Cytogenetic studies in “X-7”, a new line of Papaver bracteatum Lindl. with increased thebaine content

Abstract

Papaver bracteatum Lindl. is of substantial medical and pharmaceutical interest as material for commercial production of codeine. During various experiments, some involvingcolchicine treatment of seeds, a diploid plant (called “X-7”) developed. This plant had a substantial increase in the amounts of thebaine, the main alkaloid produced in the capsules. By cloning this plant, a new series of bracteaturn plants were obtained, and the thebaine content of the new individuals vaned markedly from ca 3 % to about 17 % against normal variation from 1 70 to 3 70. Subsequent cytological analyses revealed the X-7 plants to be diploid (2n=14). Their karyotype may contain minor structural differences from the mother line, but these were difficult to characterize. Marked differences of meiotic behaviour occurred. The “X-7” line appears to have arisen through diploidization and chromosomal rearrangements from polyploid tissue.