TITLE:
GENETIC DIVERSITY OF NIGERIAN ACCESSIONS OF SORGHUM (Sorghum bicolor L. Moench) BASED ON AGRONOMIC AND PHYTOCHEMICAL TRAITS
NAME: Dada Muftau I. [View Profile]
ADMISSION YEAR: 2014/2015
PG NUMBER: Pg13/0814
PROGRAMME: Crop Improvement and seed Enterprise Development
DEGREE AWARDED: M.AgSE
DATE OF DEFENCE: March, 2018
ABSTRACT
Interest in sorghum in Africa is increasing because of its use as a raw material for feed production and human consumption. However, high tannin content in the seeds poses huge challenges for sustainable use. The study therefore evaluated genetic diversity of sorghum and investigated the relationship between tannin and agro-morphological traits. Thirty-two landraces (NG/MR/12/11/124(10), NGB/SA/07/065, NG/AO/11/08/113, NGB 01900 and NGB 01896 among others) and seven improved Sorghum accessions (SAMSORG 43, SAMSORG 42, and SAMSORG 17 among others) were obtained from National Center for Genetic Resources and Biotechnology, Ibadan, Nigeria. The experiment was carried out during the late cropping season of 2015 at the Teaching and Research Farms of Federal University of Agriculture, Abeokuta, Ogun State, Nigeria on altitude 76 m above sea level, latitude 70 151 N and longitude 30 281 E. The experiment was laid out in a Randomized Complete Block Design in three replicates with a total of fifteen Sorghum plants maintained per plot. Data on thirteen agronomic traits (Grain yield/plant, Panicle/plant and 1000-grainweight among others) and tannin content of each accession were recorded on ten randomly selected plants and subjected to Analysis of Variance, mean values were separated using Duncan’s Multiple Range Test at p < 0.05 and broad-sense heritability was estimated from the variance components. Genotypic and phenotypic correlations among the agro-phyto-chemical traits were calculated. Principal Component and Cluster Analyses using Ward’s method were employed to study the variation pattern among the accessions. Result showed significant genotypic effect at both 1% and 5% probability levels for all investigated traits. High broad-sense heritability estimates of 99.8, 99.4, 74.2 and 71.5 were obtained for 1000-grain weight, tannin content, number of days to 50% tasseling and number of panicles per plant, respectively. Progress that could be expected from selecting the top 5% of the accessions for genetic advance ranged from 13.6% (for number of days to 50% tasseling) to 88.03% (for tannin content). Of the 14 principal components, only four had Eigen values greater than one and cumulatively explained approximately 78% of the total variation. Significant negative phenotypic and genotypic correlation were observed between grain yield per hectare and tannin content (r= -0.32**, r= -0.43**). Using Ward’s method, the dendrogram, produced five (I, II, III, IV, V) homogenous clusters. The three accessions found in cluster IV had higher 1000-grain weight (39.33 g) with lower tannin content (0.29 mg/g). Cluster V had 6 accessions with higher number of panicles per plant (4.33), grain yield per plant (341.61 g) and grain yield per hectare (22204.64 kg). The results indicated that sorghum is genetically diverse and there is possibility to exploit selection of relevant characters to increase the grain yield and reduce tannin content of sorghum. The study concluded that accessions: NG/MR/12/11/124(10), NGB/SA/07/065, SAMSORG 14, NG/AO/11/08/113, NGB 01900 and NGB 01896 were the highest grain yielders with moderate tannin content while NGB 01894, SAMSORG 43, SAMSORG 42 and SAMSORG 17 were accessions with low tannin content. Selection for seed yield improvement with low tannin content should therefore include an indirect selection for sorghum since they had significant role in improving the yield and low tannin content.