Genomic DNA prepared from fruitbdies of 25 Grifola frondosa strains were amplified with the ITS primers and the PCR reaction products were enzymed. The ITS bands have same electrophoresis patterns but part of them have different restriction enzyme cutting site. These strains were divided into three broad categories. SRAP amplification employing 47 SRAP primer pairs were carried on and 138 polymorphic bands were detected. The phylogram tree showed that: ten strains were differentiated from the others effectively and fifteen strains have no obvious differences between each other. The results implied that the ITS-RFLP and SRAP markers were effective methods for strains identifica tion and germplasm evaluation but other markers were also needed to be used in conjunction.

Genetic variation within and among 12 populations of whip grass in south China were investigated using inter-simple sequence repeat (ISSR) and sequence-related amplified polymorphism (SRAP). High genetic diversity was found in whipgrass by two molecular makers (PPB=86.21%, I=0.357 based on ISSR; PPB=82.21%, I=0.352 based on SRAP). However, there was relatively low genetic diversity at population levels. A high degree of genetic differentiation among populations was detected based on different measures and different molecular markers. We also found that SRAP markers were more efficient than ISSR markers in this species. Based on these findings, sampling strategy was proposed for successfully utilizing the genetic resource of this species.

SRAP (Sequence-related amplified polymorphism) and ISSR (Inter simple sequence repeat) molecualr markers were used to evaluate the levels and patterns of genetic diversity among 45 collections of orchardgrass from four continents. Twenty-one primer combinations were used and 480 bands were produced in SRAP, of which 405(84.38%) were polymorphic. On the other hand, twelve primers were used to generate a total of 116 bands in ISSR, of which 116(87.07%) were polymorphic. The coefficient range of genetic similarity was 0.6248-0.9686 and 0.6116-0.9231 respectively. Based on cluster and principal component analysis on the genetic characteristics, all collections could be divided into four groups and five groups in two markers, respectively. According to the analysis of genetic diversity and relationships, the appropriate strategies for collection and conservation of germplasm resources also were discussed and scientific breeding with far genetic relationship materials in orchardgrass were suggested.

Genetic diversity among 28 Cymbidium varieties was evaluated by using a sequence-related amplified polymorphism (SRAP) marker system. The SRAP marker which was based on the open reading frames (ORFs) regions was developed primarily for Brassica species, but has been applied to various crops. A total of 30 SRAP primer combinations were initially screened. Twenty-eight SRAP primer combinations showed high polymorphism among the 28 Cymbidium varieties, which were consisted of breeding varieties and their parents in National Institute of Horticultural & Herbal Science (NIHHS). The amplified DNA fragments were separated by denaturing acrylamide gels and detected silver staining method. One hundred ninety six polymorphic bands (7 per primer) were generated and ranged from 0.3 to 1.0 kb in size. Polymorphic fragments were scored for calculating simple matching coefficient of genetic similarity and cluster analysis with multi-variate statistical package (MVSP) 3.1. The mean genetic similarity coefficient value was 0.588. The results showed that the correlation between F1 varieties and their parents was high. These studied SRAP markers will be useful tools for genotype identification, germplasm conservation, genetic relationships in Cymbidium.

We investigated genetic diversity among and within the populations of cultivated ginseng (Panax ginseng C. A. Meyer ) using SRAP profiles. A total of 24 ginseng plants were sampled from the three populations (two from China, one from Korea). Since all these populations are previously shown closely related to each other assister groups, we used Panax quinquefolium L. and wild ginseng as a reference species, which is not "within the sister group". All individuals from the three populations were screened with a total of 36 primer pairs with 26 primers generated from 328 SRAP bands of DNA gels. The mean gene diversity (HE) was estimated to be 0.057 within populations (range 0.032-0.067), and 0.086 at the species level. The genetic differentiation (Gst=0.31) indicates that genetic variation apportioned 30% among populations and 70% within populations. Generally, the result of this study indicates that ginseng contains high molecular variation in its populations.