Thesis (PH.D.) - Cairo University - Faculty Of Agriculture - Department Of Agronomy

The genetic material used in this investigation comprised seven genotypes [Giza 83 , Giza 45 , F1 , SF2 plants , TF2 plants of the hybrid Giza 83 x Giza 45 and check varities (Giza 90 and Dendera) ] of the Egyptian cotton (Gossypium barbadense L2n=52) Giza 45 variety exhibited the least values of boll weight , Noof open bolls / plant , lint percentage , proline content and seed cotton yield / plant compared to the other genotypes under the two experiments (pots and El - Maghara region) The results indicated that agronomic and physiological characteristics were more sensitive to salinity than the technological one'sBoth SDS - PAGE of soluble proteins and Randomly Amplified Polymorphic DNA (RAPD) analysis were employed to evaluate , the genetic diversity and genetic relationships among studied genotypesFive random 10 - mer primers were used to amplify DNASimilarity matrix was generated from the RAPD analysis ; its values ranged from 0058 to 0990The salt - sensitive parent (Giza 45) and the sensitive F2 bulk , exhibited two negative PCR - RAPD markers with molecular sizes of 2489 and 1875 bp using primer OP - Z15The tolerant parent (Giza 83) and the tolerant F2 bulk exhibited three positive molecular markers with molecular sizes of 317 , 1507 and 2137 bp with OP - Z07 and OP - Z15 primersGiza 90 and Dendera (the two check varieties) seemed to be salt - tolerant genotypes as they exhibited a positive molecular marker (1507 bp) with primer Z15In conclusion , the negative markers can be used as indicators to distinguish the salt - sensitive cotton lines in breeding programs

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