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

General and specifi c 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 fl ower Suhum - S1, white fl ower 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. Th e trial was set up in 2007 at the Experimental fi eld of Tobacco Institute-Prilep in randomized block design with four replications. For the analysis of the combining abilities, Griffi ng’s Method 2 Model 1 was used. Th e 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. Th e three varieties in these two combinations showed low GCA for the same character. Th e only combination with high SCA for leaf number per stalk was S1 x S2 (hybrid created from two lines of a same variety, diff ering only by their fl owers 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.