Improvement of genetic variability in seedlings of Spathoglottis plicata orchids through X-ray irradiation

Abstract

Abstract. Aloysius S, Purwantoro A, Dewi K, Semiarti E. 2017. Improvement of genetic variability in seedlings of Spathoglottis plicata orchids through . Developing genetic variability of orchids via mutation is promising for orchid breeding. The objective of this research was to improve genetic variation of Spathoglottis plicata orchids through X-rayirradiation of the orchid seeds. The method involved X-ray irradiation of one month old mature orchid seeds at doses of 0, 6, 12, 18, and 24 rad. The X-ray irradiated seeds were sown on a half strength of MS medium and grown into protocorms (developing orchid embryo). Eight weeks-old protocorms were subcultured onto NP-SIM medium. Five months-old seedlings were then subcultured again into a new flask and morphological observations were recorded. Genetic variability detection was conducted using PCR RAPD based on nine primers, i.e. OPA1, OPA2, OPA11, OPA12, OPA14, OPB1, OPB4, OPD12, OPD14. The data was analyzed using GenAlex 6.1 software to obtain the genetic distance. Moreover, NTSys ver.2 was used to analyze the data for clustering and constructing a dendrogram based on Neighbour Joining model. The result showed that X-ray irradiation with doses of 12-18 rad was able to stimulate morphological variation of seedlings, especially characters of leaf, root and shoot. Interestingly, we found 2 in vitro early flowering plants among one years old X-ray irradiated plants, indicated that somehow X-ray mutation affect flowering time in orchid. Based on the dendrogram of genetic distance that the group of mutants was farther than the WT group and the percentage of polymorphism was bigger than that of wild type group, it is concluded that 12-18 rad doses of X-ray irradiation can be used for induction of genetic variability in Spathoglottis orchid.Keywords: Genetic variability, seed, seedling phenotype, Spathoglottis plicata, X-ray Abbreviations: BAP = benzylaminopurine; NAA = naphthaleneacetic acid; 2iP = 2 = isopentenyl adenine; NP = new phalaenopsis; SIM = shoot induction medium

Genetic Variability Analysis of Terrestrial Spathoglottis plicata Orchid Variants Based on RAPD Marker

“…The research was molecular explorative observation used 17 plants of S. plicata variant resulted from in vitro seed culture that have survived by previous researchers [8]. Sample consist of 6 S. plicata wild type variant and 11 mutant variant.…”

“…These variations can occur due to recombination of genes and or mutations due to the induced mutagenesis. Genetic mutations have been shown to cause changes in morphological structure in the seeds of S. plicata mutants [8]. Mutations do not always have a significant impact on changes in plant phenotypes.…”

Radiosensitivitas dan Pertumbuhan In Vitro Protocorm Anggrek ‘Tien Soeharto’ (Cymbidium hartinahianum J.B. Comber & R.E. Nasution)

“…Dosis iradiasi hingga level Suwarno et al (2013), semakin tinggi dosis iradiasi maka kemampuan setiap biakan untuk membentuk daun akan semakin rendah. Sementara itu dari hasil penelitian Aloysius et al (2017) dinyatakan bahwa, iradiasi sinar gamma pada Spathoglottis plicata dapat menyebabkan kegagalan pembelahan sel dan pertumbuhan primordia daun hanya melalui pemanjangan sel, tanpa adanya pembelahan sel maka pertumbuhan daun menjadi abnormal sehingga daun menjadi kerdil dan batang juga memendek. Pada C. hartinahianum di dalam penelitian ini, morfogenesis daun mulai terhambat pada dosis iradiasi 10 Gy di ruang kultur 16-18 ᵒC dan 20 Gy di ruang kultur B 22-27 ᵒC.…”

Phenotypic variation and genetic alteration of Spathoglottis plicata resulted from in vitro cultured seed irradiated with X-Ray

“…The POH1 or its homologous genes were members of Knox gene clusters (knotted-like orchid homeobox) which was a key gene in the shoot morphogenesis. From the results of PCR-RAPD, S. plicata seedlings experiencing prominent morphological changes show an increase in DNA polymorphism (Aloysius et al 2017). Whether the orchids S. plicata surviving in experimental gardens also undergo genetic changes especially in homologous gene POH1, is an interesting thing to be studied.…”