MORPHO-ANATOMICAL CHARACTERIZATION AND GENETIC ANALYSIS IN TOSSA JUTE (Corchorus olitorius L.)

Abstract

The investigations were carried out with fifty-eight olitorius genotypes to characterize, genetic variation, diversity, assess combining ability, estimate heterosis and nature of gene actions for different characters during March, 2016 to December 2019. Out of four, three field experiments were conducted at the JAES, Manikganj, BJRI and one laboratory experiment was conducted at GRSD laboratory of BJRI. Data were recorded on morpho-anatomical traits. Principal component analysis on correlation matrix of morphological traits showed the first three axes accounted for 98.65% of total variation among the genotypes. Fifty-eight germplasm were grouped into five clusters. The highest intra cluster distance was found in cluster III and the lowest was in cluster IV. Among the five clusters, the highest inter cluster distance was observed between II and III and the lowest between cluster I and V. Distribution pattern indicated that genotypes collected from the different location were grouped into different clusters. Intra and inter-cluster distances showed the genotypes were highly divergent from each other. Genotypes G 15 (A1354), G 25

(A-1773), G 30 (A-3705), G 32 (A-3988), G 38 (A-4481) and G 58 (O-9897) were chosen from different clusters for hybridization and crossed in a half diallel method for heterosis and combining ability analysis. The ANOVA of combining ability analysis showed highly significant for all the characters which suggested the presence of both additive and non-additive gene action for inheritance. The GCA effects revealed that the parents P 2 and P 6 showed the best general combiner followed by P 2 . The SCA performance revealed that the hybrids P 3 × P 5, P 1 × P 6 , P 1 ×P 5 and P 2 ×P 6 would be the best consideration in fibre yield and the hybrids P 1 ×P 3 , P 4 × P 5 , P 3 × P 6 and P 2 × P 5 would be the best choice for seed production. Genetic analysis in F 1 , F 2 and backcross populations revealed that both additive and non-additive genetic effects were important for different characters. Extent and direction of heterosis in F 1 varied greatly for different characters. Vr-Wr graph suggested that partial dominance and/or over dominance gene actions were involved for all the characters in F 1 , F 2 and backcrosses. Considering heterosis, the hybrids P 2

× P 6 , P 3 × P 5 and P 5 ×P 6 deserve attention for their heterotic responses. The narrow sense heritability was estimated very high for seeds/fruit (0.505) in F 1 , F 2 (0.499)

and P 3 and backcross (0.467, 0.499) generations which indicated that effectiveness for improvement by selection in that characters. In anatomical study heritability in narrow sense was high for bark thickness (0.4921) followed by length breadth ratio and fibre strength. Considering heterosis, combining ability, genetic analysis and anatomical study, the hybrids P 2 × P 6 and P 3 ×P 5 found superior for fibre yield, quality and seed related characteristics. These hybrids could be used for the development of tossa jute varieties.