Plant regeneration and clonal fidelity assessment of subendemic species Iris illyrica Tomm. originated from Croatia

Abstract

The present study was undertaken to evaluate efficiency of callogenesis and regeneration by somatic embryogenesis of the subendemic Iris species Iris illyrica from Croatia and to select highly regenerative donor plants/genotypes. Leaf base segments were used as explants. Callogenesis and somatic embryogenesis were induced on MS media supplemented with: (1) 4.52 M 2,4-dichlorophenoxyacetic acid (2,4-D) + 4.83 M 1-naphthaleneacetic acid (NAA) + 0.46 M kinetin (Kin); (2) 4.52 M 2,4-D + 4.6 M Kin; (3) 13.4 M NAA + 2.3 M Kin. Transfer of embryogenic calli onto hormone-free medium enabled the development of mature somatic embryos. Frequency of callogenesis was influenced by the donor plant. Among 15 donor plants tested, 3 of them exhibited high regeneration capability and produced 87 regenerants. Seven morphological traits were observed in order to assess phenotypic variability of flowering regenerants. Regenerants with higher values of fall and standard width and length show potential for further breeding of new varieties of Illyrian iris. Flowering and non-flowering regenerants had the same ploidy level as donor plants. Also, the nuclear DNA content (2C = 12.936 ± 0.038 pg) of this species was estimated for the first time using flow cytometry.Ovo istraživanje provedeno je s ciljem procjene uspješnosti kalogeneze i regeneracije somatskom embriogenezom hrvatske subendemske vrste Iris illyrica, te odabira regenerabilnih donorskih biljaka/genotipova. Kao eksplantati korištene su baze listova. Kalogeneza i somatska embriogeneza inducirane su na MS mediju uz dodatak (1) 4,52 M 2,4-diklorofenoksioctene kiseline (2,4-D) + 4,83 M α-naftalenoctene kiseline (NAA) + 0,46 M kinetina (Kin); (2) 4,52 M 2,4-D + 4,6 M Kin i (3) 13,4 M NAA + 2,3 M Kin. Prijenosom embriogenih kalusa na medij bez dodatka regulatora rasta omogućen je razvoj zrelih somatskih embrija. Na uspješnost kalogeneze značajno su utjecale donorske biljke. Među 15 testiranih donorskih biljaka, tri su pokazale veliku sposobnost regeneracije i proizvele 87 regeneranata. U svrhu procjene fenotipske varijabilnosti cvatućih regeneranata, mjereno je sedam morfoloških karakteristika. Regeneranti s utvrđenom većom širinom i dužinom donjeg i gornjeg lista perigona u odnosu na matične biljke predstavljaju potencijalno vrijedan genetski materijal za selekciju novih kultivara Ilirske perunike za hortikulturnu primjenu. Cvatući i necvatući regeneranti imali su jednak stupanj ploidnosti kao i donorske biljke. Također, po prvi puta je procijenjen sadržaj jezgrine DNA (2C = 12,936 ± 0,038 pg) ove vrste upotrebom protočne citometrije.