SHOOT REGENERATION AND PLOIDY LEVEL OF PLANTS OBTAINED FROM STEM PITH TISSUE IN VITRO CULTURES OF TOBACCO (NICOTIANA TABACUM L.)– Anna Trojak-Goluch
The plant material were haploids obtained from anther in vitro cultures of two-way F1 hybrids (BPA × WGL3, WGL3 × BPA, WABPA3 × WGL3, WGL3 × WABPA3, WGL3 × PW834, PW 834 × WGL3), breeding lines (WGL3 and PW834) and cultivar Wiślica, previously obtained as part of a breeding program involving combining resistance to fungal and viral diseases in the tobacco genome. Stem pith fragments of haploids were cultured on Lloyd medium containing 2 mg/l IAA i 2 mg/l kinetin. The assessment of shoots regeneration of tobacco as well as the degree of plant ploidy were evaluated using flow cytometer. The efficiencyof regeneration, expressed as the number of shoots per explant, varied and depended on the genetic origin of haploids (F1 hybrid, breeding line, cultivar). The lowest number of regenerated shoots (2.8/explant) were obtained from the breeding line PW834. Poor organogenetic abilities were probably due to the presence of genetic material from Nicotiana alata in the PW834 genome. The highest number of regenerated shoots (13.8 i 10.2/explant) was obtained from haploids of F1 hybrids WGL3 × BPA and cultivar Wiślica, respectively. Flow cytometry analysis of regenerants revealed that, depending on the tobacco form, 59.84 to 89.39% of the individuals remained haploids, whereas from 10.61 to 32.99% of the regenerants were doubled haploids. There was also a small number of polyploids. Hybrids WGL3 × WABPA3 proved to be the best donor of explants for in vitro induction of doubled haploids and polyploids.
Keywords: haploid, doubled haploid, polyploid, organogenesis, regeneration efficiency