Abstract:Orchidaceae is one of the most valuable plant groups all over the world, and is also an impressively large and complex family of flowering plants. Effective molecular tools used for the identification of orchid species should be developed to support traditional morphological approaches. This study reviews most of the DNA fragments that have been used as taxon identifiers in researches conducted on Orchidaceae in order to assess potential molecular markers and metric measurements for the identification of orchid species.

Elucidation of the rice genome will not only broaden our understanding of genetic characterization of the agronomic characteristics but also facilitate the rice genetic improvement through marker assisted breeding. However, the genome resources of aromatic rice varieties are largely unexploited. Therefore, the whole genome of two elite aromatic traditional japonica rice landraces in North Vietnam, Tam Xoan Bac Ninh (TXBN), and Tam Xoan Hai Hau (TXHH), was sequenced to identify their genome-wide polymorphisms. Overall, we identified over 40,000 novel polymorphisms in each aromatic rice landrace. Although a discontinuous 8-bp deletion and an A/T SNP just upstream the 5-bp deletion in exon 7 of BADH2 gene were present in both rice landraces, the number of SNP high resolution regions of TXBN was six times higher than that of TXHH. Furthermore, several hot spot regions of novel SNPs and indels were found in both genomes, providing their potential gene pools related to aroma formation. The genomic information of two aromatic rice landraces described in this study will facilitate the identification of fragrance-related genes and the genetic improvement of rice.

Salinity is one of the major abiotic stresses, and it limits rice production in many worldwide areas. A lot of attention has been paid to developing rice salinity tolerance to cope with climate change. This study is based on the genome sequence databases of 36 Vietnamese landraces. The candidate gene, SRWD2, has been predicted and identified. The salt responsive WD40 protein 2 is involved in salt tolerance yield of nine rice landraces. Specifically, nine homologous segments of the sequences were found to be components of the CSD nucleotides, which is shown to be similar to the reference genome LOC _ Os02g48964.1 and LOC _Os02g48964.1 CDS, respectively. At the same time, the functional marker, SRWD2add14, was designed to identify the candidate gene, SRWD2, based on its size as 150 bp (candidate gene tolerant to salinity) and 136 bp (different sequences to compare SRWD2-reference genome sequence). The findings show that Mot bui do landrace carries the candidate gene, SRWD2 (homozygote). The rice genotype should be used as a potential material for rice breeding to develop salt tolerance in rice varieties.