Molecular and Phylogenetic Diversity Studies of some Acha (Digitaria Spp.)Landraces of the Jos Plateau and its Environments

Abstract

The evaluation of the molecular and phylogenetic diversity ofAcha (Digitaria spp.) landraces of the Jos plateau and its environs, was carried out between 2012, 2013 and 2014.The phenotypic and genotypic characters of the different accessions showed that variability due to effect was more in genotype had more variability in genetic diversity for the morphological traits.Thirty accessions were collected from Tafawa Balewa Local Government Area(LGA) of Bauchi State; six LGAs of Plateau State and Jab LGA of Kaduna State and were screened during the cropping seasons of 2012, 2013and 2014 to evaluate their yield potentials and degree of relatedness. The randomized complete block design (RCBD) with three replications was employed for the field experiment. DNA extraction was carried out and Agarose Gel Electrophoresis was conducted on the restricted amplified DNA extracts using microsatellite primers developed for Digitaria exilis. The results showed that a high level of variability existed between the accessions with respect to plant height, stem girth, leaf length, leaf width, days to maturity and a 1000 seed weight. The principal component one (PC1) contributed 87.1, 78.3 and 91.5% in 2012, 2013 and 2014 respectively, of the total variation.Some of the accessionswhich were identified asDigitariaiburua, took the longest number of days to maturity and had the heaviest 1000 seed weight with an average of 0.72g. Those that were identified as Digitariaexilis, despite its early maturity date of an average of 132 days had an average 1000 seed weight of 0.62g. One of the accessions identified as D. barbinodis had the least number of days to maturity at 130 days and a mean 1000 seed weight of 0.51g. Correlation analyses revealed a highly significantand positive correlation between yield and the yield components.Dendrogramanalyses in all the years show that two distinct clusters separated the accessions into two morphotypes: Digitariaiburuagroup and D. exilis group.D. barbinodis, a different species was found to be highly related to the D. exilisgroup. The traits in the 2012 planting season were separated between the 96.79 to 93.59%, this was observed to be between the 100 and 94.62%, and the 99 and 96% for 2013 and 2014 cropping seasons respectively, indicating that there were no traits that were 100% similar. Selection for taller accessions, longer leaf length, wider stem girth and broader leaf width could to some extent, lead to higher yield in Acha production.RFLPs appear to suggest a clear separation of the 3 species (D. iburua, D. exilis and D. barbinodis) demonstrating the extent of their genetic differences at the molecular/DNA level.Evaluation of the phenotypic and genotypic characters for the different accessions in this study shows that the genotype had more variability in genetic diversity for plant height, leaf length, days to maturity and 1000 seed weight in the three year field trials.