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ASSESSMENT OF SALT TOLERANCE OF SOME NEWLY DEVELOPED AND CANDIDATE WHEAT (TRITICUM AESTIVUM L.) CULTIVARS USING GAS EXCHANGE AND CHLOROPHYLL FLUORESCENCE ATTRIBUTES

HINA KANWAL¹, MUHAMMAD ASHRAF^1,2*, MUHAMMAD SHAHBAZ¹

Abstract: The present study was aimed to assess salt tolerance of some newly developed and candidate cultivars of wheat using gas exchange and chlorophyll fluorescence parameters. Ten wheat cultivars including five newly developed (S-24, Saher-2006, Fsd-2008, Lasani and Inqlab-91) and five candidate (P.B-18, M.P-65, S.H-20, AARI-10 and G.A-20) were grown in sand culture. Salt stress (150 mM NaCl in Hoagland’s nutrient solution) was applied at the seedling stage. A significant reduction in plant biomass production was recorded in all wheat cultivars. Cultivars S-24, Saher-2006 and Fsd-2008 showed less reduction in biomass production as compared with the other cultivars. Different gas exchange attributes such as leaf net photosynthetic rate (A), transpiration rate (E), and stomatal conductance (g_s) were also adversely affected due to salt stress and were positively associated with the plant biomass production of the genotypes under saline stress. More negative effects in relation to these gas exchange attributes were recorded in cvs. Lasani, G.A-20 and ARRI-10 than those in the other cultivars. Leaf maximum chlorophyll fluorescence (Fm), maximum fluorescence at steady state (Fms), and photochemical fluorescence quenching (Qp) increased while maximum quantum yield (Fv/Fm), quantum yield of electron transport (Qp), electron transport rate (ETR) and non-photochemical quenching (Qn) decreased due to imposition of salt stress. The adverse effects of salt stress on these chlorophyll fluorescence attributes were minimum in cultivars S-24, Saher-2006 and Fsd-2008. A significant positive correlation was recorded between biomass production, different gas exchange attributes and chlorophyll fluorescence parameters. Overall, cvs. S-24, Saher-2006 and Fsd-2008 were ranked as salt tolerant on the basis of their performance in biomass production, gas exchange attributes and chlorophyll fluorescence parameters.

¹Department of Botany, University of Agriculture, Faisalabad, 38040, Pakistan
²Department of Botany and Microbiology, King Saud University, Riyadh, Saudi Arabia
[1]Corresponding author: E-mail: ashrafbot@yahoo.com; Fax #: +92-41-9200764 Ph #: +92-41-9200312,