Long term plant regeneratin from callus cultures of haploid wheat

A one-step method to rescue immature embryos of eastern cottonwood (Populus deltoides Bartr.) is described. Plantlets developed from 83% of 25-day-old embryos grown in shaken culture on Murashige and Skoog (MS) liquid medium with 2.2 m indole-3-acetic acid (IAA) and from 86% of embryos not supplemented with IAA. In contrast, when the MS medium was solidified with 0.8% agar, plantlets developed from 25% of 25-day-old embryos cultured on medium supplemented with IAA and from 28% of embryos in medium not supplemented with IAA. Eighty eight percent of all plantlets survived a gradual acclimitization to peat plugs in a greenhouse. The one-step liquid-culture method is an effective means of rescuing immature embryos by ovule culture from excised artificially-pollinated female branches in our cottonwood breeding program.