In plant breeding programs with vegetatively propagated plants, induced mutations with low physiological effects and strong genetic effects are important approaches for broadening the genetic variation. In the present study, intersimple sequence repeat (ISSR) assays were used to identify DNA polymorphism among the mutant varieties of Curcuma alismatifolia (Chiang Mai Red, Sweet Pink, Kimono Pink) and one hybrid (Doi Tung 554) exposed to 0-, 10-, and 20-Gy optimum doses of acute gamma irradiation. To identify DNA polymorphism among the mutants (10 and 20 Gy) and non-treated (0 Gy) samples through ISSR assay, a total of 25 random primers were screened and 14 gave reproducible polymorphic bands. The number of presumed alleles revealed by the ISSR analysis ranged from three to 19 alleles with mean values of 6.5, 7.8, and 9.2 alleles per locus for doses of 0 (control), 10, and 20 Gy, respectively. The average effective number of alleles, Nei’s gene diversity, Shannon’s information index, and polymorphic information content (PIC) were 1.41 to 1.48, 0.24 to 0.33, 0.35 to 0.45, and 0.21 to 0.25 for the three doses, respectively. Percentages of polymorphic loci for non-irradiated (0 Gy), 10 Gy, and 20 Gy individual plants were 76.4%, 83.7%, and 85.8%, respectively, with an average of 81.9%. Jaccard’s genetic similarity coefficient varied from 0.19 to 1.0 indicating the level of genetic variation among the mutants studied. In terms of variety, the range of genetic variation (0.27 to 0.4) among individuals of the Doi Tung population was more than that observed in the other three varieties. In a dendrogram constructed based on genetic similarity coefficients, the 44 C. alismatifolia individual plants fell into seven major clusters at a coefficient level of 0.35. The study revealed that DNA polymorphism detected by ISSR analysis offered a useful molecular marker for the identification of mutants in gamma radiation-treated plants. Additionally, this research demonstrated that the DNA of the hybrid (Doi Tung 554) showed a greater response in induced mutation compared with the other varieties.
Sima Taheri, Thohirah Lee Abdullah, Nur Ashikin Psyquay Abdullah and Zaiton Ahmad
Chen Xingwei, Thohirah Lee Abdullah, Sima Taheri, Nur Ashikin Psyquay Abdullah and Siti Aishah Hassan
Synsepalum dulcificum from the family Sapotaceae is known as miracle fruit and is a valuable horticultural species. All plant parts are of medicinal importance whereas the fruit known as magic berry, miracle berry, or sweet berry is consumed fresh. Surprisingly, very little is known on the species in terms of flower morphology and flower development. In this study, an observation on the flower morphology and flower development of miracle fruit has been made with the aid of microscopic techniques. Miracle fruit flower requires 100 days to develop from reproductive meristem to full anthesis. The flower development can be divided into six stages based on the size and appearance of the flower bud. The fruit with persistent style developed and ripened 90 days after anthesis. Heavy fruit drop was observed at 40–60 days after anthesis which contributed to the final fruit set of average of 5.06% per plant. Through this study, miracle fruit is strongly insect pollinated and prevents self-fertilization. A study on pollination ecology is needed to identify the pollinator for miracle fruit, as this is important in manipulating fruit loading in the future.