Heterosis and combining ability of certain chemical traits in burley tobacco

Four parent burley tobacco cultivars and their F-1, F-2, Bc(1) and Bc(2) pr ogenies were included in a four-year trial. The aim of these studies was to estimate the manner of inheritance of chemical traits (nicotine, proteins, total nitrogen and ash content). Medium to high broad-sense heritability, but also very low narrow-sense heritability, were estimated for most of the traits tested. Negative heterosis was estimated relative to better parent, and in some cases also to mid-parent. Negative inbreeding was recorded for nicotine and total nitrogen, and positive for ash content. Significant GCA was estimated for all the traits rested, while significant SCA was recorde d in one or two years, however not for all traits. Genotype Poseydon was th e best in GCA, and Hy 71 x TN 86, Hy 71 x BL1 and Poseydon x BL1 were the b est in SCA.