Abstract
Three leaf characters, i.e. the mid-rib praportion, the leaf shape and the leaf size, of to'oacco plant were genetically investigated. Statistcally significant varietal differences were found in the mid-rib proportion of the fresh leaves as well as in that of the dry ones among twenty-four varieties and three F1 hybrids. The same was also the case in the leaf shape and the leaf size. Phenotypic and genotypic correlation coefiicients were calculated between any two of these characters. The correlation between the mid-rib proportian of fresh leaf and that of dry leaf was exceedingly high. Correlation between the mib-rib proportion, and the leaf shape frcurl three different sources, including variety trials, the F2, and F3 populations was always high in the negative direction. Variances of the mid-rib protion and the leaf shape were partitioned into their D, H and E components according to MATHER'S method. On the basis of these partitioning, heritability and the number of- effective factors were estimated.
