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

Abstract

As compared to doubled haploid plants of the same origin, haploid tobacco 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 haploids could be induced by GA₃ sprays to doubled haploids. A similar leaf shape was also observed on tissue culture derived so called NICA plants displaying the morphology of tobacco plants as described by Dudits 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 much higher gibberellin activity was detected than in the leaves of plants of the original tobacco strain. Histochemical determination of the relative DNA content indicated that leaves of NICA were chimaeras containing 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 1n 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 concentration than the ploidy level.