Genetic relationship of interspecies for eight birch species

Genetic relationships of eight species of genus Betula were evaluated using ISSR marks. A total of 236 loci were generated from 17 ISSR primers. Percentage of polymorphic bands (PPB) varied from 5.93 to 19.92. The highest and the lowest level of genetic differentiation were detected in B. ovalifolia and B. maximowicziana Regel respectively. In these eight species, genetic diversity of birch (HT) was 24.38 %, and the genetic variation (GST ) interspecies was accounting for 79.36% of total genetic variation. According to the cluster results of genetic distance, the eight species were classified into three groups as B. davurica, B. ovalifolia, B. platyphylla and B. pendula for one group; B. schmidtii, B. costata and B. ermanii Cham. var. communis for one group, and B. maximowicziana Regel for another group. The result of cluster is consistent with traditional morphological classification.

Informative ISSR Markers Help Identify Genetically Distinct Accessions of Oryza rufipogon in Yield Improvement

Inter simple sequence repeat（ISSR） polymorphism was used to determine genetic diversity and phylogenetic relationships in 90 genotypes of wild and cultivated species of Oryza from different geographical regions of the world. In all the 17 primers used in ISSR-PCR, a total of 11 464 bands were amplified at 253 band positions/loci. The primer UBC-809 amplified the maximum bands（1 059） at 21 band positions. UBC-810 and UBC-835 amplified the minimum of 391 bands each at 7 and 14 band positions, respectively. The mean polymorphism information content ranged from 0.44 to 0.84 and resolving power ranged from 8.69 to 23.53. Un-weighted pair group method with arithmetic mean dendrogram and population structure based on the 17 primers separated all genotypes into 4 major clusters with a genetic similarity of 53%–100%. The first two clusters consisted of 30 O. rufipogon accessions each. In the third cluster, O. nivara and O. longistaminata grouped as one sub-cluster and all other O. nivara accessions and cultivars grouped as another sub-cluster. The fourth cluster had only five O. rufipogon accessions which can be a source of new genes. Four sub-populations were identified within O. rufipogon and two sub-populations within O. nivara at K = 7. A subset of six primers with high resolving power values were the most informative and grouped all genotypes almost similarly as the 17 primers did. Use of these six highly informative primers in ISSR-PCR is a cost effective and robust method for assessing genetic diversity in large germplasm collections of wild rice species.

ISSR Markers as a Tool for Assessing Genetic Diversity in the Chinese Alligator (Alligator sinensis)

Eight different inter simple sequence repeat(ISSR) markers were used as tools to investigate genetic variability and population differentiation in the Chinese alligator,Alligator sinensis,in this study. Eleven polymorphic bands(17.2%) out of a total of 64 were generated from 110 individuals in three populations. Analysis of molecular variation showed that most of the genetic variation(98.0%) occurred within the populations. Dendrogram relationship based on Nei’s unbiased genetic diversity illustrated that two breeding populations were genetically closely related. The Nm value of the study was 4.520,suggesting that high levels of gene flow existed and no differentiation appeared in the populations. In a reconstructed Neighbor-Joining tree,the haplotypes coming from the same populations did not gather as a class,suggesting the three populations had no apparent geographic pattern. This study shows that ISSR markers could be well applied as a feasible tool to assess genetic diversity in Chinese alligator individuals.

Genetic Structure of Tetraploid Italian and Westerwolds Ryegrasses （Lolium spp,） as Revealed by Enzyme and ISSR Polymorphism

The genetic variation of Italian ryegrass （Lolium multiflorum Lain.） and westerwolds ryegrass （L. westerwoldicum Breakw.） was investigated in eight tetraploid cultivars originated from Poland. The 337 individual seedlings, cultivated in uniform greenhouse conditions, were tested with horizontal gel electrophoresis according to five enzyme systems： diaforase （DIA）, superoxide dismutase （SOD）, glutamate oxalacetate transaminase （GOT）, peroxidise （PX） and phosphogluco isomerise （PGI）, which were used to array allelic diversity at five polymorphic loci. The estimation of genetic diversity in 64 plants of the same cultivars was studied using inter simple sequence repeats （ISSRs） as molecular marker. The genetic variation described by ISSR suggests that the polymorphism detected appears to be poorly informative at the taxonomic level. For statistical analysis, unweighted pair group method with arithmetic mean （UPGMA） based dendrograms and minimum spanning trees were constructed using Nei＇s distance and Jaccard＇ s similarity coefficient.

ISSR Fingerprinting to Ascertain the Genetic Relationship of Curcuma sp. of Tripura

Molecular fingerprints of four different species of Curcuma, viz., C. amada, C. caesia, C. longa and C. zedoaria, found in Tripura were developed using Inter Simple Sequence Repeats. Twenty ISSR primers generated 116 loci amplified in the range of 200 - 5000 bp with an average of 5.8 alleles and 1.6 effective alleles per locus. The percentage of polymorphic band was found to be 86.29 with an average of 5.15 per primer. Based on UPGMA algorithm these four species are placed in two different clusters that validate the classification based on external and internal morphological characters. The polymorphic ISSR markers generated from this study will be useful for understanding the genetic relationship of different species of the genus Curcuma.