In this paper, the genetic diversities of 12 rice genotypes (Oryza sativa L.), representing Indica, Japonica, and Indica–Japonica varieties, were assessed using twelve ISSR and five SSR markers. In addition, the rice genotypes were evaluated for 11 agro-morphological traits in a two-year trial. Association mapping was performed to detect any association between the DNA markers and the agro-morphological traits. An association analysis was conducted considering the relative kinship among the genotypes and accounting for the population structure using the unified mixed-model approach to avoid possible false-positive associations. Seventy-three alleles were collectively produced by ISSRs and SSRs, with an average of 6.3 and 2.8 alleles per locus, respectively. Both marker systems were informative, and the average polymorphism information content (PIC) was 0.222 and 0.352 for ISSRs and SSRs, respectively. The average expected heterozygosity (H_exp) was 0.264 for ISSRs compared to 0.457 for SSRs. After using the false discovery rate (FDR) method, the association analysis revealed a total of 12 significant marker–trait associations with six agro-morphological traits, including the no. of unfiled grains panicle⁻¹, panicle length, panicle weight, the no. of panicles plant⁻¹, the no. of tillers plant⁻¹, and 1000-grain weight. ISSRs showed seven significant associations with five markers, while SSRs showed three significant associations with three markers. The phenotypic variance (R²) explained by each marker ranged between 29.2% for the ISSR marker HB11 (associated with 1000-grain weight) and 49.3% for the ISSR marker HB8 (associated with the no. of tillers plant⁻¹). The identified marker–trait associations reported herein may improve the expected gain of future molecular-based rice-breeding programs, particularly those designed for improving grain-related or harvest-related traits.

Background: The phylogeny and phylogenetic relationships of Trichoderma species were investigated by many methods including maximum parsimony and distance analysis of DNA sequences from multiple genetic loci. 5.8S rDNA sequence analysis is a powerful tool in evolution studies. Main body: The aim of this study was to identify and determine the genetic distance between 36 Trichoderma isolates from Egyptian and Saudi Arabian soils based on their 5.8S rDNA sequences. The genetic diversity of Trichoderma (Hypocreales, Ascomycota) species from Egypt and Saudi Arabia was investigated. The DNA barcoding of 36 isolates, based on the internal transcribed spacers 1 and 4 (ITS1 and 4) of the ribosomal RNA gene cluster and the partial sequence of this gene, revealed the diversity of these isolates. BLAST query showed that two species, namely T. longibarchiatum (42.7% of the isolates) and T. lentiforme (33.3% of the isolates), pre-dominated the isolates. Variation among specimens of the same species was detected. Cluster analysis of the Egyptian isolates showed two groups; the first group was subdivided into two subgroups, the first of which included T. lentiforme and T. crassum isolates, and the second subgroup harbored T. longibrachiatum, T. pseudokoningii, and T. bissettii. The second group included T. neokoningii and T. yunnanens. The cluster analysis of isolates from Saudi Arabia also consisted of two groups. The first group was subdivided into two subgroups; the first included T. longibrachiatum and T. pseudokoningii. The second subgroup harbored T. simmonsii and T. lentiforme. Also, no correlation between genetic and geographic distance was detected. Conclusion: The results of the present study indicated that the Saudi Arabian isolates showed greater nucleotide diversity compared to Egyptian isolates. Also, these findings will assist in future studies while assessing Trichoderma genetic diversity.

DNA barcoding is one of the powerful DNA-based identification tools that are used for accurate identification of a species. Despite several DNA barcodes were used, the accuracy and suitability of these barcodes depend on species-specific variations.The current study was conducted to compare the efficiency of two mitochondrial genes to the nuclear Internal Transcribed Spacer (ITS) region in the molecular identification of genus Dicentrarchus. A total of 80 fish samples for Dicentrarchus labrax and Dicentrarchus punctatus were randomly collected from two different locations in Egypt; Alexandria and Bardawil Lagoon. All samples were morphologically characterized. For species barcoding, the ITS region was firstly employed to carry out the PCR amplifications. Additionally, two mitochondrial genes; cytochrome b (Cyt b) and cytochrome oxidase subunit I (COI) were also used for species barcoding. To evaluate the efficiency of each marker, three different approaches were used. Firstly, phylogenetic relationship was constructed between the collected samples and a reference species using each genetic marker. Secondly, Automated Barcode Gap Discovery (ABGD) method was used for each marker in order to assign the samples into presumed species without priori species assumption. Lastly, the Poisson Tree Processes (PTP) model was used which relies on Bayesian support values to delimit species on the input tree. The two species of genus Dicentrarchus exhibited nearly similar ITS sequences, leading to an ambiguous identification of the two species. However, the two mitochondrial COI and Cyt b genes were able to accurately distinguish between the two species. The three approaches, phylogeny, ABGD and PTP presented consistent results. Overall, COI and Cyt b outperformed ITS in assigning species accurately. Mitochondrial barcodes could provide a leading guide for fish species identification. ITS should be abandoned in favor of COI and Cyt b as primary DNA barcode markers for fish species in general and Dicentrarchus genus, in particular.