Assessment and utilization of diversity in plant genetic resources is vital for the improvement of plant species. A sorghum diversity research set (SDRS) was developed by using SSR markers. A total of 320 sorghum accessions were selected based on geographic distribution from more than 3,500 germplasm accessions comprising Asia (East, Southeast, South and Southwest Asia) and Africa, conserved at NIAS Genebank, Japan. We selected 38 simple sequence repeats (SSR) markers which generated 146 alleles, covering ten chromosomes of sorghum from a three different published SSR linkage map of sorghum. The average percentage of polymorphic loci (P) and gene diversity (He) observed in this study were 82.8 and 0.217 respectively. Analysis showed a positive correlation with geographic pattern of differentiation. Based on SSR assessment, 107 sorghum accessions were selected as diversity research set. There was no significant difference in pattern of genetic spectrum between SDRS and base population. Similarly no greater change was observed for variability parameters (Dice, %P, He) and almost all of the SSR alleles were retained in selected sorghum accessions except for the loss of a single allele at locus Xtxp287. SDRS was sown during sorghum sowing season in two replications. Data were recorded on 26 important morphological traits according to the standard sorghum descriptors at Genebank. Analysis of variance showed a highly significant difference among all accessions for all of the traits. Morpho-agronomic traits could not effectively classify the accessions according to geographic origin by using cluster analysis.
Aegilops tauschii Coss. is the D-genome donor to hexaploid bread wheat (Triticum aestivum) and is the most promising wild species as a genetic resource for wheat breeding. To study the population structure and diversity of 81 Ae. tauschii accessions collected from various regions of its geographical distribution, the genomic representation of these lines were used to develop a diversity array technology (DArT) marker array. This Ae. tauschii array and a previously developed DArT wheat array were used to scan the genomes of the 81 accessions. Out of 7500 markers (5500 wheat and 2000 Ae. tauschii), 4449 were polymorphic (3776 wheat and 673 Ae. tauschii). Phylogenetic and population structure studies revealed that the accessions could be divided into three groups. The two Ae. tauschii subspecies could also be separately clustered, suggesting that the current taxonomy might be valid. DArT markers are effective to detect very small polymorphisms. The information obtained about Ae. tauschii in the current study could be useful for wheat breeding. In addition, the new DArT array from this Ae. tauschii population is expected to be an effective tool for hexaploid wheat studies.
Commiphora gileadensis and C. foliacea (family Burseraceae) are pantropical in nature and known for producing fragrant resin (myrrh). Both the tree species are economically and medicinally important however, least genomic understanding is available for this genus. Herein, we report the complete chloroplast genome sequences of C. gileadensis and C. foliacea and comparative analysis with related species (C. wightii and Boswellia sacra). A modified chloroplast DNA extraction method was adopted, followed with next generation sequencing, detailed bioinformatics and PCR analyses. The results revealed that the cp genome sizes of C. gileadensis and C. foliacea, are 160,268 and 160,249 bp, respectively, with classic quadripartite structures that comprises of inverted repeat’s pair. Overall, the organization of these cp genomes, GC contents, gene order, and codon usage were comparable to other cp genomes in angiosperm. Approximately, 198 and 175 perfect simple sequence repeats were detected in C. gileadensis and C. foliacea genomes, respectively. Similarly, 30 and 25 palindromic, 15 and 25 forward, and 20 and 25 tandem repeats were determined in both the cp genomes, respectively. Comparison of these complete cp genomes with C. wightii and B. sacra revealed significant sequence resemblance and comparatively highest deviation in intergenic spacers. The phylo-genomic comparison showed that C. gileadensis and C. foliacea form a single clade with previously reported C. wightii and B. sacra from family Burseraceae. Current study reports for the first time the cp genomics of species from Commiphora, which could be helpful in understanding genetic diversity and phylogeny of this myrrh producing species.
Two hundred ninety-six Asian barley (Hordeum vulgare L.) accessions were assessed to detect QTLs underlying salt tolerance by association analysis using a 384 single nucleotide polymorphism (SNP) marker system. The experiment was laid out at the seedling stage in a hydroponic solution under control and 250 mM NaCl solution with three replications of four plants each. Salt tolerance was assessed by leaf injury score (LIS) and salt tolerance indices (STIs) of the number of leaves (NL), shoot length (SL), root length (RL), shoot dry weight (SDW) and root dry weight (RDW). LIS was scored from 1 to 5 according to the severity of necrosis and chlorosis observed on leaves. There was a wide variation in salt tolerance among Asian barley accessions. LIS and STI (SDW) were the most suitable traits for screening salt tolerance. Association was estimated between markers and traits to detect QTLs for LIS and STI (SDW). Seven significant QTLs were located on chromosomes 1H (2 QTLs), 2H (2 QTLs), 3H (1 QTL), 4H (1 QTL) and 5H (1 QTL). Five QTLs were associated with LIS and 2 QTLs with STI (SDW). Two QTLs associated with LIS were newly identified on chromosomes 3H and 4H.