Abstract
Seven different experiments were conducted to assess morpho-molecular variation among 51 Kenaf genotypes and to develop a reproducible protocol for in vitro regeneration. Morpho-physiological, yield and yield contributing characters significantly varied among the genotypes where the highest plant height, base diameter, node plant1, green weight with leaves plant-1, dry stick weight and fibre yield plant1 were found in HC-2. Green weight with leaves showed the highest variance (13569.98 and 13713.22) in both genotypic and phenotypic levels, respectively while highest heritability (99.53%) was observed in fruit number plant1. The highest GA was found in green weight with leaves (238.71) while fruits plant1 showed the highest GCV (47.17%) and PCV (47.28%). Positive significant correlation was found in fibre yield at both genotypic and phenotypic levels while fibre yield had highly positive correlation with green weight with leaves (0.828** and 0.827**) at genotypic and phenotypic levels. The highest number of populations (12 genotypes) was in cluster III and V, while the highest inter-cluster or genotypic distances (3000.90 or 54.78) was observed between cluster II and IV. Relatively high genetic distance was observed between cluster II and IV while cluster IV showed the higher (2151.05 or 46.38) intra-cluster distance. In PCA, three components had the eigenvalues greater than 1 and accounted for 66.36% of the total variation. Out of 16 RAPD markers, three markers produced comparatively higher number of high intensity bands with minimal smearing, good technical resolution and sufficient variation while OPAB-02 generated the highest number of bands (12) among the three primers. The highest value of genetic diversity 0.4998 and Shannon's information index 0.6930 were found in locus OPAB02-12, S1063-11 and S1265-4 RAPD primers while the highest values of gene frequency (0.9412) was found in OPAB02- 41863 and higher genetic distance (1.7047) was observed between accession 1585 and accession 5073. Result showed that a total of 26 alleles were detected by three SSR primers (MJM606, MJM618 and MTIC3) among the 51 Kenaf germplasms while average number of allele per locus was 8.66 with a range of 7 (MTIC3) to 11 (MJM606) while MJM618 detected the highest number of rare alleles (3). The highest level of gene diversity value (0.89) was observed in loci MJM606 with a mean diversity of 0.79. PIC values also showed a significant positive correlation with the number of alleles and allele size while the frequency of the most common allele at each locus ranged from 17.65% (MJM606) to 43.14% (MJM618) with a mean frequency of 33.99. The size of the different major alleles at different loci ranged from 76 bp (MJM618) to 228 bp (MTIC3) while higher genetic distance (1.00) was observed between accession pair 1623 vs 1624 and some other accessions. The hypocotyls explants of HC-95 cultured in 4.0 mgl-1 BAP + 2.0 mgl-1 NAA (V2E3T15) gave significantly the highest callus formation (93.33%) and shoot regeneration (86.67%) while number of shoots callus-1 was the highest (5.667) in 2.0 mgl-1 BAP + 1.0 mgl-1 NAA treated hypocotyl s of HC-95 (V2E3T10). The highest number of shoots callus-1 (3.67) was found in hypocotyl explant of HC-95 treated with 5.0 mgl-1 TDZ + 1.0 mgl-1 2,4-D (V2E3T13) while the highest regeneration of shoot (73.33%) was recorded in cotyledon explants of HC-3 cultured in 4.0 mgl-1 TDZ + 1.0 mgl-1 2,4-D (V3E2T9). The plantlets of HC-95 were successfully established on soil mixture consisting of equal amount of sawdust and peat soil while no plantlets were established when the soil consisted only of sawdust. The regenerated plantlets of HC-95 were more suited than HC-3 and HC-2 for establishment on this mixture. From the above findigns, it could be concluded that the genotype HC-2 would be high productive while green weight with leaves and basal diameter whould be the most vital characters for enhancing the fibre yield. The variation assessed among genotypes by molecular markers could be used in future breeding program for Kenaf improvement while the in vitro regeneration protocol developed has the potential use in improvement through genetic transformation.