|RAWLS, BERNESSA - Feagin Mill Middle School|
|DHEKNEY, SADANAND - University Of Wyoming|
|SITTHER, VIJI - Morgan State University|
Submitted to: American Journal of Plant Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/31/2015
Publication Date: 9/23/2015
Citation: Rawls, B., Harris-Shultz, K.R., Dhekney, S., Sitther, V. 2015. Analyzing clonal fidelity of micropropagated Psidium guajava L. plants using simple sequence repeat markers. American Journal of Plant Sciences. 6:2385-2392.
Interpretive Summary: Guava is grown in tropical and subtropical regions throughout the world and is an excellent source of vitamins, minerals, and polyphenolic antioxidants. Because of the increasing awareness of its health benefits, there is an increase in demand for guava production. Guava is primarily commercially propagated by seeds as vegetative propagation can be cumbersome due to the absence of a taproot. Thus use of tissue culture is a viable alternative to increase plant material with desirable attributes (i.e. insect and disease resistance, low amount of seeds in fruit, etc). In this study the conditions for micropropagation of guava cultivar Lucknow 49 was optimized and the resulting plants were examined using genetic markers and the appearance of each plant was evaluated. A subset of the newly created plants displayed a difference as compared to the mother plant at a marker locus. Furthermore, variation among anthocyanin pigmentation was noted among some of the newly created plants. Thus tissue culture is a viable alternative to the propagation of guava but variation can be introduced.
Technical Abstract: Micropropagation of Psidium guajava L. (guava) is a viable alternative to currently adopted techniques for large-scale plant propagation of commercial cultivars. Assessment of clonal fidelity in micropropagated plants is the first step towards ensuring genetic uniformity in mass production of planting material. In the present study, plants of guava cultivar Lucknow 49 were regenerated by micropropagation and tested for genetic fidelity by comparing them to the mother plant from which explant material was obtained. Efficient rooting of in vitro proliferated shoots was obtained by culture on ½ strength MS medium supplemented with either 9.8 µM indole butyric acid (IBA) or 10.1 µM indole acetic acid (IAA). Leaf samples of 31 regenerated plants were compared to the mother plant using 17 simple sequence repeat (SSR) markers. While 16 SSRs detected a single allele, locus mPgCIR07 detected genetic variation, where six micropropagated plants were 1 bp smaller (152bp) than the parental genotype (153 bp). Differences in leaf tissues for anthocyanin pigmentation were also noted among micropropagated plants. Results of the study indicated efficient rooting of Lucknow-49 cultivar for rapid propagation of planting material and revealed that micropropagated plants were identical for most loci examined, although phenotypic variation was introduced.