Thesis (M.Sc.) - Cairo University - Institute of African Research and Studies - Department of Natural Resources

Peanut is an important edible oilseed crop in the world. Salinity is one of the important abiotic stresses affecting peanut productivity. The present study aim to determine salt tolerant genotypes among the Egyptian and Nigerian investigated genotypes. Growth parameters were estimated. Na+, K+, Mg++, Ca++, as well as, proline was measured by biochemical methods. DNA was extracted then polymerase chain reaction was used to amplify KAT1 gene by specific primer designed based on sequence of KAT1 gene in GenBank. Also, tissue culture technique was applied using nine different combinations of hormones and different types of explant under salinity stress conditions. For in vitro selection of salt tolerant calli, callus of two genotypes cultured on different salt levels. RAPD- PCR were determined and analyzed. The result of growth parameters showed that plant height, leaf area, number of leaves and number of shoots reduced under high salt conditions. Statistical analysis showed significant increase in proline accumulation and Na+ concentration in Ismailia1 and Samnut 22, while Ca++, Mg++ and K+ decreased significantly in peanut genotypes under salt stress conditions. Sequence analysis confirmed presences of KAT1 gene in peanut and showed that Giza 6 and Ismailia1 shared in one SNP (A) in codon 195, while Ismailia1 and samnut 22 shared in SNPs (T) at codon 258, 259, 263 and 406. The best callus induction (80%) was observed in hypocotyl cultivated on MS medium containing 4 mgl-1 from 2, 4 D and 15 mgl-1 from kinetin for Ismailia1 and (70%) for Samnut 22. The large number of Ismailia 1 specific DNA marker was 7 in (1000 and 2000 ppm) and Samnut 22 specific DNA marker in (control, 2000, 3000, 4000 ppm) which was generated by primer OP-A7. These results showed high salt tolerance for Ismailia 1 and Samnut 22

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