Document Type : Research Paper
Authors
1 scientific board of dryland agricultural
2 Dryland Agricultural Research Institute
3 Department of Agriculture, Payame Noor University (PNU), Iran
Abstract
Introduction: Changing the chickpea planting system from spring to autumn, due to the increase in the length of the growing period, proper productivity from the late winter and early spring rains, the coincidence of the flowering and podding period with suitable soil moisture, and finally avoiding the dryness at the end of the season, is result in increasing the yield in Mediterranean climates. Wild relatives are useful sources of genetic diversity and resistance genes to biotic and non-biotic stresses, and the wider the base of diversity, the more likely the breeder will be able to find the desired genetic combination.
Methodology: Photosynthetic efficiency and biochemical response of dryland chickpea genotypes were evaluated as factorial experiment based on a completely randomized design with two replications under cold stress in two genotypes ILWC109 and ILWC119 along with two genotypes i.e. Ana (resistant control) and ILC533 (sensitive control). In the controlled environment, three different temperature levels including 22°C (as control), 4°C and -4°C were considered to evaluate biochemical characteristics.
Research findings: The results of the field section showed that genotypes number 5 (ILWC109) and 23 (ILWC119) not only had the highest amount in terms of chlorophyll a content, but also in terms of ELI index and activity levels of CAT and PPO enzymes. They were better than other genotypes and cultivars and were recognized as cold resistant genotypes. In the controlled part, the results showed that the maximum fluorescence, the maximum photochemical efficiency of photosystem II, the efficiency of the water split complex in photosystem II and the photosynthetic efficiency significantly decreased in the studied genotypes under cold stress of -4°C. On the other hand, at -4°C, the amount of light current absorption increased in active reaction centers. The highest level of maximum fluorescence and photochemical efficiency of photosystem II and the lowest amount of light current absorption in the active reactive center were obtained in ILWC109 genotype. It seems that Anna genotypes and ILWC109 line have been able to increase the number of photosystem II active reaction centers under cold stress conditions of -4°C, and by absorbing light photons, electron transfer could take place with better efficiency. The improvement of the photochemical efficiency of photosystem II confirms this mechanism of action in genotypes tolerant to cold stress.
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