Search

Tomato (Lycopersicon esculentum Mill.) are considered major and important globally vegetable crops and in Egypt in particular. Tissue culture techniques have encouraged the utilization of mutation methods in crop improvement. The mutation induction in vegetative crops through tissue culture may be the optimal method to improve these crops. Induced genetic variation in tomato plantlets by using gamma radiation and identified these changes through SCoT and ISSR markers. Egyptian tomato cultivar Idkawy explant was cultured onto MS medium supplemented with 0.2 mg-l BAP. The resulted plantlets were irradiated with γ radiation doses (50, 100, 150, 200 or 250 Gy). The survival, growth rate, and mean of shoot length were decreased with increasing gamma radiation dose. The irradiated plantlets survival percentages were ranged from 78.75% to (50 Gy) and 18.75% to (250 Gy), whereas, the shoot length decreased by a rate of 2.71 cm for the dose (50 Gy) and 1.2 cm for dose (250 Gy). Genetic diversity was evaluated by SCoT and ISSR markers using ten primers for each. It was noticed that the polymorphism percentage mean of SCoT marker (60.53%) is higher than the ISSR marker (39.6). The PIC values average for both markers SCoT and ISSR were 0.429 and 0.347, as well, MI values were 0.345 and 0.156, respectively. On the other hand, the effective no. of alleles (Ne), Nei's genetic diversity (H) and Shannon's information index (I) parameters, it was found that the dose 100 Gy caused the highest genetic variation compared with other doses using SCoT marker, however, in ISSR marker was dose of 150 Gy the highest dose for induced genetic variation. The obtained results demonstrate that SCoT marker was more accurate and efficient than ISSR marker for distinguishing and genetic variation analysis of irradiated tomato plantlets. The relationships within treatments were assessed through cluster analysis (UPGMA) based on SCoT and ISSR analysis. [ABSTRACT FROM AUTHOR]

The fundamental objective of any successful breeding program is releasing divergent cultivars adapted to every region’s requirements all over the country. The traditional method for estimating genetic diversity is morphological characterization. The polymorphism based DNA characterization recently has been emerged as a suitable tool in estimating genetic diversity. The present study included 14 Egyptian bread wheat cultivars. This investigation conducted at Shandaweel Agricultural Research Station, Agricultural Research Center, Egypt during two growing seasons 2016/2017 and 2017/2018. The genetic diversity estimated based on 17 morphological characters as well as 21 microsatellite markers i.e. SSR markers. The phenotypic results indicated significant and highly significant differences among the studied cultivars. Based on the morphological data the principal component analysis (PCA) computed where it revealed that the first principal component (PC1) and the second principal component (PC2), explained 49.31 % of the total variability. PC1 and PC2 used to construct genotype by trait biplot (GT biplot) to group the cultivars into different groups. In the same context, the genetic variability estimated using microsatellite markers; the results revealed that high polymorphism information content (PIC) and high marker index (MI) were found. High variation were found in A and B genomes rather than D genome. Genetic similarity matrix (Jaccard coefficient) was computed based on the presence and absence of SSR marker bands. Similarity matrix showed that the highest similarity (0.620) was found between Giza 171 and Giza 168 cultivars and the lowest similarity (0.250) was found between Shandaweel 1 and Misr 3 cultivars. The dendrogram constructed based on similarity matrix and it clustered the cultivars into three main groups. The correlation coefficient (Pearson coefficient) between individual characters and markers show strong, positive, and significant correlation between specific markers and particular characters suggesting that each of these specific markers is a candidate linked marker for this particular character to be used in Markers Assisted Selection (MAS). The similarity among cultivars based on morphological characters showed a narrow range, whereas the similarity among cultivars based on SSR showed a broad range. The similarity based SSR markers was more accurate and informative than morphological characters basis. This investigation reveals that SSR markers are well utilized in estimating genetic diversity. [ABSTRACT FROM AUTHOR]

Context: The role of the angiotensin II type 1 receptor (AT1R) gene polymorphism, A1166C, has been shown to be associated with end stage renal disease (ESRD) and its progression. There is also some evidence that HLA class II alleles are associated with ESRD independent of other factors., Objective: To examine the association between AT1R gene polymorphism in the susceptibility and progression to ESRD in patients with chronic renal failure and to investigate if the AT1R genotypes and HLA-DR alleles predict the time to ESRD., Materials and Methods: Genotyping was performed in 50 ESRD patients and 44 control subjects for the AT1R A1166C gene polymorphism using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). ESRD patients were examined for HLA-DRB1 alleles according to a reverse hybridization line probe assay., Results: Allele and genotype frequencies of the AT1R polymorphism did not differ significantly between ESRD patients and controls. Furthermore, there was no association between the AT1R gene polymorphism or HLA-DRB1 alleles with the time to the occurrence of end stage failure., Discussion and Conclusion: We concluded that the AT1R genotype does not contribute to the genetic susceptibility of ESRD and is not associated with progression of chronic kidney failure to ESRD.