ABSTRACT

This study examined the effects of different concentrations of EMS on seed germination,growth and yield of three varieties of Capsicum chinense. The accessions were collected from different localities (oriugba, ubani market and isi gate) in Abia State. The study adopted a Randomized Complete Block Design (RCBD) with three replicates. The three varieties of Capsicum chinense were exposed to different EMS concentrations (0.1%, 0.3%, 0.5%, 0.7% and 0.9% v/v) and 5hrs exposure time, non treated seed were used as a comparative control. After treatment for 5hrs, the seed were grown in planting bags and were watered every day. The germination percentage were recorded, to determine the effects of EMS dose for the three varieties by subjecting the data  collected to linear regression on the basis of their( growth parameters) plant height , number of leaves, number of branches, stem girth,  leaf area were taken at every three weeks interval (3,6,and 9 Weeks after transplant) and yield parameters ( numbers of days to first fruits flowering, number of fruit per plant, number of seeds and weight of fresh fruit) was also recorded. Data were subjected to Analysis of Variance (ANOVA) and Least significant difference (LSD) was obtained at P<0.05. The results obtained from germination percentage showed that the germination of seeds was highest at the control (0.0%) and reduced among the treated plants. This reduction was observed to be concentration dependent. The LD₅₀ values of 0.8%, 0.5% and 0.5% (v/v) EMS dosage was identified as an optimal doses for the three varieties of pepper plants. The results of different EMS concentrations on growth parameters of Capsicum chinense at 3,6 and 9 weeks after transplant indicated that there were significant difference (P<0.05) between the means of the treated plant when compared with control plants. Data obtained showed that treatment range from 0.1% to 0.5% EMS improved the genetic variability of the three varieties of pepper plants at morphological levels. The yield performances on the pepper varieties significantly improved the yield characters induced by the mutagen. The results of the analysis of variance showed that the plants treated with 0.1% EMS and 0.3% EMS enhanced the yield of this species. Molecular analysis was carried out using ISSR marker (Intersimple sequence repeat). Ten ISSR markers and rbcL primer was combined for the sequencing analysis and showed variability among the treated plants compared with the control. The ten ISSR marker detected 30 polymorphic alleles.  The number of alleles for the ISSR loci ranged between 2, 3 and 4, with an average of 2.7 allele’s locus -1.The polymorphic information content were characterized in terms of their similarity to the records deposited in a Gene bank database. The types of sequences present in the polymorphic bands reflected the arrangements of the pepper varieties genome. Shifting the seasonal timing of reproduction is a major goal of plant breeding efforts to produce novel varieties that are better adapted to local environments. Hence  lower EMS concentration   positively improved the growth and yield characters of this study.