The efficient induction of tetraploid plants via adventitious shoots in Antirrhinum majus L. by in vitro seed treatment with amiprophos-methyl

Abstract

Tetraploid plants of Antirrhinum majus L. were obtained from the seeds of the F1 variety ‘Maryland True Pink’ by amiprophos-methyl (APM) treatment and subsequent in vitro culture. Seeds were treated with 0, 10 and 20 mgl−1 APM for 1, 3, or 7 d (day) with or without osmopriming. Overall, the seedlings established from the seeds treated with 10 or 20 mgl−1 APM for 3–7 d exhibited malformation with rudimentary roots and swollen hypocotyls that eventually produced adventitious shoots. The highest adventitious shoot formation frequency reached 71.6% in non-primed seeds treated with 10 mgl−1 APM for 7 d; this decreased to 54.4% in osmoprimed seeds that received the same APM treatment. The plantlets from the adventitious shoots were identified as tetraploids at frequencies of 51.4% and 90.4%, respectively. Tetraploid frequency increased with higher concentration and/or longer duration of APM treatment and ranged from 0 to 65.9% in the non-primed seeds and 10.3% to 100% in the osmoprimed seeds. Osmopriming of seeds accelerated the induction of tetraploids by APM treatment at the same concentration and duration by 10.3–39.0%, except in the case of treatment with 20 mgl−1 APM for 3 d treatment. In the osmoprimed seeds treated with 20 mgl−1 APM for 7 d, all the plantlets from the adventitious shoots were revealed to be tetraploids. This study revealed that APM has dual effects, namely the inhibitory effect on the growth of seedlings and the stimulatory effect on the induction of adventitious shoots on the hypocotyl of seedlings. APM induced adventitious shoots on the hypocotyl of seedling by seed treatment and the induced-adventitious shoots were identified to be tetraploids. Osmopriming accelerated the frequency of tetraploid induction.