STUDIES ON THE RELATIONSHIP BETWEEN PLOIDY LEVEL, MORPHOLOGY, THE CONCENTRATION OF SOME PHYTOHORMONES AND THE NICOTINE CONCENTRATION OF HAPLOID AND DOUBLED HAPLOID TOBACCO (NICOTIANA-TABACUM-L) AND NICA PLANTS

As compared to doubled haploid plants of the same origin, haploid toba cco plants are characterized by narrow leaves and in these leaves the endogenous concentration of gibberellins was considerably higher than in doubled haploids. This higher GA activity is almost entirely due to elevated levels of polar gibberellins. The same leaf shape as in hapl oids could be induced by GA(3) sprays to doubled haploids. A similar l eaf shape was also observed on tissue culture derived so called NICA p lants displaying the morphology of tobacco plants as described by Dudi ts et al. (1987) from whom the plant material was obtained as a gift. Here, in the leaves of a special strain with narrow lamina again a muc h higher gibberellin activity was detected than in the leaves of plant s of the original tobacco strain. Histochemical determination of the r elative DNA content indicated that leaves of NICA were chimaeras conta ining 1C cells besides cells with higher C values. Obviously, haploidy is somehow related to the endogenous gibberellin activity in tobacco plant material with consequences on the morphological appearance of In plants. Comparing some haploid and doubled haploid strains in tissue culture and pot and field experiments in several years apparently the genotype of the plant material is more significant for nicotine concen tration than the ploidy level.