Driss Iraqi

Genetic diversity reduction in improved durum wheat cultivars of Morocco as revealed by microsatellite markers

It has been argued that genetic diversity in crop varieties has been on the decline in recent times due to plant breeding. This can have serious consequences for both the genetic vulnerability of crops and their plasticity when responding to changes in production environments. It is, therefore, vital for plant breeding programs to maintain sufficient diversity in the cultivars deployed for multi-period cultivation. In this study, to understand the temporal genetic diversity in durum wheat, 21 improved durum wheat cultivars released in Morocco, since 1956 and five exotic cultivars currently used in crossing programs were analyzed using 13 microsatellite markers. The analysis revealed a total of 44 alleles and average genetic diversity of 0.485 with genetic distances ranging from 0.077 to 0.846 at 13 microsatellite loci in Moroccan durum wheat cultivars. All the durum cultivars of Morocco could be distinguished using the 13 microsatellite markers. The total number of alleles and unique alleles were highest in cultivars developed before 1990, decreasing in cultivars developed during the 1990s and 2000s, indicating that recent durum breeding efforts have reduced allelic richness in recent cultivars. Thus, deployment of exotic durum wheat lines in breeding programs could enhance genetic diversity in durum wheat cultivars.

Correlation between the Chemical and Genetic Relationships among Thymus saturejoides Genotypes Cultured under in vitro and in vivo Environments.

In this study, the in vitro and in vivo essential oil (EO) composition and genetic variability in six micropropagated genotypes of Thymus saturejoides Coss., a Mediterranean medicinal and aromatic plant, were analyzed by GC/MS and randomly amplified polymorphic DNA (RAPD). Yield and composition of the EO varied between genotypes. Cluster analysis based on RAPD data and EO grouped the six genotypes in three groups in both culture conditions, thus showing considerable intraspecific genetic and chemical variations. Applying the Mantel test, the result showed a significant correlation between the two proximity matrices RAPD and EO obtained from in vitro genotypes, whereas this correlation was not observed when using the EO obtained from the in vivo genotypes.

Development of specific primers for the detection of HVA1 from barley in transgenic durum wheat by polymerase chain reaction (PCR) technology

Genetic transformation is a widely employed tool in both basic research and commercial plant breeding programs. Its application requires that transgenes be stably integrated and expressed in the plant genome. When transgenic plants are developed, it is essential to determine which plants contain the transgene. Detection methods are usually based on amplification of the target transgene. This paper describes a development of detection method based on conventional and real time polymerase chain reaction (PCR) for simultaneous detection of barley HVA1 transgene and its transcript in transformed durum wheat. Since there exist a high homology between the barley HVA1 gene and the wheat gene, development of a specific sets of primers is needed for PCR-based characterizations, and the study of the transgene. Based on the alignment of the two genes sequences obtained from public databases, several primers were designed to detect and distinguish between the transformed and non-transformed plants. Real time PCR has been employed because of its inherent sensitivity and quantitative nature. It has been possible to design the following primers pairs F2/MMR, F2/R10 and F14/R10 as highly specific and suitable for the detection of HVA1 DNA by conventional and real-time PCR. Nonetheless, the primers used were allowed to reach high efficiencies and did not show any cross-reactivity with DNAs extracted from various plants. The sensitivity achieved was 6.4 pg. The primer pair F2/R10 was considered as highly specific for the detection of both DNA and mRNA of the HVA1 by real-time PCR. The assays proved to be accurate, specific, sensitive and sufficiently reproducible for further application in high-throughput molecular characterization of transgenic lines. Key words: HVA1, durum wheat, transgenic plant, real time polymerase chain reaction (PCR), drought.