Plant Regeneration from Callus Cultures of Maclura tinctoria, an Endangered Woody Species

Some native species produce seeds with a low frequency of germination accompanied with a period of dormancy. These features make it difficult to produce new phenotypes through sexual propagation. Maclura tinctoria has been considered an endangered species due to extensive use of its wood and low frequency of seed germination. The objective of the present study is to establish an in vitro propagation system for this species. Organogenic friable callus formation from nodal segments has been obtained using woody plant medium (WPM) supplemented with$10.74 \mu M$1-naphthaleneacetic acid$(NAA) + 4.43 \mu M$6-benzylaminopurine (BA). Results indicate that the highest frequency of shoot formation is observed when WPM supplemented with$4.03 \mu M$NAA + 4.43 BA is used. For root formation, the use of WPM medium (pH adjusted to 7.0) supplemented with$23.62 \mu M$indole-3-butyric acid (IBA) and$4.7 g l^{-1}$activated charcoal is recommended. For acclimatization, subjecting rooted plantlets to 70%, 50%, and 30% mesh screen, each successively for a period of 7 d, has resulted in 97% plantlet survival.