Investigations of Combining Abilities in Diallel Set of Varieties Belonging to Several Tobacco Types

General and specific combining abilities were investigated for the characters stalk height, leaf number, fresh mass and dry mass per stalk in four parental genotypes (Burley B-2/93, pink flower Suhum - S1, white flower Suhum - S2 and Prilep P-84) together with their six diallel F1 hybrids with the aim of improving the process of creation of new varieties. The trial was set up in 2007 at the Experimental field of Tobacco Institute-Prilep in randomized block design with four replications. For the analysis of the combining abilities, Griffing’s Method 2 Model 1 was used. The best general combiner for stalk height and fresh/dry yield mass per stalk was B-2/93, and for leaf number it was P-84. Hybrids S2 x P-84 and S1 x P-84 showed the best SCA for stalk height. The three varieties in these two combinations showed low GCA for the same character. The only combination with high SCA for leaf number per stalk was S1 x S2 (hybrid created from two lines of a same variety, differing only by their flowers color, which indicates an intravarietal hybridization, applied as a method for maintenance of varieties, in order to prevent degeneration and to increase the biological potential of the variety). Hybrids B-2/93 x S2, B-2/93 x P-84 and B-2/93 x S1 have high SCA for fresh/dry mass yield per stalk. In all three combinations, maternal variety B-2/93 was with high GCA values, and parental varieties with low GCA values