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Pak. J. Bot., 44(5): 1533-1541, 2012.

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DETECTING DIFFERENCES IN WHEAT FOR SALT TOLERANCE THROUGH MULTI PARAMETERS EVALUATION-II: PHYSIOLOGICAL PARAMETERS

MOHAMMAD AKRAM¹, SHAFQAT FAROOQ², MUHAMMAD ASHRAF³, RUBINA ARSHAD¹, MOHAMMAD AFZAAL¹ AND FAROOQ-AZAM⁴

Abstract: A pot experiment was conducted in a randomized complete block design using 3 wheat genotypes comprising salt sensitive cultivar Inqlab (V1), a known salt tolerant line N-1073 (V2), a newly developed wheat genotype N-9760 (V3) and 4 salinity levels of 1.5 (control), 5, 10, and 15 dS m^-1 developed in irrigation water. The objectives were to examine i) variation in accumulation of different ions and different attributes of chlorophyll fluorescence on fully developed flag leaf and ii) possible relationship of quantum yield of chlorophyll fluorescence (F_v/F_m) with various ions and grain yield at maturity stage. Concentrations of Ca²⁺ in different genotypes differed significantly under control and various salinity levels in both root and shoot especially under 15 dS m^-1 ,Cl^- concentrations in roots and Na⁺ in shoots and roots increased while K⁺ reduced significantly in both shoots and roots under increasing salinity levels. Line N-1073 restricted the movement of Cl^- from root to shoot but not of Na⁺ under 15 dS m^-1 .Salt stress significantly reduced K⁺/Na⁺ ratio in the shoot and root with a maximum reduction observed in N-1073 (V2) under EC 15 dS m^-1. Ca²⁺/Na⁺ ratio also reduced significantly under salt stress especially in Inqlab (V1). All the four chlorophyll fluorescence parameters did not show any effect of salinity on N-1073 (V2), however, F₀ and F_v in V3 and V1 and F_v/F_m in V3 were significantly affected. In V2, the value of F_v/F_m was 0.82 at EC 15 dS m^-1 but for V3, it was only was 0.28. The relationship of F_v/F_m with various ion concentrations and grain yield was different for all the three genotypes. Categorization of germplasm on the basis of increasing tolerance was of the order of V1, V2 and V3. Possible underlying reasons have been discussed in detail.

¹Nuclear Institute for Agriculture & Biology (NIAB), P.O. Box 128, Jhang road Faisalabad, Pakistan

²Director (Technical), PAEC HQ, Opposite K Block Secretariat, Islamabad, Pakistan

³Department of Botany, University of Agriculture, Faisalabad, Pakistan

⁴Chief Scientist, Pakistan Institute of Engineering and Applied Sciences (PIEAS), Nilore, Islamabad, Pakistan

^*Corresponding author’s email: shafqat_niab@hotmail.com