Gadallah, A M. and M.A. Shama( 2006). Variation in Salt Tolerance of Wheat Genotypes ( Triticuium aestevium L.) during Germination and Maturity Stage.Alex, J, Res. (51) 1-11, Special Issue (2006)
Abstract: Salinity of irrigation water adversely affects plant growth, so the needs arise to develop salt tolerance plants for increasing the productivity of saline soils. Sixteen genotypes were investigated for tolerance during germination and at maturity stage. The results revealed that salinity of irrigation water had a prevailing effect on soil salinity. Soil salinity was increased proportionally by 1.2 dS/m for each increasing unit of applied water. During germination, adding saline water of 6000 mg/l significantly ( p ≤ 0.05) delayed emergence and the final germination percentage was markedly reduced. The germination percentage of different genotypes was also variable among different salinities. This would imply a significant interaction between salinity effect and plant vitality to germinate. This would permit for the inherent salt tolerance property in the different genotypes. Emergences of G4 then G3 were the most salt tolerance, while G15 and G16 were the most sensitive to salinity. At maturity, increasing salinity of irrigation water up to 12000 mg/l decreased significantly ( p ≤ 0.05) grain and biological yields, 1000-kernals weight, spike number/pot, number of kernels /spike, and plant height. Evaluation of salt tolerance among genotypes was performed by a response function equation related between soil salinity (ECe) and grain or biological yields. Electrical conductivity of the saturation extract (C50) associated with 50% reduction in yield was identified. The estimated values of C50 for grain and biological yield (over all genotypes) were 21.35 and 19.30 dS/m, respectively; indicating that biological yield for wheat was more sensitive to salinity than grain yield. G13 had the highest relative yield at the highest salinity level than the other genotypes on the basis of grain and biological yield. This genotype had comparatively low yield under both non-saline and saline conditions, and had the lowest reduction (46%) in grain yield with increasing salinity to 12000 mg/l. But, G3 had the lowest relative yield entry among the other genotypes, and the yield reduction at the highest salinity level was the greatest (71%). The response of number of spikes/pot, number of kernels/spike, and 1000-kernels weight to salinity of irrigation water were varied depending on genotypes and level of salinity. At the highest salinity level, G2 gave the highest number of kernels/spike and 1000-kernels weight while it's number of spikes/pot was the lowest. G15 holds the highest number of spikes/pot and possessed the lowest 1000-kernels weight. Once more, based on C50, all tested genotypes exhibited limited variations in their salt tolerance and were classified as salt tolerance and placed in the same category in spite of G5, G7, and G9 relatively more salt sensitive compared with the other genotypes. Another strategy was applied for selection for salt tolerance on the basis of vigor growth in saline and non-saline environment. On this basis, G2 and G11 could be described as acquiring both properties of high production and salt tolerance. In general, the results of this study indicated that salt tolerance during germination or early seedlings stage was lower than the salt tolerance during later growth stage and behave a different trend.
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