Cucurbita maxima Duch. is one of the most morphologically variable cultivated species. The Center for Conservation and Breeding of the Agricultural Diversity (COMAV) holds a diverse germplasm collection of the Cucurbita genus, with more than 300 landraces of this species. Morphological and molecular characterization are needed to facilitate farmer and breeder use of this collection. With this aim, the morphological variation of a collection of 120 C. maxima accessions was evaluated. The majority of these accessions originated from Spain, which has acted as a bridge since the 16th century for spreading squash morphotypes between the Americas and Europe. South American landraces (the center of origin of this species) were also included. Eight morphological types were established based on this characterization and previous intraspecific classifications. A subset of these accessions, selected from these classification and passport data, was employed for molecular characterization. Two marker types were used; sequence related amplified polymorphism (SRAP), which preferentially amplifies open reading frames (ORF), and amplified fragment length polymorphism (AFLP). In the main, SRAP marker analysis grouped accessions in accordance to their type of use (agronomic traits) and AFLP marker analysis grouped accessions as to their geographical origin. AFLP marker analysis detected a greater genetic variability among American than among Spanish accessions. This is likely due to a genetic bottleneck that may have occurred during the introduction of squash into Europe. The disparity of the results obtained with the two markers may be related to the different genome coverage which is characteristic of each particular marker type and/or to its efficiency in sampling variation in a population.
María Ferriol, Belén Picó, and Fernando Nuez
Xinyi Zhang, Li Liao, Zhiyong Wang, Changjun Bai, and Jianxiu Liu
Quiros, 2001 ; Uzun et al., 2009 ). Combination of ISSR and SRAP markers has been used for assessment of genetic diversity among diverse species, such as Dianthus L. species and Salvia miltiorrhiza Bunge ( Budak et al., 2004a ; Li et al., 2014
Amnon Levi and Claude E. Thomas
sequence repeat (ISSR), amplified fragment length polymorphism (AFLP), and sequence-related amplified polymorphism (SRAP) markers ( Levi et al., 2006 ). In this study, markers from different linkage groups of the watermelon genetic linkage map ( Levi et
Xiu Cai Fan, Hai Sheng Sun, Ying Zhang, Jian Fu Jiang, Min Li, and Chong Huai Liu
0940♂, and Fu’an-ci-01 using SSR markers. Both SSR and SRAP markers can be used to identify homonyms. The result will be valuable for further management and protection of wild V. davidii germplasm resources. Literature Cited Abedian, M. Talebi, M
Vanina Cravero, Eugenia Martín, and Enrique Cointry
and less complicated than AFLPs ( Budak et al., 2004 ). The objectives of this research were to determine if SRAP markers could be used to evaluate genetic diversity in a C. cardunculus collection and to reveal the genetic distances between
Yan Liu, Hailin Guo, Yi Wang, Jingang Shi, Dandan Li, Zhiyong Wang, and Jianxiu Liu
of the genus Paspalum ( Jarret et al., 1998 ; Liu et al., 1995 ; Xie, 2004 ). Compared with morphological analysis, the genetic variance at the molecular level is not influenced by environmental factors. SRAP markers have the advantages of
Longzhou Liu, Youyuan Chen, Zhenghong Su, Hui Zhang, and Weiming Zhu
chain reaction (PCR) products may be separated on polyacrylamide gels for further sequencing and analysis ( Li and Quiros, 2001 ). SRAP markers are, however, expensive and technically demanding, which makes them less useful for large-scale MAS. Simple
H. Budak, R.C. Shearman, R.E. Gaussoin, and I. Dweikat
A simple marker technique called sequence-related amplified polymorphism (SRAP) provides a useful tool for estimation of genetic diversity and phenetic relationships in natural and domesticated populations. Previous studies and our initial screen showed SRAP is highly polymorphic and more informative when compared to AFLP, RAPD and SSR markers. In this study, applicability of the SRAP markers to obtain an overview of genetic diversity and phenetic relationships present among cool-season (C3) and warm-season (C4) turfgrass species and their relationship with other Gramineae species were tested. Phenetic trees based on genetic similarities (UPGMA, N-J) were consistent with known taxonomic relationships. In some cases, well-supported relationships as well as evidence by genetic reticulation could be inferred. There was widespread genetic variation among C3 and C4 turfgrass species. In Dice based cophenetic matrix, genetic similarities among all species studied ranged from 0.08 to 0.94, whereas in Jaccard based cophenetic matrix, genetic similarities ranged from 0.05 to 0.85. C3 and C4 species were clearly distinguishable and a close relationship between italian ryegrass and tall fescue were obtained based on SRAP. Genome structures of turfgrasses are comparable to other Gramineae species. This research indicates that the SRAP markers are useful for estimating genetic relationships in a wide range of turfgrass species. The SRAP markers identified in this study can provide a useful reference for future turfgrass breeding efforts.
O. Gulsen, R.C. Shearman, K.P. Vogel, D.J. Lee, P.S. Baenziger, T.M. Heng-Moss, and H. Budak
Buffalograss [Buchloe dactyloides (Nutt.) Engelm.] has the potential for increased use as a turfgrass species due to its low maintenance and water conservation characteristics. This study was conducted to estimate diversity and relationships among naturally occurring buffalograss genotypes based on the nuclear genome, using sequence-related amplified polymorphism (SRAP) markers. The 56 genotypes studied represented five ploidy levels collected from diverse geographic locations in the North American Great Plains. In addition, blue grama [Bouteloua gracilis (H.B.K.) Lag. Ex Steud.] and perennial ryegrass (Lolium perenne L.) were included as outgroups. Twenty-five combinations of forward and reverse primers were used. Ninety-five intensively amplified markers were scored and used to infer diversity and relationships among the genotypes. All buffalograss genotypes were discriminated from each other with similarity values ranging from 0.70 to 0.95. Principal component analysis (PCA) suggested that the 56 genotypes could be reduced to 50 due to high similarity levels among some of the genotypes. The distance between buffalograsses, blue grama, and perennial ryegrass were consistent with current taxonomical distances. This research indicates that SRAP markers can be used to estimate genetic diversity and relationships among naturally occurring buffalograss genotypes.
Riaz Ahmad, Dan Potter, and Stephen M. Southwick
Simple sequence repeat (SSR) and sequence related amplified polymorphism (SRAP) molecular markers were evaluated for detecting intraspecific variation in 38 commercially important peach and nectarine (Prunus persica) cultivars. Out of the 20 SSR primer pairs 17 were previously developed in sweet cherry and three in peach. The number of putative alleles revealed by SSR primer pairs ranged from one to five showing a low level of genetic variability among these cultivars. The average number of alleles per locus was 2.2. About 76% of cherry primers produced amplification products in peach and nectarine, showing a congeneric relationship within Prunus species. Only nine cultivars out of the 38 cultivars could be uniquely identified by the SSR markers. For SRAP, the number of fragments produced was highly variable, ranging from 10 to 33 with an average of 21.8 per primer combination. Ten primer combinations resulted in 49 polymorphic fragments in this closely related set of peaches and nectarines. Thirty out of the 38 peach and nectarine cultivars were identified by unique SRAP fingerprints. UPGMA Cluster analysis based on the SSR and SRAP polymorphic fragments was performed; the relationships inferred are discussed with reference to the pomological characteristics and pedigree of these cultivars. The results indicated that SSR and SRAP markers can be used to distinguish the genetically very close peach and nectarine cultivars as a complement to traditional pomological studies. However, for fingerprinting, SRAP markers appear to be much more effective, quicker and less expensive to develop than are SSR markers.