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R ICE is very important crop in Egypt and the production of rice yield faced many challenges such as, saline soil and drought. For salinity about 30% of lands affected by salinity specially northern part of delta, besides, in Egypt the people increase continuously but the water sources are constant so year by year the problem increase. The rice cultivars differed in salinity and drought tolerance in the various stages of plant life, so, study of rice tolerance in germination and seedling stage play a vital role to rice breeder to select good rice donors to improve tolerance to salinity and drought. This investigation was carried out in the lab of Rice Research and Training Center (RRTC), Sakha station, Kafrelsheikh, Filed Crops Research Institute Egypt, during 2017 and 2018 seasons, to study the inheritance of some germination and early seedling traits associated with salinity and drought tolerance. Eight rice genotypes namely; Sakha102, Sakha104, Sakha105, Sakha106, Giza178, A22, IRAT170, and WAB56-125 were evaluated under salt solutions (NaCl) of distilled water as a control, 3.5 or 7dSm-1 salt concentrations according to the treatments and drought stress caused by two concentration of sorbitol (10 and 20 ml/l). Significant genetic variation was found among rice cultivars for seedling vigor under salt and drought stress conditions. Thus, could use the tolerance verities in breeding program to improved tolerance to salinity and drought. The phenotypic coefficient variability (PCV %) was higher than genotypic coefficient variability (GCV %) for all traits, indicating the existence of wide genetic variability among these genotypes. This study indicated that the rice variety A22 followed by WAB56-125 were the most tolerant to salt and drought stress conditions. Meanwhile, Sakha104 could use a good donor underwater deficit in breeding programs.

Rice (Oryza sativa, L.) is one of the strategic crops in Egypt, and the improvement of its productivity is an essential requirement to ensure food security. Salinity is one of the major environmental stresses that limit the productivity of rice crop. 14 SSR markers linked to salinity were used to study the genetic diversity within salinity tolerance QTLs in 18 rice genotypes. All the utilized primers were polymorphic, the number of alleles ranged from 2 to 6 with an average of 3.42 per locus. The major frequency alleles ranged from 0.33 to 0.78 for RM562 and RM412, respectively. The PIC values varied from 0.79 to 0.37 with an average of 0.50. Seven SSR markers i.e. RM562, RM493, RM1287, RM223, RM242, RM10720, and RM5 were informative markers with PIC values more than 50%. Jaccard's similarity coefficients ranged from 0.07 to 0.93 with an average of 0.45. The studied genotypes were grouped into two major clusters at 0.18 similarity. The PCA analysis had the ability to classify the studied genotypes into clearly four separate clusters based on the origin and salinity tolerance. 13 haplotypes other than the reference haplotype were identified. The number of genotypes per haplotype ranged from one to five. The current investigation highlighted the high amount of genetic diversity among the studied genotypes. Egyptian Yasmine, the fragrant genotype, was the most promising genotype where it has 50% of Pokkali alleles at Saltol QTL region and this makes it suitable to be used as salt tolerance donor for MAS in salinity tolerance molecular breeding program.

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