopy temperature depression (CTD), and stomatal resistance (SR), Chlorophyll a and b contents and carotenoids. Combined analysis of variance and mean comparisons were done by SPSS Ver.22 and Excel 2016.
Results and Discussion: The effect of no watering stress on all of the physiological traits was significant (P
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