An experiment was conducted to examine the magnitude of genetic diversity and characters contributing to genetic diversity among 81 tossa jute genotypes. Cluster analysis based on Euclidean squared distances and ward's method, the genotypes were grouped into ten distinct clusters. Analysis reveals that stick weight contributes maximum to the phenotypic diversity (65.52%) followed by green weight (13.64%) and fibre yield (10.10%). Among the clusters Cluster IX recorded highest mean fibre yield (19.91g) followed by Cluster VII (18.94g) and these clusters also recorded high mean values for plant height, basal diameter, green weight and stick weight. The highest intercluster distance was 186.80 (between clusters II and X) followed by 161.26 (between clusters IV and X), indicating the wide genetic diversity among these clusters. The highest intra-cluster distance was observed in cluster II (20.34) and the lowest in cluster X (3.17). The average inter-cluster distances were higher than the average intra-cluster distances, which shows the presence of wide genetic diversity among the genotypes of different clusters than those of the same cluster. The first two principal components, whose Eigen values are greater than one, accounted for 74% of the total variation among the five characters. The information obtained from diversity analysis is useful in planning further breeding programme for tossa jute improvement.

Estimates of gene effects through joint scaling test of three and six parameter and sequential fit model in five crosses for eleven characters were investigated. It was noticed that simple additive dominance model exhibited lack of good fit for all the traits. So, sequential fit model was searched after eliminating the non-significant parameters of six parameter model. Five parameter sequential fit model was observed for number of primaries per plant (cross 1), number of seeds per capsule (cross 4), oil content (cross 2 and 3), seed yield per plant (cross 1) and chlorophyll content (cross 3). Best fit four parameter sequential model was observed for number of primaries per plant (cross 2) and 1000 seed weight (cross 1). Higher order interactions epistasis or linkage were observed for days to 50 per cent flowering (cross 1, 2, 3, 4, and 5), days to maturity (cross 1, 2, 3, and 4), plant height (cross 3, 4, and 5), number of effective primaries per plant (cross 3, 4, and 5), number of effective capsules per plant (cross 2, 3, 4, and 5), number of seeds per capsule (cross 1, 2, 3, and 5), 1000 seed weight (cross 4 and 5), seed yield per plant (cross 4 and 5), oil content (cross 1, 4, and 5) and chlorophyll content (cross 1, 2, 4, and 5). Differential model schemes for same trait in different crosses were noticed in the present investigation. It was due to different parents involved with variable gene frequency with opposing and reinforcing genetic effects. The magnitude of [d] was relatively small to that of other genetic effects. This indicated that, additive genes are playing a minor role in the inheritance of these traits.

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