S ILICON (Si) is beneficial for plant growth and has the potential to alleviate the deleterious effects of heavy metals in plants grown on contaminated soils. This study aimed to evaluate the adaptive mechanisms induced by Si application (1mM sodium meta-silicate, Na 2 O 3 Si.9H 2 Ox) in Triticum aestivum L. plants subjected to cadmium (Cd) stress (100 and 200µM CdSO 4 ). Under Cd stress, Si application significantly increased plant biomass, relative water content, nutrient uptake, and allocation as well as Si content while it decreased Cd accumulation compared to Cd-stressed plants. Si application also induced lignin content, mainly in roots, in the presence or absence of Cd in comparison to controls. Cd stress significantly increased the accumulation of oxalate, malate and citrate contents in the roots in comparison to control, whereas Si supplementation increased malate, and citrate in shoots. Additionally, Cd-induced oxidative stress designated by the increment of malondialdehyde, H 2 O 2 contents and electrolyte leakage was diminished upon Si application. Concomitantly, Cd-stress markedly enhanced glutathione reductase (GR), glutathione peroxidase (GSHPx), and ascorbate peroxidase (APx) while GSH/GSSG and ASA/DHASA ratios decreased. Si application significantly induced all tested antioxidant enzymes and increased GSH/ GSSG and ASA/DHASA ratios. Interestingly, low-affinity Cd transporter (LCT1), ATPase/heavy metal transporter (HMA2), and phytochelatine synthase (PCs) genes expression decreased in the shoots and roots of Si+ Cd-treated plants, while that of Si transporter (Si1) markedly increased, which may contribute to Cd uptake reduction and increased Si content. Taken together, the results highlight the role of Si in alleviating the adverse effect of Cd on wheat plants.

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The application of molecular methods as complementary or alternative methods can help identifying the plants containing the resistance gene at genotypic level. Therefore, DNA markers can be useful tools for selecting resistant genotypes and can save the evaluation time and improve the precisions. Selection takes productive and genetic lines resistant to nematodes have been known in sugar beet genotypes by Polymerase chain reaction (PCR). Sugar beet (Beta vulgaris L.) is the greatest vital crops that standing following to sugar cane as sugar crop in the world, later it produces about 20 % of sucrose production annually in the world. In Egypt, Sugar beet is cultivated in 523188 faddans with an average production of 20.7 tons per faddan. Recently, reclaimed desert irrigated lands at West Nubaryia and El-Bostan regions has shown that sugar beet can be successfully grown under sandy soil area condition and its considered as the extended area for sugar beet production in Egypt. The most serious problem against sugar beet extension in new lands is root-knot nematode, Meloidogyne incognita and Meloidogyne javanica which were reported as major nematode pests of sugar beet in Egypt. Importance of employed resistance nematode sugar beet genotypes (cultivars/hybrids) in infested areas has a great concern.The present study was carried out during the growing season 2015 -2016 at pots experiment in Sabahia Agricultural Research Station, Alexandria, Egypt, for evaluating the reaction of seventeen sugar beet genotypes against the most serious nematode, (Meloidogyne incognita). The seventeen sugar beet genotypes tested in this test were twelve sugar beet commercial varieties, three sugar beet inbred lines and two sugar beet breeding materials. Computed damage index classified the seventeen sugar beet genotypes into five categories according to the varietal assessment. (Four were resistant(R), three were moderately resistant (MR), six were tolerant (T), two were susceptible (S) and two were hyper susceptible (HYS)). The results for conventional PCR indicated that genes of Hs1pro-1and HSPRO2 shows resistance to, (Meloidogyne incognita) beside the known function of these genes as resistant against cyst nematode (Heterodera schachtii). Mi-1.2 gene consider resistance to root knot nematode (Meloidogyne incognita) was found in (Mi-3) inbred line.

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Molecular analysis is an easier means to identify and isolate a specific gene which has imperative function for growth, body composition , fat deposition, metabolic and skeletal traits as well as the molecular genetics selection on individual genes is a very efficient method to genetically improve economically important traits in chickens. Insulin- like growth factor 1 ( IGF-1)is a member of a heterogeneous group of peptides with important growth.Transforming growth factorβ ( TGF-β) belongs to a large family of growth and differentiation factors that play a pivotal role in a great variety of biological activities including morphogenesis, development and differentiation. DNA was extracted from 48 chickens sampled from three strains Lohman (17) , Sinai (24) and Gimmizah (7) IGF-1 gene and TGFβ2 gene were amplified using PCR protocol. Electrophoresis was carried out on the products of PCR , bands viewed on transilluminator. The size of IGF-1 gene was 675 bp while the size of TGFβ2 gene was 188bp. Sharp bands were purified and sequenced and used the dendrogram to show the relationships between other vertebrate species

Type II maize callus of the HiII genotype can be separated into regenerable and non-regenerable types based on the visible morphology of the callus. When the nonregenerable morphotype of callus initiated 6 mo or a yr earlier was treated with from 2% to 20% polyethylene glycol (PEG; 3,350 molecular weight) for three subculture periods of 21 d each, the morphotype changed to regenerable, and the callus did become highly regenerable. The PEG treatments did not improve the plant regeneration ability of the regenerable morphotype or of an old culture initiated 4 yr earlier.

Two maize populations (GE440 £ Sd7 and NC300 £ Gm1002) were used in this study. Molecular markers like simple sequence repeat (SSR) and sequence-tagged site (STS) were used to identify resistance genes linked to Fusarium ear rot (Fusarium verticillioides). Also, quantitative trait locus (QTL) mapping was used to detect resistance genes on maize chromosomes. The co-dominant microsatellite markers (bnlg1063, umc2082, bnlg1621, umc2013, bnlg1740, umc2059 and SSR85) and STS (STS06) were amplified polymorphic bands and candidate markers linked to Fusarium ear rot resistance genes in maize. Seven QTLs were identified ranging from 2 to 7 for each trait. QTLs were distributed on two chromosomes and associated with grain yield/main ear and 100 kernel weight. The present study indicated that microsatellite and STS primers might be useful for developing improved cultivars.

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