PRELIMINARY MORPHOLOGICAL AND CYTOLOGICAL CHARACTERIZATION OF LONG SEASON SORGHUM (Sorghum bicolor) ACCESSIONS IN SOUTH WEST NIGERIA

Abstract

Sorghum [Sorghum bicolor (L) Moench] is grown in small proportion mainly for food and feed in south west Nigeria. Forty one sorghum accessions collected from three agro-ecological zones in Nigeria (Guinea, Sudan and Sahel savanna) were grown in south west Nigeria (Akure) and characterized using seventeen quantitative and qualitative traits. The objectives of the experiment were to identify the best promising accessions that can be used as parent in breeding long season sorghum and determine the extent of genetic variability and character association among the accessions. The experiment was laid in a Randomized Complete Block Design with two replicates and two ranges per plot. Two multivariate techniques [Principal Component Analysis (PCA) and Single Linkage Cluster Analysis (SLCA)] were used to analyse the magnitude and pattern of diversity among the accessions. Ten accessions were selected across the clusters from the SLCA for cytological studies. The morphological characterization result showed that the first four Principal components (PCs) from the PCA axis captured 99.01% of the total variance. The PCA showed that the flowering traits were the most variable. The accessions were grouped into six clusters based on their level of similarity by the SLCA. Accessions in Cluster VI with the highest mean cluster value for 9 out of the 11 traits analysed for can be selected as parents in breeding long season sorghum. Phenotypic coefficient of variation was higher than the genotypic coefficient of variation for all the characters studied. All the characters had high heritability except leaf width. There was a positive correlation between all the quantitative traits except brix content and leaf width. Significant genetic variation was observed among the forty-one sorghum accessions. The results obtained will help in breeding long season sorghum that are adaptable to the current soil and climate conditions in south west Nigeria.