RAPD markers have been used successfully in genetic analysis of several crop plants. This method poses difficulties with a highly heterozygous species such as Theobroma cacao because of the dominant phenotypic expression of bands. A backcross family derived from ctultivars Catongo and Pound 12 was analyzed to determine the efficacy of RAPD markers in analyzing cacao populations. A preliminary screen of the parents and the F1 plant used as the backcross parent was conducted with 180 RAPD primers; of these, 26% were polymorphic and reproducible and produced 104 storable loci. Genomic DNA from 54 individuals of the backcross population was then amplified with these primers; 68.3 % of the loci segregated as expected in a Mendelian fashion. Separation of RAPD fragments on acrylamide revealed an additional polymorphic locus from one primer that was indistinguishable on agarose. The results demonstrated that RAPD markers can be used to study the cacao genome.
C.M. Ronning, R.J. Schnell and D.N. Kuhn
Robert D. Marquard, Eric P. Davis and Emily L. Stowe
Forty selections, including 37 cultivars of Hamamelis spp., were evaluated for genetic similarities using randomly amplified polymorphic DNA (RAPD) markers. Cluster analysis identified seven groups, which included three groups of H. ×intermedia cultivars, two groups of H. vernalis, and one group each of H. mollis and H. japonica. Three H. ×intermedia cultivars, `Arnold Promise', `Westerstede', and `Carmine Red', did not group closely with the other 20 cultivars of H. ×intermedia. Selections of the North American species H. vernalis were quite distinct from the Asiatic selections. However, data are presented that suggest hybridization exist between Asiatic Hamamelis spp. and H. vernalis. Genetic similarities between known half-sib families provides evidence that the cultivar pairs `Arnold Promise'—`Winter Beauty' and `Carmine Red'—`Hiltingbury' are, themselves, not likely half-sibs.
Patrick J. Conner and Bruce W. Wood
Genetic variation among pecan [Carya illinoinensis (Wangenh.) C. Koch] cultivars was studied using randomly amplified polymorphic DNA (RAPD) markers. Using a combination of primers, a unique fingerprint is presented for each of the pecan genotypes studied. The genetic relatedness between 43 cultivars was estimated using 100 RAPD markers. Genetic distances, based on the similarity coefficient of Nei & Li, varied from 0.91 to 0.46, with an average value of 0.66 among all cultivars. The phenetic dendrogram developed from cluster analysis showed relatively weak grouping association. However, cultivars with known pedigrees usually grouped with at least one of the parents and genetic similarity estimates appear to agree with known genetic relationships.
Youngjae Oh, Jason D. Zurn, Nahla Bassil, Patrick P. Edger, Steven J. Knapp, Vance M. Whitaker and Seonghee Lee
develop practical tools for crop improvement. DNA tests are tools that help breeders predict traits of interest in parents and offspring, and how they will be inherited in future generations. The RosBREED project ( https://www.rosbreed.org ), funded by U
Seth D. Wannemuehler, James J. Luby, Chengyan Yue, David S. Bedford, R. Karina Gallardo and Vicki A. McCracken
et al., 2012 . Advances in DNA technologies for crop improvement have increased breeders’ ability to adapt their selection processes to meet dynamic market demands. One such DNA technology is marker-assisted selection (MAS), which allows breeders to
Amnon Levi, William P. Wechter, Karen R. Harris, Angela R. Davis and Zhangjun Fei
heirloom cultivars. The use of randomly amplified polymorphic DNA (RAPD) primers produced a low number of polymorphic markers among watermelon heirloom cultivars ( Levi et al., 2001 ). In a recent study, 1309 RAPD primers were screened to identify
Juan Chen, Nianhe Xia, Xiaoming Wang, Richard C. Beeson Jr. and Jianjun Chen
. Polyploidy occurs in the genus Lonicera ( Ammal and Saunders, 1952 ; Solov’eva and Plekhanova, 2003 ). Ploidy levels and genome sizes play important roles in plant evolution ( Soltis et al., 2003 ). The 2C nuclear DNA amount of Lonicera varies 6-fold
Marie-José Côté and Lisa Leduc
accurate identification becomes difficult. DNA fingerprinting techniques have been proven to be reliable for cultivar identification because the markers are not influenced by environmental factors, life stage, or type of plant tissue analyzed. The choice
Barbara S. Gilmore, Nahla V. Bassil, Danny L. Barney, Brian J. Knaus and Kim E. Hummer
species of little economic importance (reviewed in Zalapa et al., 2012 ). For example, DNA sequencing using next-generation sequencing technology (Ilumina platform ® ; Ilumina, San Diego, CA) allowed development of polymorphic SSR markers for alaska
Paul A. Wiersma, Deniz Erogul and Shawkat Ali
that is available with DNA marker technologies. Although a similar study had been carried out with amplified fragment length polymorphism (AFLP) markers ( Zhou et al., 2002 ) it was determined that the level of hands-on expertise required to run and