Abstract:
Two different studies were carried out on six improved African lowland rice varieties, namely BW-348-1, FARO-44, FARO-57, NERICA-L-19, NERICA-L-34 and WITA-4. In the first study, the genetic diversity and phylogenetic relationship among the six rice varieties were investigated using 129 simple sequence repeats markers. The six varieties produced a total of 492 alleles and the average number of alleles per locus was 3.8. The polymorphism Information Content (PIC) values ranges from 0.0 to 0.375 and gene diversity ranges from 0.0 to 4.4. Sixty-two (62.79%) of the primers revealed at least 3 alleles while 37.21% produced monomorphic bands for the six varieties. The size of the detected alleles produced from the SSR primer sets ranged from 50bp to 400bp, showing a large difference in the number of repeats between the different alleles. The SSR base dendogram generated and the Principal Component Analysis (PCA) clustered two genotypes BW-348-1 and FARO-44 together and three genotypes FARO-57, NERICA-L-19 and WITA-4 together. Though WITA-4 branched separately from the other two, NERICA-L-34 occupied a distinct position that is different from the other genotypes.
In the second study, the six varieties were subjected to field test during which ten yield attributes were considered to evaluate their yield potentials. The experimental design adopted in this study was the randomized complete block design (RCBD) with three replications. Data collected were subjected to analysis of variance (ANOVA) and
means separated using Duncan’s multiple range test (DMRT). There were no significant differences among the six varieties with respect to yield but WITA-4 showed the highest mean value for grain yield while NERICA-L-34 showed the lowest mean value. In conclusion, the SSR marker approach was able to detect differences that were significant enough to separate the six rice genotypes from one another. However, the similarities observed in some of their traits are an indication that the rice genotypes originated from a common ancestry. The results of the studies on the genetic diversity and the yield potentials of the six genotypes provide very useful information for yield improvement in future rice breeding programme in Africa.
