MORPHO-ANATOMICAL CHARACTERIZATION AND GENETIC ANALYSIS IN KENAF (Hibiscus cannabinus L.)

Abstract

The experimentations were carried out with forty kenaf genotypes to characterize morpho anatomically, to investigate genetic diversity, combining ability, heterosis and nature of gene actions for different yield contributing characters during 2016 to 2019. Three experiments were conducted at the Jute Agriculture Experimentation Station, Manikganj, Central Station, Dhaka and one laboratory experiment was carried out at Genetic Resources and Seed Division and Textile Physics Department of of BJRI. Data were recorded on morpholo-anatomical traits. Principal component analysis showed that the first five axes accounted for 99.75% of total variation among the genotypes. The highest intra cluster distance was found in cluster VI and the lowest was in cluster I. Among the six clusters, results on intra and inter-cluster distances showed that the genotypes were highly divergent from each other. Comparison between two clustering indicated that grouping of genotypes based on morphological traits slightly differed with the grouping. The genotypes G1 (HC-95), G7 (Acc.1983), G27 (4627), G10 (Acc. 4658), G24 (Acc.4444) and G36 (Acc.4997) were chosen from different clusters as parent for hybridization. The ANOVA showed that variances for general combining ability (GCA) and specific combining ability (SCA) were highly significant for all the traits, suggesting the presence of both additive and non-additive gene actions for the inheritance of the concerned characters. The highest GCA variance was found in days to 1st flowering, node number and 1000 seeds weight considerably higher than that of SCA variance, indicating the importance or presence of additive gene action for these traits. For all other characters non-additive genetic effects were more important for their inheritance. Ranking of parents on GCA performance indicated that P4 (Acc. 4658), was the best general combiner for earliness (-12.68) and number of fruits/plant (0.72) followed by P5 and P2, respectively. For fibre yield and yield attributes, P6 (3.88) was the best general combiner followed by P5 (1.90) and P1 (0.50). On SCA performance, the hybrid P2 x P5 was the best for fibre related traits except green bark thickness and followed by P1 x P6, P4 x P6 and P4 x P5. The hybrid P1 x P5 showed the maximum SCA for earliness, while the best specific hybrid for smaller seed size was P5 x P6. Considering combining ability, the hybrids P2 x P5, P1 x P6 and P3 x P6 found promising for their higher fibre yield potentiality. Contrary, the hybrids P1 x P5, P5 x P6 and P4 x P6 (0.78) found promising for earliness, smaller seed size and fibre strength, respectively. In F1, F2 and backcross generations revealed that both additive and non-additive gene actions were important in the expression of morphological traits, however, a predominance of additive gene effects. The extent and direction of heterosis in F1 varied greatly for different characters and for different hybrids. Vr-Wr graph suggested that partial dominance and/or overdominance gene actions were involved for all the characters in F1, F2 and backcrosses. The narrow sense heritability (h2 n) from genetic components was very high for number of trapezoid (0.42) and followed by bark thickness (0.30) and fibre whiteness (0.26) for anatomical study. Considering the bark thickness, the ratio of fibre length and breadth, and fiber strength; the highest heterosis were manifested in P2×P4 (23.16%), P1 × P2 (32.71 %), and P1 × P2 (22.03 %), over better parent and check varieties.