Abstract
This experiment was conducted to artificially induce loquat tetraploids by applying amiprofos-methyl (APM) and colchicine for chromosome doubling agents to diploid loquat shoot apex.
Germinated shoot tips from the seeds of the diploid loquat ‘Kusunoki’ were immersed in aqueous solutions of APM or colchicine, and one tetraploid was produced by either immersing 14 shoot tips in a 0.2% colchicine solution for 14 days, 48 shoot tips in a 2% colchicine solution for 4 days, or 30 shoot tips in a 0.005% APM solution for 14 days. Young intact on-tree shoot tips of an 11-year-old diploid loquat ‘Tomifusa’ were immersed in a 0.005% APM solution for 14 days, one tetraploid was obtained from 50 shoots treated. ‘Kusunoki’ seeds on growing young roots were planted on a culture plate containing 0.005% APM solution for 14 days, and one tetraploid was obtained from 50 seeds treated. Apical meristems removed from young intact on-tree shoots of ‘Kusunoki’ cultured on Murashige and Skoog (MS) agar medium for 14 days were treated with APM by transplanting on MS agar medium containing 0.005% APM for 7 days. By this treatment, one tetraploid was obtained from 21 meristems treated.
