THE ESTABLISHMENT AND REGENERATION OF A RANGE OF CUPHEA GERMPLASM IN-VITRO

The range of Cuphea species previously investigated in vitro has been extended, and the potential of a number of species for uptake into gen e transfer systems evaluated. Eight species were successfully establis hed in culture and assessments of relative subculturing potential rate s after 4 weeks varied from 10.3 per initial shoot in C. wrightii to 2 .3 in C. leptopoda. In tissue regeneration studies, callus formation w as rapid and efficient from seven of the eight lines investigated and the species C, lutea, C. lanceolata, C. leptopoda, C. paucipetala and C, laminuligera (in addition to the previously reported C. wrightii) r egenerated shoots in vitro from leaf explants after three to six weeks culture on a medium containing 8.8 mu M BA, in a two-stage protocol. A high incidence of in vitro flowering was also recorded in C. lutea, C. leptopoda and C. paucipetala. Though initial growth rates were comp arable, it was found that extended culture on a matrix of Phytagel rat her than agar was detrimental to subsequent shoot development.