Dendrobium is the second largest genus in the Orchidaceae family. Dendrobium section Spatulata is widely cultivated in Indonesia due to its ease of cultivation, high economic value and adaptability, and extended flower shelf life. In this study, we have conducted a breeding program for developing new cultivar of Dendrobium section Spatulata through interspecific hybridization. This study is aimed to investigate the genetic variation and genomic constitution of the eight hybrids and their corresponding parental lines resulted from interspecific hybridization using SRAP markers. Dendrobium section Spatulata hybrids produced by interspecific hybridization are genuine hybrids with substantial genetic variability based on flower morphology, including labellum shapes and color intensities, as well as curly horn shapes and color intensities. The SRAP marker, which was utilized to genotype the hybrid and parental lines, exhibited a significant degree of polymorphism, and may be used to distinguish each accession. The UPGMA dendrogram and PCoA biplot showed that all the hybrids were grouped with their corresponding parental lines based on their genetic background and genomic constitution. These findings are critical for genetic improvement of the Spatulata orchid to develop novel varieties.

Abstract. Nurmansyah, Setyadi AH, Fatumi NC, Fatmawati Y, Wulandari RA, Purwantoro A. 2021. Genetic variation of doubled haploids derived from anther culture of M1 red rice plants. Biodiversitas 22: 4923-4929. The doubled haploid (DH) technology when integrated with induced mutation could accelerate development of local rice cultivars with several desirable traits. Anthers from the first generation of mutant (M1) plants were utilized for DH production. However, the effectiveness of inducing and fixing mutation requires detailed evaluation with the help of molecular techniques for its accuracy and reliability than that of morphological or biochemical assessments. The objective of this research was to develop and detect genetic variation of DH plants derived from anther culture of M1 plants. Seeds of local red rice cultivar, Cempo Abang, were treated with four gamma-ray doses (0, 100, 200, 300 Gy) and planted to produce the M1 plants. Panicles at the booting stage of the M1 plants were collected and used as donor anthers. The present study suggested that gamma irradiation treatments indirectly could increase callus formation. However, it also reduced the number of callus producing plantlets due to higher frequency of brown calli. Eleven spontaneous DH plants obtained in the study along with parental plants were assessed to determine the occurrence of genetic variation using six RAPD primers. The RAPD primers generated 51 bands, of which 34 alleles or 66.7% were polymorphic with an average of 5.6 polymorphic alleles per primer. The genetic similarity among parent and 11 DH lines based on Jaccard’s similarity index ranged from 0.622 to 0.902. The DNA polymorphism among the DH plants demonstrated the effect of gamma irradiation to create genetic variation. Therefore, this method could be used as an alternative for rice breeding programs especially to develop preferred traits in the local rice cultivars.