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Investigation Of Differences In Salt Tolerance Mechanisms In Contrasting Bread Wheat Genotypes

Saqib, Zulfiqar Ahmad (2010) Investigation Of Differences In Salt Tolerance Mechanisms In Contrasting Bread Wheat Genotypes. PhD thesis, University of Agriculture, Faisalabad .

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Abstract

The genotypic differences regarding Na+ accumulation and transport in plant along with physiological response to improve salt tolerance were studied in bread wheat genotypes.Four wheat genotypes; Kharchia-65, SARC-3, S-9476 and S-8189 were grown under salt stress (75 and 150 mM NaCl) in nutrient solution with five replications. Shoot dry weight, relative growth rate (RGR), chlorophyll index, leaf water relations, Na+ content and transport in plant were measured.The increase in NaCl stress decreased all growth parameters, however, variations were observed among genotypes. Kharchia-65, S-9476 and SARC-3 had better growth and water relations compared to salt sensitive genotypes S-8189. The low rate of Na+ transport and better ability to restrict Na+ in the root was main reason of genetic variation among different genotypes, especially, when growth characteristic did not vary significantly under salt stress. Na+ partition was also recorded in wheat genotypes as salt sensitive genotypes had higher Na+ accumulation in shoot while it was reverse in tolerant ones. The differences in root Na+ were not significant among all genotypes. In many crop plants, over-accumulation of Na+ in shoot is the main cause of yield reduction due to toxicity. In this study, wheat genotypes differed mainly because of low rates of Na+ uptake and transport from root to shoot. Therefore, in this study, it was concluded that wheat genotypes with contrasting leaf Na+ uptake rates and transport from root to shoot had resulted in differences in salinity tolerance. The wheat genotypes having ability to reduce Na+ accumulation in shoot by retaining it at root level had better salt tolerance. The genotypes with the highest Na+ uptake had lower chlorophyll, more electrolyte leakage, and a slightly lower RGR.

Item Type:Thesis (PhD)
Uncontrolled Keywords:Mechanisms, Genotypes, Ion, Partition, Salinity, Tolerance, Stress, Sodium, Wheat, Investigation, Bread, Contrasting
Subjects:Agriculture & Veterinary Sciences(a) > Agriculture(a1)
ID Code:7253
Deposited By:Mr. Javed Memon
Deposited On:21 Dec 2011 10:26
Last Modified:21 Dec 2011 10:26

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