ABSTRACT

This study examined the effects of different doses of x-ray on seeds germination of three selected indigenous forest fruit trees. Dosimetry test was carried out for the three plant species seeds from which two doses with positive effects on root length and shoot height were picked for the study in each plant species. Breadfruit seeds were exposed to 6 MGy and 8 MGy. Locust bean seeds were exposed to 2 MGy and 4 MGy, African oil bean seeds were exposed to 4 MGy and 8 MGy before sowing. Germination percentage and rate ofthe selected plant species were investigated. The experimental design was arranged in a completely randomized design. Growth parameters were measured at 2 weeks intervals for 12 weeks. Genomic DNA extraction and analysis were carried out using RAPD marker with gel electrophoresis for the primers. At the end of 12 weeks, biomass in form of dry weight was assessed. The result of DNA analysis showed polymorphism in all the primers. T. africana control and treated samples (6 MGy and 8 MGy) had alleles at different position in primer OP-T06. Two alleles common to treated samples in primer OP-T20 but absent in control. Four alleles common to treated sample of T. africana in primer OPT-07 which were absent in control. Control had one alleles in primer OPT-07 but were not found in treated samples. For P. biglobosa sample, two alleles in primer OP-T06 were found at position 600 bp and 550 bp. In primer OP-T20 and OPT-07 treated sample 4 MGy had two bands with 350 bp P. macrophylla (8 MGy) had three bands in primer OP-T06. P. macrophylla 4mgy had four bands in primer OP-T06. One allele common to 4 MGy in primer OPT-07. Three alleles also common to 4 MGy in primer OPH-05. Three allele with 1000 bp, 800 bp and 350 bp common with P. macrophylla 4 MGy and 8 MGy in primer OPH-05. The analysis of variance calculated for T. africana seedling parameters: height, stem diameter and leaf production were significant. The analysis of variance calculated for leaf area was not significant (P < 0.05). For the species P. biglobosa the ANOVA result showed significant difference in height, stem diameter, leaf area and leaf production (P < 0.05). In species P. macrophylla ANOVA at (P < 0.05) showed significant difference in height growth, diameter, leaf area, and leaf production. The result of biomass (dry weight) analysis in T. africana gave highest mean weight of 4.360 g and there was no significant effect (P < 0.05). For P. biglobosa, the highest mean (3.4750 g) weight was recorded in treated sample 2 MGy ANOVA showed significant effect. For the species P. macrophylla the highest mean dry weight 4.360 g was recorded in control sample and there was no significant effect (P < 0.05). The results showed that x-ray had effect on the genome of the selected indigenous forest trees.